Author name code: vince
ADS astronomy entries on 2022-09-14
author:"Vince, Istvan"
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Title: Spectroscopy of the massive interacting binary UU Cassiopeiae
Authors: Hadrava, P.; Cabezas, M.; Djurašević, G.; Garcés,
J.; Gorda, S. Y.; Jurkovic, M. I.; Korčáková, D.; Markov, H.;
Mennickent, R. E.; Petrović, J.; Vince, I.; Zharikov, S.
Bibcode: 2022A&A...663A...8H
Altcode: 2022arXiv220113275H
Context. The eclipsing close binary UU Cas is an interacting massive
double-periodic system with a gainer star partly hidden in an accretion
disk.
Aims: In order to study the physics of the accretion
process in greater detail, along with the structure and dynamics of
the circumstellar matter in the system, we supplement our previous
results obtained from photometry with an analysis of the spectra of
UU Cas.
Methods: We collected all available spectra used in
previous publications on UU Cas and we acquired new ones. The method
of disentangling was applied to this set of spectra spanning the
years 2008-2021. The orbital parameters were disentangled and a fit
of the separated component spectra by synthetic ones has been used to
determine the physical parameters of the component stars. We compared
the results to models of the evolution of interacting binaries.
Results: We found that in addition to the dominant role of the donor
star and a weak contribution of the gainer, the line profiles are
strongly influenced by the circumstellar matter. The absorption lines
reveal a presence of a disk wind emanating above the orbital plane. The
variability of Hα emission yields evidence of changes in the structure
of the circumstellar matter on a timescale of several orbital periods.
Title: Life, Educational and Scientific Activities of Professor
Mirjana Vukićević-Karabin (1933-2020)
Authors: Vince, I.; Atanacković, O.
Bibcode: 2020SerAJ.201...49V
Altcode:
We present a short biography and brief review of contributions of
professor Mirjana Vukićević-Karabin to the development of astrophysics
education at the University of Belgrade and to the research in physics
of the Earth ionosphere and the Sun. The bibliography of her papers is
given as well. We hope that the review of the two aspects of her work
will elucidate her important role in the development of astrophysics
in our country.
Title: New insights on the massive interacting binary UU Cassiopeiae
Authors: Mennickent, R. E.; Djurašević, G.; Vince, I.; Garcés, J.;
Hadrava, P.; Cabezas, M.; Petrović, J.; Jurkovic, M. I.; Korčáková,
D.; Markov, H.
Bibcode: 2020A&A...642A.211M
Altcode: 2020arXiv200901352M
We present the results of our study of the close binary UU
Cassiopeiae based on previously published multiwavelength photometric
and spectroscopic data. Based on eclipse timings from the last
117 years, we find an improved orbital period of Po =
8.d519296(8). In addition, we find a long cycle of
length T ∼ 270 d in the Ic-band data. There is no evidence
for orbital period change over the last century, suggesting that the
rate of mass loss from the system or mass exchange between the stars
is small. Sporadic and rapid brightness drops of up to ΔV = 0.3 mag
are detected throughout the orbital cycle, and infrared photometry
clearly suggests the presence of circumstellar matter. We model the
orbital light curve of 11 published datasets, fixing the mass ratio
and cooler star temperature from previous spectroscopic work: q = 0.52
and Tc = 22 700 K. We find a system seen at an angle of 74°
with a stellar separation of 52 R⊙, a temperature for the
hotter star of Th = 30 200 K and, for the hotter and cooler
stars, respectively, stellar masses of 17.4 and 9 M⊙,
radii of 7.0 and 16.9 R⊙, and surface gravities log g =
3.98 and 2.94. We find an accretion disk surrounding the more massive
star that has a radius of 21 R⊙ and a vertical thickness
at its outer edge of 6.5 R⊙; the disk nearly occults the
hotter star. Two active regions hotter than the surrounding disk are
found, one located roughly in the expected position where the stream
impacts the disk and the other on the opposite side of the disk. Changes
are observed in parameters of the disk and spots in different datasets.
Title: Illuminance and visibility at twilights
Authors: Vince, I.
Bibcode: 2018POBeo..98..225V
Altcode:
No abstract at ADS
Title: First spectra from the telescope Milankovic
Authors: Vince, O.; Jovanovic, M. D.; Vince, I.; Janjes, A.
Bibcode: 2018POBeo..98..341V
Altcode:
No abstract at ADS
Title: Aleksandar Kubičcela (1930-2017) - An Astrophysical Research
Pioneer at the Astronomical Observatory of Belgrade
Authors: Popović, L. Č.; Vince, I.
Bibcode: 2018SerAJ.196...29P
Altcode:
Here, we give a short biography and summary of scientific contributions
of Aleksandar Kubičela, a doyen of astronomy in Serbia, and an
astrophysical research pioneer at the Astronomical Observatory of
Belgrade. Additionally, we evoke some of our memories concerning
scientific collaboration with Aleksandar Kubičcela.
Title: Variation of the Mn I 539.4 nm line with the solar cycle
Authors: Danilovic, S.; Solanki, S. K.; Livingston, W.; Krivova, N.;
Vince, I.
Bibcode: 2016A&A...587A..33D
Altcode: 2015arXiv151101286D
Context. As a part of the long-term program at Kitt Peak National
Observatory (KPNO), the Mn I 539.4 nm line has been observed for
nearly three solar cycles using the McMath telescope and the 13.5 m
spectrograph in double-pass mode. These full-disk spectrophotometric
observations revealed an unusually strong change of this line's
parameters over the solar cycle.
Aims: Optical pumping by the Mg
II k line was originally proposed to explain these variations. More
recent studies have proposed that this is not required and that
the magnetic variability (I.e., the changes in solar atmospheric
structure due to faculae) might explain these changes. Magnetic
variability is also the mechanism that drives the changes in total
solar irradiance variations (TSI). With this work we investigate this
proposition quantitatively by using the same model that was earlier
successfully employed to reconstruct the irradiance.
Methods:
We reconstructed the changes in the line parameters using the model
SATIRE-S, which takes only variations of the daily surface distribution
of the magnetic field into account. We applied exactly the same model
atmospheres and value of the free parameter as were used in previous
solar irradiance reconstructions to now model the variation in the Mn
I 539.4 nm line profile and in neighboring Fe I lines. We compared
the results of the theoretical model with KPNO observations.
Results: The changes in the Mn I 539.4 nm line and a neighbouring Fe
I 539.52 nm line over approximately three solar cycles are reproduced
well by the model without additionally tweaking the model parameters,
if changes made to the instrument setup are taken into account. The
model slightly overestimates the change for the strong Fe I 539.32 nm
line.
Conclusions: Our result confirms that optical pumping
of the Mn II 539.4 nm line by Mg II k is not the main cause of its
solar cycle change. It also provides independent confirmation of solar
irradiance models which are based on the assumption that irradiance
variations are caused by the evolution of the solar surface magnetic
flux. The result obtained here also supports the spectral irradiance
variations computed by these models.
Title: An Echelle Spectrograph for the Milankovic Telescope
Authors: Vince, I.; Skuljan, J.
Bibcode: 2013POBeo..92...41V
Altcode:
In this paper we report some general outlines on a construction of a
high resolution échelle spectrograph, which we propose to build for
our future 1.5-m class Milanković Telescope (MILanković Échelle
Spectrograph - MILES). MILES would be a mechanically stabilised
and temperature controlled high-resolution (R∼50000) fibre-fed
spectrograph for visible and near infrared wavelength region of
electromagnetic radiation. Here, a white-pupil optical design of the
spectrograph is described and the main optical and mechanical elements
are discussed. The set of these elements includes: an optical fibre
for a link between the telescope and the spectrograph entrance slit, an
échelle grating, the collimator and camera optics, the cross-disperser
prisms, a CCD detector and an optical table. Since we plan to build
MILES from commercially available elements, it has been possible to
estimate its price, which amounts to about 550 kEU.
Title: Modeling of Interacting Binary Systems
Authors: Latkovic, O.; Djurasevic, G.; Vince, I.; Cseki, A.
Bibcode: 2013POBeo..92..129O
Altcode:
We present a summary of recent results and publications of the
binary star research group within the project Stellar Physics at the
Astronomical Observatory of Belgrade. Our study is mainly focused on
close, interacting binary stars in various stages of mass transfer, from
systems in deep overcontact configurations, to systems with accretion
disks. The primary method of our research is modeling of interesting
systems based on photometric and spectroscopic observations. Typically,
this results in determination of physical parameters of the components
and new insights on the nature of the complex interactions between
them. The binary system model that we use for this purpose is currently
being upgraded in order to accommodate high-precision satellite
observations of planetary transits and stellar pulsations.
Title: A study of the interacting binary system V455 Cygni
Authors: Djurašević, G.; Vince, I.; Antokhin, I. I.; Shatsky, N. I.;
Cséki, A.; Zakirov, M.; Eshankulova, M.
Bibcode: 2012MNRAS.420.3081D
Altcode:
We present a detailed study of the active eclipsing binary V455 Cygni
(V455 Cyg), based on spectroscopic and photometric data from the 1.25-m
and 0.6-m telescopes at the Crimean SAI Observatory and the 0.6-m
telescope at the Maidanak Observatory, collected in the period from
2000 to 2010. Spectroscopic evidence and the shape of the light
curves suggest the existence of a geometrically and optically thick
accretion disc around the more massive and hotter gainer. We used a
model of the binary system based on the Roche geometry and including
the accretion disc with active regions to estimate the orbital and
physical parameters of the components of V455 Cyg. Our model fits the
observations very well for all individual passband light curves. The evident seasonal changes in the shape of the light curves,
including prominent variations in the depth of the eclipses, can be
explained by the changes in the parameters of the accretion disc and
the active regions of the disc, arising in turn from a variable rate
of mass transfer.
Title: Measurements and Modeling of (0,0) and (1,0) Bands of the o2
Atmospheric System
Authors: Guineva, V.; Werner, R.; Vince, I.; Kirilov, A.
Bibcode: 2011simi.confQ..26G
Altcode:
Ground based spectroscopic observations have been used for the effective
temperature evaluation. Measurements of rotational absorption lines
from the P branches of the (0,0) and (1,0) bands of the molecular
oxygen atmospheric system have been performed by the solar telescope of
Belgrade Astronomical Observatory and by the spectroscopic system in
Stara Zagora. Synthetic spectra of the above bands have been created
based on line-by-line calculations. The theoretical equivalent widths
have been computed. The theoretical and measured line profiles and
their equivalent widths have been compared. The dependence of the
equivalent widths on the rotational quantum number has been worked out
assuming strong absorption. It allows the evaluation of the effective
atmosphere temperature. The possible contaminations as water vapour
lines in some cases are discussed. The theoretical estimates and the
measurement results have been examined.
Title: New spectral observations of the EBS star UU Cas
Authors: Markov, H.; Markova, N.; Vince, I.; Jurasevich, G.
Bibcode: 2011BlgAJ..15...87M
Altcode:
High-resolution (R = 30,000) spectroscopy of the Eclipsing Binary System
UU Cas obtained with the Coude spectrograph of the 2m telescope of
the Bulgarian NAO is presented. The observations cover three spectral
regions: the one centred on λ=4520 Å, the other one centred on
λ=4720 Å, and the region around Hβ. In each region detailed line
identification and radial velocity measurements were performed. The
new data together with those published by Markov et al. te{Markov}
are used to obtain a better solution of the RV curve and to get some
insight into the nature of the system.
Title: Accretion Disks in Massive Binary Systems
Authors: Djurašević, G. R.; Vince, I.; Atanacković, O.
Bibcode: 2010ASPC..435..301D
Altcode:
The results of our investigations of some massive close binaries (CB)
(RY Sct, V448 Cyg, UU Cas and V455 Cyg), based on the photometric and
spectroscopic observations indicate the existance of the accretion
disk around the more massive component, located deep inside the Roche
lobe. The light curve shapes of some of this systems are similar to
the ones of the overcontact systems like W UMa, but the nature of
these massive CBs is completely different. Here we present the models
of these systems and their basic elements.
Title: Accretion disc in the eclipsing binary AU Mon
Authors: Djurašević, G.; Latković, O.; Vince, I.; Cséki, A.
Bibcode: 2010MNRAS.409..329D
Altcode: 2010MNRAS.tmp.1202D; 2010arXiv1007.3872D
We analyse the CoRoT and V-passband ground-based light curves of the
interacting close binary AU Mon, assuming that there is a geometrically
and optically thick accretion disc around the hotter and more massive
star, as inferred from the photometric and spectroscopic characteristics
of the binary. Our model fits the observations very well and provides
estimates for the orbital elements and physical parameters of the
components and of the accretion disc. Based on photometry collected
by the CoRoT space mission. The CoRoT space mission was developed and
is operated by the French space agency CNES, with participation of
ESA's RSSD and Science Programmes, Austria, Belgium, Brazil, Germany,
and Spain. E-mail: gdjurasevic@aob.rs
Title: Contamination of the 5394 Å spectral region by telluric lines
Authors: Vince, I.; Vince, O.
Bibcode: 2010NewA...15..669V
Altcode:
The spectral region in the vicinity of 5394 Å contains three
prominent photospheric spectral lines, which can be used as a
solar plasma diagnostic tool. The occurrence of telluric lines in
this region is a potential source of systematic and random errors
in these solar spectral lines. The goal of our investigation was
to determine the telluric line contamination of this interesting
spectral region. Several series of high-resolution solar spectra
within an interval of about 4 Å around the 5394 Å wavelength were
observed at different zenith distances of the Sun. Comparison of these
spectra has permitted identification of telluric lines in this spectral
interval. The observations were carried out with the horizontal solar
spectrograph of the Heliophysical Observatory in Debrecen. Telluric
feature blending was identified in the blue and red wings of the Fe
I 5393.2 Å line, and in the local continuum of the Mn I 5394.7 Å
line. The blue wing of the Fe I 5395.2 Å line is contaminated by a
weak telluric feature too. The red continuum of this line has a more
prominent telluric contamination. A dozen of water vapor telluric lines
that determined the observed telluric features were identified in this
spectral interval. The profiles of three telluric lines that have a
significant influence on both the profiles of solar spectral lines
and the level of local continuum were derived, and the variation of
their parameters (equivalent width and central depth) with air mass
were analyzed.
Title: Binary 15 Monocerotis and Star Cluster NGC 2264
Authors: Cvetkovic, Z.; Ninkovic, S.; Vince, I.
Bibcode: 2010POBeo..90...25C
Altcode:
The orbit of 15 Mon (close pair CHR 168 Aa-Ab) was recently calculated
on the basis of speckle measurements only. Four new measurements,
performed after the orbit calculation, satisfy this orbit very well. The
orbital elements and the mass values expected for the components,
as well as their distance moduli, result in a distance of 15 Mon in a
very good agreement with the distance to NGC 2264, but disagrees with
the trigonometric distance of the binary. On the basis of the orbital
elements and mass ratio the line-of-sight velocity of the binary mass
centre is determined. It is found that the value of this velocity
is within the limits expected for stars belonging to NGC 2264. Its
difference from the expected mean in the field of NGC 2264 agrees well
with the value mentioned in the literature.
Title: Spectroscopic Observations of UU Cas
Authors: Markov, H.; Vince, I.; Markova, N.; Djurasevic, G.
Bibcode: 2010POBeo..90..159M
Altcode:
High dispersion (R = 30000) spectra of the eclipsing binary system UU
Cas are presented for the first time. Spectra covering 15 different
phases were taken in two spectral regions - the vicinity of H_α and
another centered on 5800Å. Seven spectral lines were identified in
common. Four of them belonging to the brighter component were used
to construct radial velocity curve. Some constrains on the spectral
classification of the components are presented.
Title: Proceedings of the 6th SREAC Meeting - "Astrophysics and
Astrodynamics in Balkan Countries in the International Year of
Astronomy"
Authors: Vince, I.; Bonev, T.
Bibcode: 2010POBeo..90.....V
Altcode:
No abstract at ADS
Title: A Method for Determination of Water Vapor Content from Solar
Spectrum: Preliminary Results
Authors: Jovanovic, M.; Vince, I.
Bibcode: 2010POBeo..90..141J
Altcode:
For precise spectrophotometric observations of solar spectral lines,
it is necessary to remove the systematical errors caused by telluric
line blending. Calibration methods are usually applied for removing
these errors. Calibration in the case of telluric lines that originate
from water vapor is more complicated than in the case of molecular
oxygen lines, since the amount of water vapor in Earth atmosphere is
unpredictable. We present here a method for determination of water
vapor amount in atmosphere, based on the measured ratio of water vapor
and molecular oxygen spectral line parameters.
Title: A new orbit of binary 15 Monocerotis
Authors: Cvetković, Z.; Vince, I.; Ninković, S.
Bibcode: 2010NewA...15..302C
Altcode:
In the paper new orbital elements for 15 Mon obtained from speckle
interferometric measurements only are reported. The first speckle
measurement originates from 1988 and up to now seven more speckle
measurements have been made. For this binary orbits were determined
earlier by combining spectroscopic and speckle measurements and
spectroscopic and astrometric measurements. New speckle measurements
dating after the periastron passage have a significant discrepancy
from the ephemeridal values. Our orbit has a period significantly
longer than the earlier ones. In the case of the earlier orbits the
period was determined from radial velocity data. The existing data
of such kind for this binary are reanalyzed here and combined with
our orbital elements. Binary 15 Mon is a member of open cluster NGC
2264. The distance to this cluster has been determined many times and
different values have been reported. By analyzing the available data
we find that the distance to 15 Mon is most likely about 720 pc. Our
new orbital elements combined with this distance yield a total mass of
59.1M⊙. This is in a good agreement with values expected
according to the spectral types of the components (primary O7V,
secondary O9.5Vn).
Title: Orbit of Binary 15 Monocerotis
Authors: Cvetkovic, Z.; Vince, I.; Ninkovic, S.
Bibcode: 2009POBeo..86..331C
Altcode:
In the paper new orbital elements obtained from speckle interferometric
measurements only for 15 Mon are reported. For this binary they
were determined earlier by combining spectroscopic and speckle
measurements and spectroscopic and astrometric measurements. A new
speckle measurement dating after the periastron passage of the secondary
has a significant discrepancy from the ephemeridal value. Our revised
orbit has a period significantly longer than the earlier ones. This
pair is bright (apparent magnitude of primary 4.66, i.e. 5.9 of
secondary), of an early spectral type (primary O7V, secondary O9.5Vn)
and is a member of open cluster NGC 2264. By analyzing the available
data we find that the distance to 15 Mon is most likely about 750 pc,
i.e. the total mass most likely about 53.4 M_{⊙}. The new orbital
elements combined with this distance yield a total mass expected for
the spectral types of the components.
Title: Accretion disc in the massive V448 Cygni system
Authors: Djurašević, G.; Vince, I.; Khruzina, T. S.;
Rovithis-Livaniou, E.
Bibcode: 2009MNRAS.396.1553D
Altcode: 2009MNRAS.tmp..680D
The UBV light curves of the early-type eclipsing binary V448 Cygni,
obtained at the Abastumani Astrophysical Observatory from 1964 to 1967,
are re-analysed here. The analysis was made assuming the presence
of an accretion disc in the system, as inferred from the light-curve
shape and spectroscopic characteristics of the system. The Roche model
of a binary was used, containing a geometrically and optically thick
accretion disc around the hotter and more massive star. By solving the
inverse problem, the orbital elements and the physical parameters of
the system components and of the accretion disc were estimated. This
result is important for understanding the star formation and evolution
processes in the systems with massive components.
Title: Accretion Disk in the Massive Binary RY Scuti
Authors: Djurašević, G.; Vince, I.; Atanacković, O.
Bibcode: 2008AJ....136..767D
Altcode:
The UBVR light curves of the massive eclipsing binary RY Sct, obtained
at the Maidanak Observatory from 1979 to 1992, have been re-analyzed in
order to prove the hypothesis of the presence of an accretion disk in
the system. This hypothesis is supported by a new spectroscopic study
of Grundstrom et al., and by a specific light-curve shape exhibiting
a slight asymmetry around the secondary minima and a small difference
in the height of the successive maxima. The light-curve analysis was
performed using a Roche model of a binary containing a geometrically
and optically thick accretion disk around the more massive primary
star. By solving the inverse problem, the orbital elements and the
physical parameters of the system components and of the accretion disk
were estimated for all the individual UBVR light curves. The model
gives a consistent solution for the RY Sct binary system and supports
the hypothesis of the existence of an optically thick disk around the
massive component. Our results suggest a mass exchange between the
components and a mass loss from the system. This could be considered
as a possible mechanism of the formation of the accretion disk around
the more massive component and of the circumbinary envelope of toroidal
form in the orbital plane of the system.
Title: Orbit of Binary 15 Monocerotis
Authors: Cvetkovc, Zorica; Vince, Istvan; Ninkovic, Slobodan
Bibcode: 2008arXiv0804.0698C
Altcode:
In the paper new orbital elements obtained from speckle interferometric
measurements only for 15 Mon are reported. For this binary they were
determined earlier by combining spectroscopic and speckle measurements
and spectroscopic and astrometric measurements. A new speckle
measurement dating after the periastron passage of the secondary has a
significant discrepancy from the ephemeridal value. Our revised orbit
has a period significantly longer than the earlier ones. With regard
that in the case of the earlier orbits the period was determined from
spectroscopic measurements, i.e. from radial velocity data, the existing
data of such kind for this binary are analyzed here and combined with
our orbital elements. The first speckle measurement originates from 1988
and up to now three more speckle measurements have been made. This pair
is bright (apparent magnitude of primary 4.66, i.e. 5.9 of secondary),
of an early spectral type (primary O7V, secondary O9.5Vn) and is
a member of open cluster NGC 2264. The distance to this cluster has
been determined many times and different values have been reported. By
analyzing the available data we find that the distance to 15 Mon is most
likely about 750 pc, i.e. the total mass most likely about 53.4${\cal
M}_{\odot}$. The new orbital elements combined with this distance
yield a total mass expected for the spectral types of the components.
Title: On the solar abundance of indium
Authors: Vitas, N.; Vince, I.; Lugaro, M.; Andriyenko, O.; Gošić,
M.; Rutten, R. J.
Bibcode: 2008MNRAS.384..370V
Altcode: 2008MNRAS.tmp...25V; 2007arXiv0711.2166V
The generally adopted value for the solar abundance of indium is over
six times higher than the meteoritic value. We address this discrepancy
through numerical synthesis of the 451.13-nm line on which all indium
abundance studies are based, both for the quiet Sun and the sunspot
umbra spectrum, employing standard atmosphere models and accounting
for hyperfine structure and Zeeman splitting in detail. The results,
as well as a re-appraisal of indium nucleosynthesis, suggest that
the solar indium abundance is close to the meteoritic value, and
that some unidentified ion line causes the 451.13-nm feature in the
quiet-Sun spectrum.
Title: New Spectroscopic Results for the Eclipsing Binary HS Her
Authors: Latković, O.; Markov, H.; Vince, I.
Bibcode: 2008RoAJ...18Q.125L
Altcode:
No abstract at ADS
Title: Possible Accretion Disk in the Active Binary System V455 Cygni
Authors: Djurašević, G.; Vince, I.; Antokhin, I.; Zakirov, M.;
Eshankulova, M.
Bibcode: 2008RoAJ...18S.126D
Altcode:
No abstract at ADS
Title: Identification of Phase-Independent Spectral Lines in Close
Binary V455 Cyg: I. Telluric Lines
Authors: Cseki, A.; Vince, I.; Latkovic, O.; Antokhin, I. I.
Bibcode: 2007SerAJ.174...77C
Altcode:
Spectroscopic observations of close binary star V455 Cygni reveal
many lines that originate in interstellar and circumstellar medium and
the atmosphere of the Earth; we found over two hundred such spectral
features, and in this paper we present the list of telluric lines
we identified through comparison with HITRAN database of molecular
lines. The lines that remain unidentified or show peculiar behavior
will be discussed in the second part of the paper.
Title: Is the Mn I 539.4 nm Variation with Activity Explained?
Authors: Vitas, N.; Vince, I.
Bibcode: 2007ASPC..368..543V
Altcode:
The photospheric Mn I 539.4 nm line in the solar spectrum shows unusual
variability with the solar cycle in that its depth decreases with
increasing activity. \citet{nv-2001A&A...369L..13D} claimed that
this phenomenon is due to interlocking between the chromospheric Mg II
h & k lines and an overlapping Mn I multiplet. In this contribution
we test this hypothesis by synthesizing Mn I 539.4 nm line including
these interlocking lines for a range of standard solar models and
then combining resulting profiles without and with interlocking to
emulate the full-disk profile variation. We find that the interlocking
gives only a minor contribution; the largest one comes from different
temperature stratifications in the photospheric layers of the various
models.
Title: Magnetic source of the solar cycle variation of the Mn I
539.4 nm line
Authors: Danilović, S.; Solanki, S. K.; Livingston, W.; Krivova,
N.; Vince, I.
Bibcode: 2007msfa.conf..189D
Altcode:
As a part of the long term program at KPNO, the Mn I 539.4 nm line has
been observed for nearly three solar cycles using the McMath telescope
and the 13.5 m spectrograph in double pass mode. These full-disk
spectrophotometric observations revealed an unusually large amplitude
change of its parameters over the solar cycle and its correlation with
Ca II K intensity. One of the proposed explanations for this phenomenon
is the optical pumping by the Mg II k line. With this work we would like
to show that this may not be the main mechanism behind the change. We
reconstructed the changes of the line parameters using a model that
takes into account only changes of the daily surface distributions of
magnetic field. This model has already been used to successfully model
total solar irradiance. We now apply it for modelling the Mn I line,
as well as its neighboring Fe I line using exactly the same value
of the free parameter as used for the reconstruction of total solar
irradiance. We reproduce well the Mn I and Fe I line changes over the
cycle purely with LTE modelling. This indicates that optical pumping
of the Mn I line by Mg II k is not the main cause of its solar cycle
change and sets an independent constraint on solar irradiance models.
Title: Astrometric Solar Observations from Belgrade Observatory
Authors: Jakić, Tatjana; Dačić, Miodrag; Vince, Istvan
Bibcode: 2007RoAJ...17S.103J
Altcode:
No abstract at ADS
Title: Ceseb: a Report on Latest Results
Authors: Hegedus, T.; Latkovic, O.; Markov, H.; Vince, I.; Cseki,
A.; Nuspl, J.; Markova, N.; Rovithis-Livaniou, E.; Vinko, J.
Bibcode: 2007OAP....20...76H
Altcode:
Central-East-South European Binary star study group - CESEB - is an
international research team focused on the study of binary stars through
combined spectral and photometric observations that can be made using
the Bulgarian NAO 2m telescope and several smaller telescopes located
at various places in the Central East South European region. This
paper is a report on our activities and results.
Title: Program of Telluric Lines Monitoring
Authors: Vince, I.; Kos, P.; Latkovic, O.; Martinovic, N.; Gosic,
M.; Stojadinovic, J.
Bibcode: 2006SerAJ.173..101V
Altcode:
A new observational program of telluric lines monitoring was introduced
at Belgrade Astronomical Observatory. The ultimate goal of this program
is to investigate the properties of Earth's atmosphere through modeling
the observed profiles of telluric lines. The program is intend to
observe infrared molecular oxygen lines that were selected according to
spectral sensitivity of the available CCD camera. In this paper we give
the initial and the final selection criteria for spectral lines included
in the program, the description of equipment and procedures used for
observations and reduction, a review of preliminary observational
results with the estimated precision, and a short discussion on the
comparison of the theoretical predictions and the measurements.
Title: First results of the Central-East-South European Binary Star
Study Group (CESEB)
Authors: Hegedüs, T.; Nuspl, J.; Markova, N.; Markov, H.;
Rovithis-Livaniou, H.; Vince, I.; Vinkó, J.
Bibcode: 2006Ap&SS.304...51H
Altcode: 2006Ap&SS.tmp....3H
Several eclipsing binary systems have been selected for combined
spectral and photometric observations using the Bulgarian NAO 2 m
telescope and several smaller telescopes located at various places in
the CESE region. Preliminary results, based on a pilot study started
in 2001, about radial velocity and light curve variations of the active
W UMa system LS Del are presented here.
Title: Sunspots motions in the 22^nd cycle of activity
Authors: Tomic, A. S.; Vince, I.
Bibcode: 2006IAUJD...8E...8T
Altcode:
We handled approximately 30 000 rows with data for 5744 sunspots,
obtained on Debrecen Heliophysical Observatory, for years 1986-1989 and
1993-1995. By method of last squares we solved for each spot inverse
relations between time of observation, angular distance from central
meridian and latitude. On this way were obtained mean equatorial and
mean meridional motion, giving parameters of rotation for 90 latitude
zones width of one degree. The averaged sideral equatorial angular
speed of rotation: omega = 2.91+/-0.01[micro rad/ day], and: A =
-0.65+/-0/01 [micro rad/day] were obtained. Solving second inverse
problem - Busso's equation, were derived characteristic equatorial
periods for different latitudes, from sunspots meridional motion. We
obtained values between 32 day on the pole, and 400 years for latitude
2.5 degree. Also, covariance of spot motions along equator and meridian
is calculated for all 5744 spots in 90 degree of latitude, which fully
confirmed Ward's model of angular moment transport.
Title: Stellar spectrograph of the Belgrade Astronomical Observatory
Authors: Lalovic, A.; Vince, I.
Bibcode: 2006POBeo..80..293L
Altcode:
The main features of the new SectraPro-750 spectrograph of Belgrade
Astronomical Observatory are given in this paper. The instrumental
profile of the spectrograph for the 1200 l/mm grating is determined
using a fiber optic bundle with fibers arranged in a pseudo-slit
pattern. This instrumental profile is compared to the instrumental
profiles obtained when the same fiber optic bundle illuminates
the entrance slit at different widths from appropriate instrumental
profiles. The practical spectral purities and the spectral resolutions
for different entrance slit widths are obtained. The variation of the
reciprocal linear dispersion with wavelength in the spectral range 350 -
600 nm is presented.
Title: Line identification in some Algol-type stars
Authors: Lalovic, A.; Latkovic, O.; Cséki, A.; Vince, I.
Bibcode: 2006POBeo..80..299L
Altcode:
Several binary stars of Algol type were observed at National
Astronomical Observatory--Rozhen with 2m telescope using Coude
spectrograph. Observations were made from 2002 to 2004. We present the
preliminary results of reduction of these spectra and identification
of some spectral lines.
Title: The Central-East-South-European Binary Star Group. Some First
Results .
Authors: Hegedüs, Tibor; Nuspl, János; Markova, Nevyana; Markov,
Haralambi; Rovithis-Livaniou, Helen; Vince, Istvan; Vinkó, Jozséf
Bibcode: 2006RoAJ...16S.159H
Altcode: 2006RoAJS..16..159H
No abstract at ADS
Title: Formation of Neutral Manganese Lines Potentially Suitable
for Plasma Diagnostics
Authors: Vitas, N.; Danilović, S.; Atanacković-Vukmanović, O.;
Vince, Ištvan
Bibcode: 2005ESASP.600E..73V
Altcode: 2005dysu.confE..73V; 2005ESPM...11...73V
No abstract at ADS
Title: Characteristics of the Belgrade Astronomical Observatory's
Stellar Spectrograph
Authors: Vince, I.; Lalovic, A.
Bibcode: 2005SerAJ.171...55V
Altcode:
In this paper the main features of the new SpectraPro-750 spectrograph
of Belgrade Astronomical Observatory are described. The instrumental
profile of the spectrograph for the 1200 l/mm grating is determined
using a fiber optic bundle with fibers arranged in a pseudo-slit
pattern. This instrumental profile is compared to the instrumental
profiles obtained when the same fiber optic bundle illuminates the
entrance slit with different widths. From appropriate instrumental
profiles the practical spectral purities and the spectral resolutions
for different entrance slit widths are obtained. The variation of the
reciprocal linear dispersion with wavelength in the spectral range
350 - 600 nm is determined. A proposal for a link between telescope
and the spectrograph is given.
Title: The Observed MnI 539.47 nm Spectral Line in Three Sunspots
of the NOAA 0431 Complex Active Region
Authors: Vince, O.; Vince, I.
Bibcode: 2005ASPC..346..423V
Altcode:
The spectra of the MnI 539.47 nm spectral line was observed in three
sunspots of the NOAA 0431 active region on a three successive days. The
observation was made with the horizontal solar spectrograph at the
Heliophysical Observatory of Debrecen, Hungary. The spectra of each
sunspot were cropped into several boxes perpendicular to the dispersion
axis in such a way to cover their umbra, penumbra and surroundings. The
cropped spectra were thereafter reduced and the manganese spectral line
parameters (equivalent width, central depth and full width at half of
the maximum intensity) were measured. Finally, the variation of the
spectral line parameters along the spectrograph slit were determined
and analyzed.
Title: The Mn I 539.47 nm Line Variation in Solar Active Regions
Authors: Vince, I.; Vince, O.; LudmÁNy, A.; Andriyenko, O.
Bibcode: 2005SoPh..229..273V
Altcode:
It is a well-established fact that the Mn I 539.47 nm line
exhibits significant cycle dependence similar to lines arising in
the chromosphere which are affected by non-thermal heating in the
chromospheric plages. Among these lines the case of the Mn I 539.47
nm line seems unique. It is of photospheric origin on the basis
of theoretical calculations but its cyclic dependence hints at a
chromospheric nature. The present work provides further evidence to both
connections. The line exhibits asymmetry features and a center-to-limb
variation as though influenced by the photospheric granulation. On the
other hand an enhancement of the central intensity has been detected
in a well identifiable Ca plage area. The line seems to be a promising
candidate as an irradiance variation indicator.
Title: Investigations of the MnI 539.47 nm and MnI 542.04 nm Lines
in Solar Plages
Authors: Vince, I.; Gopasyuk, O.; Gopasyuk, S.; Vince, O.
Bibcode: 2005SerAJ.170..115V
Altcode:
We observed the MnI 539.47 nm and 542.04-nm line profiles in the
quiet photosphere and plage regions in 1998 and 2001, and measured
the full widths at half maximum, equivalent widths and depths of these
profiles. The relative changes of the MnI 539.47 nm line parameters,
normalized to the values obtained for quiet photosphere, as a
function of magnetic field strength in plages is analyzed. We found,
for plage region observed in 1998, that both the equivalent width
and the depth of the line profile decrease with increasing strength
of magnetic filed in plage at a rate of 9x10-4/Gauss, but
the full width at half maximum does not show any significant regular
changes. Based on these results, the variations of the MnI 539.47 nm
spectral line in solar flux with activity cycle could be explained by
the variation of solar surface coverage with plages. For observations
in 2001, the equivalent width and the depth of this line profile also
decrease with increasing strength of magnetic filed in plage, but
there are significant differences in the behavior of line parameters
in comparison with the 1998 values. Comparison of changes of the
MnI 539.47 nm line parameters with the parameters of the MnI 542.04 nm
line in 1998 shows a clear discrepancy between them. On the contrary,
in 2001 the full widths at half maximum and the equivalent widths of
these two lines behaved in a similar fashion.
Title: Time Series Analysis of Long Term Full Disk Observations Of
The Mn I 539.4 nm Solar Line
Authors: Danilovic, S.; Vince, I.; Vitas, N.; Jovanovic, P.
Bibcode: 2005SerAJ.170...79D
Altcode:
The equivalent width and central depth data of Mn 539.4 nm solar
spectral line, observed in the period from 1979 to 1992 at Kitt
Peak Observatory, was analyzed in pursuit for periodic changes. As
the observations are highly unevenly sampled, test if the periods
really exist in the observed data was needed. Two different methods
for spectral analysis were applied to synthesized data sampled in the
same way as observations. Comparation of these results with results
obtained from the observed data showed that the parameters display
at least three periodic changes with the periods of: 11-years,
quasi-biannual and 27-days.
Title: The reduction of eclipsing binary stars spectra observed at
Rozhen Observatory
Authors: Lalović, A.; Vince, I.
Bibcode: 2005MSAIS...7..170L
Altcode:
Several binary stars of Algol type were observed at Rozhen Observatory
with 2m telescope using Coude spectrograph. Observations were made
from 2001 to 2004. We present the preliminary results of reduction of
these spectra.
Title: NLTE Effects in formation of variable Mn I 539.4 nm line in
solar spectrum
Authors: Vitas, N.; Vince, I.
Bibcode: 2005MmSAI..76.1064V
Altcode:
On the basis of NLTE profile calculations obtained by employing the
radiative transfer code MULTI, the influence of the uncertainties
of various parameters important in the formation of the photospheric
Mn I 539.4 nm spectral line are discussed. Two cases are separately
considered: with and without energy transfer between Mg II and Mn
I. All calculations are performed with model atmospheres of Fontenla
et al. (1999).
Title: Variability of the Mn I 539.4 nm solar spectral line parameters
with solar activity.
Authors: Danilovic, S.; Vince, I.
Bibcode: 2005MmSAI..76..949D
Altcode:
The time analysis of Mn I 539.4 nm parameters, observed in solar
flux spectrum, shows high degree of correlation with sunspot area
and Mg II c/w index time spectra. The more pronounced correlation
between equivalent width of this line with Mg II index implies that
bright magnetic elements are important source of the line parameters
variation. We synthesized line profiles, taking into account the
coverage of solar surface with different features, at various solar
activity levels and compared them with observations. The result shows
very good correspondence between modelled and observed change.
Title: The Mn I 539.47 nm Spectral Line Parameters in Function of
the UV Flux Estimation
Authors: Vince, O.; Vince, I.
Bibcode: 2005HvaOB..29..271V
Altcode:
Since the UV solar irradiance variation is the main cause of the
ozone layer corpulence modification, which on the other side might
influence the climate and life on the Earth, its investigation is of
great importance. As a proxy for the UV solar irradiance estimation,
the Mg II index has been introduced. It is derived from the Mg II
doublet centred at the 279.9 nm. It has been shown that there is a
connection between the Mg II k 279.55 nm chromospheric and Mn I 539.47
nm photospheric spectral lines through optical pumping effect. This
might be a reason for correlation between Mg II index and Mn I line
parameters. In this paper, the Mn I 539.47 nm spectral line, as a
possible proxy for the UV flux estimation, is presented.
Title: Sensitivity of the MnI 539.47 nm Spectral Line to Solar
Activity
Authors: Danilovic, S.; Vince, I.
Bibcode: 2004SerAJ.169...47D
Altcode: 2005SerAJ.169...47D
CCD observations of the MnI 539.47 nm spectral line in the solar flux
made at the Astronomical Observatory in Belgrade between 1994 and 2003
have been reduced and certain line parameters -the equivalent width,
full width at half maximum and central depth have been derived. The
variation of these parameters with the solar activity has been
evaluated. The relative variation of the equivalent width from minimum
to maximum of solar activity was found to be 1.4%, while the variation
of the central depth is 2.3%. The full width at half maximum remains
practically constant.
Title: Iron Abundance Determination for the Solar-Like Stars HR4345
and HR6573
Authors: Vince, O.; Vince, I.
Bibcode: 2004SerAJ.169...41V
Altcode: 2005SerAJ.169...41V
Using the BLACKWELL software package written by R.O. Gray, the iron
abundance of the solar-like stars HR 4345 and HR 6573 has been
determined. The method is based on determination of the minimum
dispersion (or the region of least confusion) of the iron abundance
versus microturbulent velocity functions for some selected spectral
lines of neutral iron. The input data used by BLACKWELL are the observed
equivalent widths of several spectral lines of neutral iron. They are
obtained from spectra observed at the Observatoire de Haute-Provence,
France, with the 1.52-m telescope and Aurelie spectrograph. Reduction
of the raw spectra and the measurement of the equivalent widths of
spectral lines are carried out using IRAF and SPE software packages. The
measured values of iron abundances of HR 4345 and HR 6573 are 7.72 +-
0.03 and 7.63 +- 0.05 respectively.
Title: On the Modifications of Oscillator Strengths and Damping
Constants of Fe I Spectral Lines from 500 nm to 510 nm
Authors: Cséki, A.; Latković, O.; Vince, I.
Bibcode: 2004SerAJ.168...37C
Altcode:
We modified oscillator strengths and enhancement factors of van der
Waals damping constants for 84 moderately strong and weak neutral
iron spectral lines between 500 nm and 510 nm, by fitting the solar
synthetic spectrum to the observed one. We have found significant
difference between the oscillator strengths and damping constants
taken from an extensive spectral line list, frequently used for
spectral synthesis, and their modified values. Our findings include:
(1) the mean value of the distribution of the difference between our
and listed oscillator strengths is -0.31dex and its width is 0.42
dex, (2) a decrease of this difference with increasing equivalent
width of spectral lines, (3) unusually high values of the obtained
enhancement factors in comparison with the results of other authors, (4)
a decrease of enhancement factor with increasing excitation potential
for lines with equivalent width greater than 7.5 pm, (5) a decrease of
enhancement factors with increasing equivalent width and (6) a decrease
of enhancement factors with increasing oscillator strengths.
Title: The observed MnI 539.47 nm spectral line profile in the
preceding sunspots of the NOAA 0431 active region
Authors: Vince, O.; Vince, I.
Bibcode: 2004IAUS..223..305V
Altcode: 2005IAUS..223..305V
The spectra of the MnI 539.47 nm spectral line were observed in three
different sunspots of the NOAA 0431 active region. Perpendicularly to
the dispersion axis, the spectra were divided into several strips that
covers the quiet photosphere, penumbra and the umbra of the appropriate
sunspot. The manganese spectral line parameters variation along the
spectrograph slit were determined and analyzed.
Title: The influence of stellar effective temperature on the MnI
5394.7 Å line parameters
Authors: Vince, O.; Vince, I.
Bibcode: 2003POBeo..75...79V
Altcode:
The synthetic profiles of the MnI 5394.7 Å spectral line for
several hypothetical stars with different effective temperature are
calculated. The hyperfine structure of the manganese line is taken into
account. The parameters (equivalent width, central depth and full width
at half maximum) of these line profiles are determined. The change of
the MnI 5394.7 Å line profile parameters with effective temperature
and temperature gradients are evaluated. Using these gradients,
the temperature sensitivity of the MnI 5394.7 Å line parameters for
the solar effective temperature is determined and compared with the
corresponding observed values.
Title: The observed MnI 539.47 nm line profiles in the preceding
sunspot of the NOAA 9563 active region
Authors: Vince, I.; Ludmány, A.; Vince, O.
Bibcode: 2003POBeo..75...63V
Altcode:
The spectra of the MnI 539.47 nm line of preceding sunspot of the NOAA
9563 active region and the quiet photosphere in the vicinity of this
active region were observed. The observations were carried out with
the horizontal solar spectrograph of Heliophysical Observatory in
Debrecen on August 6, 2001. The profiles of the MnI 539.47 nm line
in the quite photosphere, umbra and in four positions in penumbra,
as well as their parameters (equivalent width (EW), central depth
(CD) and full width at half maximum (FWHM)) are determined. Relative
large increase (30-70%) of the MnI 539.47 nm line profile parameters
from quiet photosphere to umbra is obtained. The MnI 539.47 nm line
profile parameters observed in a sunspot exhibit an opposite behaviour
to those observed in solar plages.
Title: Interactive spectral analyzer and comparator (ISAAC)
Authors: Latković, O.; Cséki, A.; Vince, I.
Bibcode: 2003POBeo..75...89L
Altcode:
We are developing an application for graphical comparison of observed
and synthetic spectra (ISAAC). Synthetic spectrum calculation is
performed by SPECTRUM, Stellar Spectral Synthesis Program by Richard
O. Gray that we use with his kind permission. This program computes line
profiles under LTE conditions in the given wavelength interval using a
stellar (solar) atmosphere model, a spectral line data list (wavelength,
energy levels, oscillator strengths, and damping constants), a file
containing data for atoms and molecules, as well as a data file for
hydrogen line profiles calculation. ISAAC offers a simple interface
for viewing and changing any atomic parameter SPECTRUM uses for line
profile calculation, enabling quick comparison of the new synthetic
line profile with the observed one. In this way parameters like relative
abundances, oscillator strengths and van der Waals damping constants can
be improved, achieving a better agreement with the observed spectrum.
Title: A program for solving multi-level NLTE radiative transfer
problems
Authors: Erkapić, S.; Atanacković-Vukmanović, O.; Vince, I.
Bibcode: 2003POBeo..75...85E
Altcode:
A program for solving multi-level NLTE radiative transfer problems
in semi-infinite, plane-parallel one-dimensional atmospheres based
on the Implicit Lambda Iteration method is being developed. In this
paper the program is applied to the solution of a prototype hydrogen
lines formation problem in the solar atmosphere.
Title: The influence of hyperfine structure on the solar Mn I 543.25
nm line profile
Authors: Vitas, N.; Vince, O.; Vince, I.
Bibcode: 2003KFNTS...4..142V
Altcode:
The Mn I 543.25 nm spectral line has unusually broad line profile due to
its hyperfine structure. Here we present the results of LTE calculation
of the synthetical profile of the Mn I 543.25 nm line in the solar
spectrum. We used the Oxford total absorption oscillator strength
measurements as the first approximation for hyperfine structure. The
observed spectrum was taken from the High Resolution Solar Spectrum
Atlas. The relative intensities of six hyperfine components were varied
to obtain a good fit with the observed line profile.
Title: Center-to-limb variation of the Mn I 539.5 nm and the Mn I
543.2 nm line profiles
Authors: Vince, I.; Andriyenko, O.; Vince, O.
Bibcode: 2003KFNTS...4..138V
Altcode:
In order to find the influence of different atmospheric layers and the
granulation on profiles of Mn I 539.5/543.3 nm lines we observed them
at different heliocentric angles, theta (cos theta = 1.0, 0.82, 0.6,
0.4, 0.2). Observations were carried out on the solar telescope at the
Terskol Observatory. Full width at half maximum (FWHM), equivalent width
(EW) and central intensity of line profiles were measured. EW and FWHM
of both lines increase with heliocentric angle, while the CI decrease
for the Mn 543.3 nm line and slightly increase near the limb for the
Mn 539.5 nm line. Synthetic profiles of these lines were calculated
under LTE assumption taking into account the hyperfine structure and
compared with observed data.
Title: The influence of hyperfine structure on some manganese line
profiles in the solar spectrum
Authors: Vitas, N.; Vince, I.
Bibcode: 2003SerAJ.167...35V
Altcode:
Taking into account effects of hyperfine structure, we calculated
the synthetic solar spectrum for wavelength intervals around nine
neutral manganese lines. To estimate values of hyperfine components
we used the Oxford total absorption oscillator strength measurements
(Booth et al. 1983). We compared observed profiles (Photometric Atlas
of the Solar Spectrum from 300 to 1000 nm (Delbouille et al. 1973))
of selected manganese lines with synthesized profiles in two cases:
when hyperfine structure is not and when it is taken into account. By
comparing the calculated with observed spectrum, we corrected the
total oscillator strengths of all nine selected manganese lines.
Title: Determination of metallicity of the HR 7914 solar-like star
Authors: Vince, O.; Vince, I.
Bibcode: 2003SerAJ.167...69V
Altcode:
By using the Blackwell program package by R.O. Gray, the metallicity
of the HR7914 solar-like star was determined. The program package
utilizes measured equivalent widths of several chosen neutral iron
spectral lines from the observed spectra, appropriate atomic and
spectral line parameters and adequate Kurucz's stellar atmosphere
models. The method is based on determination of the minimum dispersion
of the iron abundance versus microturbulent velocity functions for
the selected neutral iron spectral lines. The spectra were observed
at National Astronomical Observatory Rozhen (NAO Rozhen), Bulgaria,
using the 2m-telescope and Coude spectrograph. They were reduced
with the IRAF program package. The measurement of the spectral line
parameters was done with the SPE program package. The metallicity of
the HR7914 solar-like star was determined to be 0.02.
Title: Instrumental profile of the Debrecen solar spectrograph
Authors: Murakozy, J.; Vince, I.; Ludmany, A.
Bibcode: 2003SerAJ.167...81M
Altcode:
The solar spectrograph of the Heliophysical Observatory at Debrecen,
Hungary, was investigated to determine its instrumental profile. The
measurements were made by using a HeNe laser beam. The widths and
asymmetries of the profiles decrease toward higher spectral orders,
the most advantageous orders being the third and the fourth ones. To
eliminate the broadening of solar lines on account of the instrumental
profile, the straightforward iteration method of Gurtovenko has been
applied. The efficiency of the method is demonstrated by the simulation
of the broadened and corrected spectral line profiles.
Title: Solar Mn I 5432/5395 Å line formation explained
Authors: Doyle, J. G.; Jevremović, D.; Short, C. I.; Hauschildt,
P. H.; Livingston, W.; Vince, I.
Bibcode: 2001A&A...369L..13D
Altcode:
We present a solution for the long standing problem concerning the
``chromospheric'' behaviour of the Mn i 5395/5432 Å lines in the
solar spectrum using multi-line/multi-species NLTE modelling. Using
comprehensive spectral line formation modelling, we show that the
Mn i lines are very sensitive to optical pumping in a transition
which overlaps with Mg ii k. It therefore follows that one has to be
careful with the choice of lines as temperature indicators and for
the determination of the Mn abundances although on the other hand,
due to the formation process of these lines they may be useful as a
solar and stellar activity diagnostic.
Title: An Overview of the 1999 Total Solar Eclipse Observations
in Yugoslavia
Authors: Vince, I.
Bibcode: 1999POBeo..65..201V
Altcode:
No abstract at ADS
Title: Observational programme of the August 11, 1999 total solar
eclipse
Authors: Vince, I.
Bibcode: 1999CoSka..28..260V
Altcode:
In this paper a programme for observation of the total solar eclipse
of August 11, 1999 is presented.
Title: On the solar eclipse.
Authors: Vince, I.
Bibcode: 1999Vasio..47...29V
Altcode:
The origin of solar eclipses is discussed und instructions how to
observe it are given, with special reference to the 1999 August
11 eclipse.
Title: Observational program for the total solar eclipse of August
11, 1999
Authors: Vince, I.
Bibcode: 1998ASPC..155..394V
Altcode: 1998sasp.conf..394V
No abstract at ADS
Title: On the chromospheric behaviour of photospheric MN 539.47 NM
spectral line
Authors: Vince, I.; Erkapic, S.
Bibcode: 1998IAUS..185..459V
Altcode:
The measured equivalent width of MnI 539.47 nm spectral line of the full
solar disk shows a variation of about 2% in period from 1979 to 1991
(Livingston, 1992). The equivalent width reaches its maximal value at
minimum of solar activity (1985/86). According to Livingston (1992)
this chromospheric behaviour of the MnI 539.47 nm "is a mystery to
us". We try to solve this mystery theoretically in the frame of energy
level population of the MnI atom influenced by the chromospheric flux
and the collision rate variation. Besides, we present the results of
our solar irradiance observations of MnI 539.47 nm and MnI 543.25 nm
spectral lines from 1987 to 1993. As both spectral lines have the same
lower energy level of transition the comparison of their behaviour
can help us to solve the MnI 539.47 nm spectral line enigma.
Title: Gas dynamics in the central part of the Sy 1 galaxies: III
Zw 2 and Mrk 817
Authors: Popovic, L. C.; Vince, I.; Kubicela, A.; Salim, S.
Bibcode: 1998IAUS..184..227P
Altcode:
From spectrograms of III Zw2 and Mrk 817 Sy1 galaxies observed at
Crimean Astrophysical Observatory by K. K. Chuvaev in the period 1978
-- 1991 we analysed H-β spectral line profiles. For description of
the measured line profiles we applied a model with outflow of gas and
gravitational redshift effects in broad line region.
Title: The influence of Belgrade solar spectrograph's apparatus
function on line profiles.
Authors: Vince, O.; Kubičela, A.; Vince, I.; Popović, L. Č.;
Jevremović, D.
Bibcode: 1997POBeo..57..129V
Altcode:
The apparatus function of Belgrade solar spectrograph for different
entrance slit widths is determined using the He-Ne laser 633 nm
line. CCD spectrograms of 0.25 nm wavelength interval at λ = 630 nm
were taken with different entrance slit widths. The Fourier transform
method is applied for deconvolution of corresponding instrumental
profiles. It is shown that the central intensity and the full width at
half maximum of reconstructed line profiles of strong spectral lines
do not depend on the entrance slit width, but for week spectral lines
such a dependence is evident for entrance slit widths wider than 150
μm. The equivalent with is invariant with respect to the entrance
slit width variation.
Title: Solar dynamics over cycle 19 using sunspots as tracers.
Authors: Nesme-Ribes, E.; Meunier, N.; Vince, I.
Bibcode: 1997A&A...321..323N
Altcode:
The angular velocities and meridional motions of cycle 19
sunspots observed at Meudon were investigated. We compare our
results with cycle 21 sunspot rotation properties (Nesme-Ribes et
al. 1993A&A...274..563N). We found also a complex latitudinal
meridional circulation pattern similar to what was observed on cycle
21 sunspots (Nesme-Ribes et al. 1993A&A...276..211N). We also
corroborated the very small sunspot covariance (i.e. angular momentum
transport via Reynolds stresses), which imposes a strong constraint
on the source term of the differential rotation modeling.
Title: Astrometric aspects of 1980 Indian total solar eclipse.
Authors: Protitch-Benishek, V.; Arsenijević, J.; Vince, I.; Kubičela,
A.; Lazendic, J.
Bibcode: 1997BABel.155..117P
Altcode:
During the total solar eclipse of February 16, 1980, observable from
India, besides many kinds of research programs, the sequence of eclipse
phases was taken photographically for astrometric purposes. All relevant
parameters of this eclipse are derived, including ΔT, Tmax,
ΔRS etc.
Title: Polarimetric Observations with a CCD Camera at Belgrade
Observatory
Authors: Vince, I.; Popović, L. C.; Kubičela, A.; Arsenijević, J.
Bibcode: 1997IAPPP..67...56V
Altcode:
No abstract at ADS
Title: Software for Photometric Analysis of CCD Images
Authors: Malkov, S.; Jovanović, A.; Popović, L. C.; Kubičela, A.;
Vince, I.; Arsenijević, J.
Bibcode: 1997IAPPP..67...62M
Altcode:
No abstract at ADS
Title: Optical polarization changes during the eclipse period of
VV CEP
Authors: Arsenijevic, J.; Djurasevic, G.; Markovic, S.; Vince, I.;
Kubicela, A.
Bibcode: 1997jena.confE.105A
Altcode:
Linear Optical polarization of the star VV Cep measured at Belgrade
Observatory during the period of time 1974 - 1992 ( almost 90% of or-
bital period ) is presented. Both polarization parameters vary with
orbital phases.The minimal observed values of percentage around 0.97%
(yearly means value ) fell at the instant of primary mid-totality,
photometricaly observed elswhere at the phase 0.0013, and at the time
of predicted secondary mid-totality at phase 0.4496, photometricaly not
observed. Between these small values polarization percentage increasis
continuously having maximal values of about 1.67% ( yearly means )
at the interval of the phases 0.1958-0.2077 and 0.5933-0.5965. During
these intervals of time two stars, on their apparent orbit, have the
largest distances. For the observer from the Earth two stars were
at gratest mutual elongations. The phase dependance is also found
in the position angle of polarization. Yearly mean values of the
position angles changed between 27.0 and 37.9 degrees having two maxima
apximately one year after maxima of polarization percentage. Continuous
changes of the measured angles have been interrupted two times, during
periods of primary (1976-1977) and secondary (1986) eclipses. At both
instants the position angle jumped to higher values than the values
we would expect from the continuous curve of position angle variation
in the rest of time. Besides the phase-dependent long-term changes
some short-term variations exist too. But, the number of present
observations are not sufficient for the detailed analysis. The origin
of the polrization could have three possible sources of scattering:
the light scattering on small particles in the extended atmosphere
(envelope) of M supergiant primary, on the free electrons in the B star
envelope and in the gas stream going from M to B star. In spite of so
complex scattering picture the main characteristics of polarization
variations are phenomenologically well explained.
Title: 23rd IAU General Assembly, Kyoto (Japan), 18/30
Aug 1997.
Authors: Popović, L. Č.; Vince, I.
Bibcode: 1997Vasio..45...81P
Altcode:
No abstract at ADS
Title: On the Behaviour of Photospheric MnI 539.47 NM Spectral Line
Authors: Vince, I.; Erkapic, S.
Bibcode: 1997jena.confE..62V
Altcode:
The measured equivalent width of MnI 539.47 nm spectral line of the full
solar disk shows a variation of about 2% in period from 1979 to 1991
(Livingston, 1992). The equivalent width reaches its maximal value at
minimum of solar activity (1985/86). According to Livingston (1992)
this chromospheric behaviour of the MnI 539.47 nm "is a mystery to
us". We try to solve this mystery theoretically in the frame of energy
level population of the MnI atom influenced by the chromospheric flux
and the collision rate variation.
Title: Forms and development of dark spots after SL-9 Jupiter
collision observed at Belgrade.
Authors: Kubičela, A.; Arsenijević, J.; Popović, L. Č.; Vince, I.
Bibcode: 1996POBeo..54...67K
Altcode:
A row of about 20 fragments of Comet Shoemaker-Levy (SL-9) collided
with Jupiter in July 1994. The event was observed at the Belgrade
Observatory from July 17 till August 8 - comprising the colliding
period and two weeks after the collision was ended. The Zeiss 65/1055
cm refractor with the aperture reduced to 40 cm and an SBIG professional
CCD imaging camera was used. In all 238 images of Jupiter were obtained
- mostly in the V spectral region. Here the observed shapes and some
impact spots developing tendencies are shown.
Title: Observational program for the total solar eclipse of August
11, 1999.
Authors: Vince, I.; Kubičela, A.; Arsenijević, J.; Protitch-Benishek,
V.; Popović, L. Č.
Bibcode: 1996POBeo..54..193V
Altcode:
No abstract at ADS
Title: Astronomical orientations of graves and skeletons in Gomolova
and Mokrin.
Authors: Vince, A.; Jovanović, B.; Vince, I.; Vince, O.
Bibcode: 1996POBeo..54..199V
Altcode:
The orientations of 25 skeletons in Gomolova cemetery, and 146 graves
and 171 skeletons in Mokrin cemetery has been determined. On the
basis of the presented method their angular distributions has been
studied. The authors found that the bodies at Gomolova were oriented
toward the azimuths of sunrise on the day of death or burial, while
their results for Mokrin show that the graves and skeletons were
oriented in N-S direction and it appeared that the dead faces pointed
toward the point of sunrise.
Title: A possible theoretical explanation of CCD interference
patterns.
Authors: Jankov, S.; Vince, I.; Kubičela, A.; Jevremović, D.;
Popović, L. C.
Bibcode: 1996BABel.153..115J
Altcode:
Quite high interference disturbance has been noticed in the authors'
SBIG ST-6 CCD camera when applied in solar spectrophotometry. This
behaviour has been explained quantitatively by the effect of spatial
incoherence produced by an extended light source as the sun.
Title: Microturbulent Sensitivity on some solar spectral Lines
Authors: Erkapic, S.; Vince, I.
Bibcode: 1996hell.conf...42E
Altcode:
No abstract at ADS
Title: Belgrade Observational Program for the Total Solar Eclipse
of August 11, 1999
Authors: Vince, I.; Kubicela, A.; Arsenijevic, J.; Popovic, L. C.
Bibcode: 1996RoAJ....6...99V
Altcode:
No abstract at ADS
Title: Variations of the linear optical Polarisation of 88 HER
Authors: Arsenijevic, J.; Markovic-Krsljanin, S.; Jankov, S.; Vince,
I.; Kubicela, A.; Erkapic, S.
Bibcode: 1996hell.conf..228A
Altcode:
No abstract at ADS
Title: Belgrade Observatory Experiences in Total Solar Eclipse
Observations
Authors: Vince, I.; Kubicela, A.; Arsenijević, J.
Bibcode: 1996RoAJ....6...33V
Altcode:
No abstract at ADS
Title: Lα line in the MKN335 Seyfert 1 galaxy.
Authors: Popović, L. Č.; Jevremović, D.; Vince, I.; Milovanov, T.
Bibcode: 1995POBeo..50..107P
Altcode:
The analysis of the Lα emission line profile of MKN 335 Seyfert 1
galaxy is presented. The line profile shows a prominent blue asymmetry
(A = -0.18) for description of this asymmetry a model with outflow
emission gas and gravitational redshift effect in the Broad Line Region
are applied.
Title: Analysis of the Mg II h spectral line shapes in HR 7275 and
IM Peg.
Authors: Popović, L. Č.; Vince, I.; Jankov, S.; Djurašević, G.;
Atanacković-Vukmanović, O.; Jevremović, D.
Bibcode: 1995POBeo..50..111P
Altcode:
The analysis of high-resolution IUE spectra of the RS CVn type stars HR
7275 and IM Peg is presented. The inverse method technique was applied
to the Mg II h chromospheric emission line, that shows the presence
of interstellar absorption, in order to recover the intrinsic stellar
line profile parameters.
Title: On inverse methods used at Belgrade Observatory for analysis
of spectral line shapes.
Authors: Vince, I.; Popović, L. Č.; Jankov, S.; Djurašević, G.;
Atanacković-Vukmanović, O.; Jevremović, D.
Bibcode: 1995POBeo..50...21V
Altcode:
The authors present inverse methods used for analysis of spectral line
shapes at Belgrade Observatory. A short description of the methods
and some examples of application are given.
Title: Belgrade observations of SL9 impact on Jupiter.
Authors: Popović, L. Č.; Kubičela, A.; Arsenijevič, J.;
Jevremović, D.; Vince, I.
Bibcode: 1995POBeo..49..187P
Altcode:
CCD observations of the perturbations in Jupiter's atmosphere caused
by the impact of fragments of the comet SL9 on this planet are
presented. The appearance and evolution of "dark spots" in Jupiter's
atmosphere in the V and R spectral region were recorded.
Title: Influence of photospheric parameters on solar spectral line
parameters.
Authors: Erkapić, S.; Vince, I.
Bibcode: 1995POBeo..49..159E
Altcode:
Spectral line profiles for 31 solar spectral line from the Belgrade
observational program have been synthesized previously. The authors gave
a short review on the sensivity of those spectral lines examining the
behaviour of some line profile parameters (equivalent width, central
residual flux, full-half width) induced by independent variations
of temperature, gas pressure and electron density gradient in the
atmosphere model. The results displayed as gradients of line profile
parameters have shown high sensitivity of spectral lines to the
temperature and a negligible sensitivity to the pressure and electron
density change.
Title: Some characteristics of intrinsic polarization of Be star
κ Dra.
Authors: Arsenijević, J.; Marković-Kršljanin, S.; Vince, I.;
Jankov, S.
Bibcode: 1995POBeo..49...73A
Altcode:
The intrinsic polarization parameters of κ Dra in V-color measured
at Belgrade Observatory during the 14 years period (1979 - 1992) are
presented. The changes of polarization percentage are discussed with
the data of V-color photometry and Hα emission line equivalent widths.
Title: Mg II h and k lines in the GHRS spectra of α Ori.
Authors: Jevremović, D.; Vince, I.
Bibcode: 1995POBeo..49..163J
Altcode:
The authors dearchived the echelle spectrum of α Ori from HST
archive and compared it with prediction of Basri et al. (1981) model
chromosphere.
Title: The First Hungarian-Yugoslav Astronomical
Conference. Proceedings. Conference, Baja (Hungary), 26 - 27 Apr 1995.
Authors: Vince, I.; Dimitrijević, M. S.; Balázs, L.
Bibcode: 1995POBeo..49.....V
Altcode:
These proceedings are a kind of "catalogue" of astronomical activities
in Yugoslavia and Hungary.
Title: The Belgrade observations of Jupiter during the period of
its colliding with SL-9 comet.
Authors: Popović, L. Č.; Kubičela, A.; Arsenijević, J.;
Jevremović, D.; Vince, I.
Bibcode: 1995BABel.151...85P
Altcode:
The authors present results of CCD observations of the perturbations
in Jupiter's atmosphere caused by the impact of fragments of comet
SL-9 on this planet. The appearance and evolution of "dark spots"
in Jupiter's atmosphere were recorded in V and R spectral region.
Title: Changes in the low dispersion IUE spectra of μ Cep.
Authors: Jevremović, D.; Vince, I.
Bibcode: 1995BABel.151...75J
Altcode:
The authors analysed low dispersion IUE spectra of the cool dusty
supergiant μ Cep observed from 1979 to the end of 1989. They have
found changes of "active regions" and continua's flux in these spectra
similar to variations of the optical linear polarization degree during
this period.
Title: On the average optical depths of formation of some Fraunhofer
lines.
Authors: Erkapić, S.; Vince, I.
Bibcode: 1995BABel.151...13E
Altcode:
Average optical depths of the line depression formation in the center
of the solar disk for eighteen selected Fraunhofer lines have been
calculated for six solar atmosphere models given by Vernazza et
al. (1981). Some regularities in the behavior of the average optical
depths vs. central residual intensities of the line profiles and lower
level excitation potential have been examined.
Title: Polarization Measurements of Some Be Stars
Authors: Vince, I.; Arsenijević, J.; Marković-Kršljanin, S.;
Jankov, S.; Skuljan, Lj.
Bibcode: 1995IAPPP..59...32V
Altcode:
No abstract at ADS
Title: Belgrade Astronomical Observatory observation of Jupiter
during and after SL-9 comet impact time.
Authors: Popović, L. Č.; Kubičela, A.; Arsenijević, J.;
Jevremović, D.; Vince, I.
Bibcode: 1995ESOC...52..351P
Altcode: 1995esl9.conf..351P; 1995eslj.work..351P
The observations were carried out with a CCD imaging camera at Belgrade
Observatory from 17th July till 8th August covering the impact period
and 17 days after it - until the visibility of Jupiter became poor.
Title: Contribution of gravitational redshift to spectral line
profiles of Seyfert galaxies and quasars.
Authors: Popovic, L. C.; Vince, I.; Atanackovic-Vukmanovic, O.;
Kubicela, A.
Bibcode: 1995A&A...293..309P
Altcode:
In the present work we analyse the influence of gravitational field
on the profile of spectral lines. For kinematically very composite
regions near nuclei of Seyfert galaxies and quasars both the optically
thin and optically thick cases have been considered. We suppose that
the line profile without gravitational field influence (undisturbed
profile) is a Voigt one. Irrespective of any other (mostly Doppler)
influence the gravitational one yields shifted and asymmetric, and
under the assumption of optically thin region, broadened spectral
lines. The blue wing of the deformed spectral line is lower, while
the red one is higher than in the undisturbed line profile. In the
case of optically thin region we have discussed the shape of spectral
lines for different wavelength ranges.
Title: Mg II h and k lines in the IUE spectra of the cool dusty
supergiant μ Cep.
Authors: Jevremović, D.; Vince, I.
Bibcode: 1994BABel.150...41J
Altcode:
The authors present results of investigation of the Mg II h and k lines
in the IUE archive high resolution spectra of cool dusty supergiant
μ Cep. They found the total chromospheric radiative loss, and showed
that existing chromospheric models are not usable for very dusty stars
as μ Cep.
Title: Interference fringes of a CCD camera.
Authors: Kubičela, A.; Jevremović, D.; Popović, L. Č.; Skuljan,
J.; Arsenijević, J.; Vince, I.
Bibcode: 1994BABel.150...37K
Altcode:
Very high interference disturbance has been noticed in a SBIG ST-6
CCD camera when applied in solar spectrophotometry. The interference
fringes have been removed by tilting the plane of the CCD receiver
with respect to the optical axis of the spectrograph Littrow lens.
Title: Contribution of gravitational redshift to spectral line
profiles of AGN: the case of Lorentzian profile.
Authors: Popović, L. Č.; Vince, I.; Kubičela, A.;
Atanacković-Vukmanović, O.; Samurović, S.
Bibcode: 1994BABel.149....9P
Altcode:
The authors analyse the influence of gravitational redshift on the
spectral line profiles of homogeneous, static and optically thin region
near massive AGN (Seyfert galaxies and quasars). The correction function
that determines the degree of spectral line profile distorsion produced
by gravitational field has been investigated.
Title: Influence of the gravitational field on the shape of spectral
lines in spectra of Seyfert galaxies and quasars.
Authors: Popović, L. C.; Vince, I.; Kubičela, A.
Bibcode: 1994IAUS..159..456P
Altcode:
No abstract at ADS
Title: Stark Broadening of Znii and Cdii Spectral Lines of
Astrophysical Interest
Authors: Popovic, L. C.; Vince, I.; Dimitrijevic, M. S.
Bibcode: 1993A&AS..102...17P
Altcode:
Using a modified semi-empirical approach, Stark broadening parameters
for 12 Zn II and 8 Cd II spectral lines have been calculated as a
function of temperature. The results obtained have been compared
with available experimental data. The influence of the oscillator
strengths accuracy on Stark broadening parameter calculation has
been investigated.
Title: Behavior of some Fraunhofer lines around maximum of solar
activity.
Authors: Skuljan, J.; Kubičela, A.; Vince, I.; Arsenijević, J.;
Popović, L. C.
Bibcode: 1993POBeo..44...37S
Altcode:
Equivalent widths of 18 Fraunhofer lines have been observed in
integrated solar light from 1987 till 1992. Sixteen more dependable
spectral lines out of 18 measured ones exhibit an extreme value
(maximum or minimum) near the maximum of solar activity cycle.
Title: Influence of temperature gradient changes on solar spectral
line profile parameters.
Authors: Erkapić, S.; Vince, I.
Bibcode: 1993POBeo..44...29E
Altcode:
The authors examine, theoretically, the influence of temperature
gradient changes on 27 spectral line profiles.
Title: The center-to-limb variations of some solar spectral line
parameters.
Authors: Jevremović, D.; Vince, I.; Erkapić, S.; Popović, S.
Bibcode: 1993POBeo..44...33J
Altcode:
A statistical analysis of center-to-limb changes in equivalent widths
and coefficients of asymmetry and excess of 83 Fraunhofer lines
was made.
Title: Spectrum of CP stars: Stark width of heavy ion lines.
Authors: Popović, L. C.; Dimitrijević, M. S.; Vince, I.
Bibcode: 1993POBeo..44...55P
Altcode:
The authors present the results of their investigation of Stark
broadening for a number of astrophysically important heavy ion lines
in order to provide the corresponding Stark broadening data needed
for astrophysical purposes.
Title: On the swimming out of the solar magnetic tubes.
Authors: Tomić, A.; Vince, I.
Bibcode: 1993POBeo..44..128T
Altcode:
No abstract at ADS
Title: Solar dynamics over solar cycle 21 using sunspots as
tracers. II. Meridional motions and covariance.
Authors: Nesme-Ribes, E.; Ferreira, E. N.; Vince, I.
Bibcode: 1993A&A...276..211N
Altcode:
Meridional motions of sunspots observed at Meudon were investigated for
the period 1977-1984. A complex time and latitude-dependent meridional
circulation was found, though the signal remains hardly above the 2σ
level, when data are averaged over the full solar cycle. The latitudinal
transport of linear angular momentum by sunspots was also estimated. The
main results are that meridional motions share in the modulation of the
differential rotation amplitude through the 11 -y cycle, the horizontal
momentum transport, via Reynolds stresses, seems to be absent. These
findings shed doubt on the origin of the differential rotation.
Title: Long-term changes of equivalent widths of ten selected
Fraunhofer lines.
Authors: Vince, I.; Kubičela, A.; Skuljan, J.; Karabin, M.;
Erkapić, S.
Bibcode: 1993sova.conf...74V
Altcode:
The results confirm that equivalent widths of some spectral lines
change with time probably due to they sensitiveness to solar activity.
Title: Spectral analysis of a white-light flare
Authors: Sotirovski, P.; Boyer, R.; Hiei, E.; Vince, I.
Bibcode: 1992A&A...262..597S
Altcode:
A flare phenomenon was observed on 26 September 1963 at the Crimean
Astrophysical Observatory. Using an echelle spectrograph the flare
spectra from 3500 to 6700 were obtained with a dispersion of 0.56
to 0.30 A/mm. The flare lasted from 06:38 UT to 09:24 UT, with the
maximum at 07:21 UT and located N 15, W 75. Twenty spectra were
recorded during the flare. Our analysis concerns only seven time
sequences which were chosen according to the quality of the spectra;
among them four belong to the earlier phase. The line profiles and the
halfwidths of the Balmer series from H-alpha to H(14) were measured in
order to obtain electron density by using Stark broadening, and the
continuum intensity as a function of wavelength is studied in order
to deduce the emission mechanism.
Title: Solar activity influence on equivalent widths of some
photospheric lines.
Authors: Skuljan, J.; Karabin, M.; Vince, I.; Kubicela, A.
Bibcode: 1992BABel.145....1S
Altcode:
Changes of equivalent widths for ten selected spectral lines (530.74
nm ≤ λ ≤ 568.82 nm) were evaluated according to "Belgrade Program
for Monitoring of Activity-Sensitive Spectral Lines of the Sun as a
Star". Observations from August 1987 till May 1990 have been processed
in the way for the first time presented here.
Title: The data processing in solar spectrophotometry.
Authors: Skuljan, J.; Erkapić, S.; Vince, I.; Kubičela, A.
Bibcode: 1992BABel.145..157S
Altcode:
An interactive software package especially developed for solar
spectrophotometry at the Belgrade Astronomical Observatory is
described. The programs are written to automate the measuring procedure
in Belgrade Program for Monitoring of Activity-Sensitive Spectral Lines
of the Sun as a Star. The procedure includes the flat field reduction,
correction of the X-scale, normalization to the continuum level,
and evaluation of equivalent widths.
Title: Fe I line asymmetries and shifts caused by pressure broadening
Authors: Kršljanin, V.; Vince, I.; Erkapić, S.
Bibcode: 1991LNP...380..277K
Altcode: 1991IAUCo.130..277K; 1991sacs.coll..277K
In order to test the validity of the usual neglect of pressure
line shifts in investigations of Fe I line asymmetries and shifts,
we calculated synthetic line bisectors and shifts of 96 moderate
and weak photospheric lines, taking into account both hydrogen- and
electron-impact shifts and neglecting the velocity fields. Absolute
pressure line shifts obtained are less than or appr. equal to 50 m/s
and the largest relative shifts along the bisectors are about 40m/s. We
found pronounced dependences of both shifts and bisectors on the energy
of the upper level in transitions and on the transition array.
Title: Solar Rotation Over SOLAR-CYCLE-21
Authors: Ribes, Elisabeth; Vince, Istvan; Mein, Pierre; Neto Ferreira,
Eduardo
Bibcode: 1991LNP...380..241R
Altcode: 1991sacs.coll..241R; 1991IAUCo.130..241R
Having measured the rotation rate of sunspots through solar cycle 21,
from 1977 to 1983, we have found that the mean differential rotation
averaged over this seven year record is similar to the grand average
differential rotation determined by Howard et al. (1984) over the
period 1921-1982. However, the rotation rate does change from year to
year. These changes are evidenced by a steepening or a flattening of
the mean differential rotation profile, as well as significant changes
in the equatorial rate. The presence of a time-dependent pattern of
azimuthal roils inferred from the meridional circulation pattern of
the sunspots offers a qualitative explanation of the observed rotation
rates. The amplitude of the changes is almost one order of magnitude
larger than that of the torsional oscillations found by Howard and
LaBonte (1981).
Title: Activity Cycle Variation of Some Photospheric Lines
Authors: Karabin, M.; Kubičela, A.; Skuljan, J.; Vince, I.
Bibcode: 1990PDHO....7..104K
Altcode: 1990ESPM....6..104K; 1990dysu.conf..104K
No abstract at ADS
Title: Investigation of the collisional limb effect and shape of
solar spectral lines at the Astronomical Observatory in Belgrade.
Authors: Vince, I.
Bibcode: 1989BOBeo.140..117V
Altcode:
The author investigates the absorber-perturber collision effects on
the solar limb effect and on spectral line profiles.
Title: Long-term changes of linear optical polarization of Be stars.
Authors: Arsenijević, J.; Jankov, S.; Djurašević, G.; Vince, I.
Bibcode: 1989BOBeo.140....1A
Altcode:
First results of ten-year optical polarization measurements of ο And,
88 Her, κ Dra, and γ Cas are given. The existence of slow changes of
polarization parameters has been asteblaihes in all four stars. For
two of them, 88 Her and κ Dra, the intrinsic polarization has been
determined.
Title: Pressure Broadening and Solar Spectral Line Bisectors
Authors: Vince, I.; Dimitrijević, M. S.
Bibcode: 1989ASIC..263...93V
Altcode: 1989ssg..conf...93V
No abstract at ADS
Title: On the oscillation of the solar diameter.
Authors: Ribes, Elizabeth; Ribes, Jean-Claude; Vince, Istvan; Merlin,
Philippe
Bibcode: 1988CRASB.307.1195R
Altcode: 1988CR2...307.1195R; 1988CR....307.1195R
Systematic visual measurements of the solar diameter (both polar and
equatorial) made with the meridian circle have been carried out at the
Belgrade astronomical observatory, from 1975. The measurements indicate
an oscillation similar to that obtained by Laclare with the astrolabe
measurements, i.e. a similar period, phase and amplitude. This result
confirms the solar (or terrestrial atmosphere) nature of the observed
oscillation, thus eliminating the personal equation and instrumental
biases.
Title: Be stars - a challenge to the observers and theoreticians.
Authors: Arsenijević, J.; Kubičela, A.; Vince, I.
Bibcode: 1988BOBeo.138...31A
Altcode: 1988BARB..138...31A
No abstract at ADS
Title: Belgrade program for monitoring of activity - sensitive
spectral lines of the sun as a star. II. Selection of Fraunhofer
lines and beginning of a study of their long-term changes.
Authors: Vince, I.; Kubičela, A.; Arsenijević, J.
Bibcode: 1988BOBeo.139...25V
Altcode: 1988BARB..139...25V
No abstract at ADS
Title: Belgrade program for monitoring of activity-sensitive spectral
lines of the Sun as a star. I. An analog solar scanning monochromator.
Authors: Arsenijević, J.; Kubičela, A.; Vince, I.; Jankov, S.
Bibcode: 1988BOBeo.138....1A
Altcode: 1988BARB..138....1A
No abstract at ADS
Title: A survey of historical and recent solar diameter observations
Authors: Ribes, E.; Ribes, J. C.; Vince, I.; Merlin, Ph.
Bibcode: 1988AdSpR...8g.129R
Altcode: 1988AdSpR...8..129R
We report new observational evidence of periodic changes in the solar
diameter. Progress has been made at two levels: Systematic
measurements of the solar diameter (both horizontal and vertical)
have been made using a Meridian Circle at the Belgrade Observatory,
from 1974 to 1986. An oscillation (amplitude of +/-0.20 arcsec, period
of about 900 days) is present in both diameters. Although the data
are fewer and noisier than the astrolabe measurements made by Laclare
(1987), they provide an independent confirmation of the presence of
the damped oscillation reported by Delache et al. (1985), with the
same phase, period and amplitude. A Fourier analysis of the solar
diameters observed by La Hire (6,797 values), from 1683 to 1718, has
been made. The analysis exhibits a number of peaks, all of which are
present in the power spectrum of modern diameter data. In particular,
a peak at 9,6 years is clearly visible. This result indicates that the
solar cycle occured during the Maunder minimum, although the dearth of
sunspots at the solar surface is confirmed. Some possible implications
of these findings are suggested with respect to climatic variability
on Earth.
Title: Optical polarization changes of 88 Her in the period 1974
- 1985.
Authors: Arsenijević, J.; Jankov, S.; Vince, I.; Durašević, G.
Bibcode: 1987BOBeo.137...49A
Altcode: 1987BARB..137...49A
No abstract at ADS
Title: Collision broadening and microturbulence sensitivity of some
Na I non-resonant lines.
Authors: Kršljanin, V.; Vince, I.
Bibcode: 1986BOBeo.136...12K
Altcode: 1986BARB..136...12K
No abstract at ADS
Title: Uticaj sudarnih procesa na Limb-efekt Title: Uticaj sudarnih
procesa na Limb-efekt Title: The influence of impact processes on
the limb effect;
Authors: Vince, Ištvan
Bibcode: 1986PhDT........43V
Altcode:
No abstract at ADS
Title: Further Belgrade results of the large-scale photospheric
velocity research.
Authors: Kubičela, A.; Karabin, M.; Vince, I.; Ivanović, Z.
Bibcode: 1986BOBeo.136....1K
Altcode: 1986BARB..136....1K
No abstract at ADS
Title: Variations of the linear optical polarization of κ Draconis.
Authors: Arsenijević, J.; Jankov, S.; Djurašević, G.; Vince, I.
Bibcode: 1986BOBeo.136....6A
Altcode: 1986BARB..136....6A
No abstract at ADS
Title: Pressure broadening and solar limb effect.
Authors: Vince, I.; Dimitrijevic, M. S.; Krsljanin, V.
Bibcode: 1985ASIC..152..373V
Altcode: 1985rst..conf...97V
The pressure broadening contribution to the solar limb effect is
discussed for the case of a spectral series using the Na I 3p-ns
and 4p-ns series as an example. It is found that the influence of
the pressure broadening on the solar limb effect is reduced due to
different signs of hydrogen and electron impact shifts.
Title: Correction to the solar line-of-sight velocities for
topocentric motion of the observer.
Authors: Ivanović, Z.; Vince, I.
Bibcode: 1985POBeo..33...19I
Altcode:
A method for determining the radial velocity of an observer moving
around the sun is described. The Julian date (JD) as a unique
independent variable is used. The method is developed for the reduction
of data obtained at Belgrade Astronomical Observatory in the course
of the solar spectral line shift observations. The accuracy is about
±0.1 m/s.
Title: Collision broadening and solar limb effect: Na I 3p2Po-ns2S
lines
Authors: Vince, Istvan; Dimitrijevic, Milan S.; Krsljanin, V.
Bibcode: 1985sls3.conf..649V
Altcode:
No abstract at ADS
Title: Influence of different line broadening mechanisms on the
limb-effect within Na I (4s2S-np2P0)
series.
Authors: Vince, I.; Dimitrijević, M. S.
Bibcode: 1985POBeo..33...15V
Altcode:
Line broadening parameters within Na I
(4s2S-np2P0) series have been
calculated as a function of the position angle of the observed point
on the sun. The influence of neutral atom impact-, and Stark broadening
on the limb-effect are analyzed.
Title: Effects of extrafocal observation with the solar spectrograph
of the Belgrade Astronomical Observatory. I. Solar rotation
line-of-sight velocities.
Authors: Kubičela, A.; Vince, I.
Bibcode: 1983BOBeo.133....1K
Altcode:
No abstract at ADS
Title: On the telluric lines position instability.
Authors: Vince, I.
Bibcode: 1983BOBeo.133....5V
Altcode:
No abstract at ADS
Title: Surprisingly High Optical Polarization of mu Cephei
Authors: Arsenijevic, J.; Kubicela, A.; Vince, I.
Bibcode: 1980IBVS.1859....1A
Altcode:
No abstract at ADS
Title: Some aspects of telluric line displacements in the solar
spectrum.
Authors: Vince, I.
Bibcode: 1979POBeo..26..167V
Altcode:
No abstract at ADS
Title: Some light polarization changes of omicron And.
Authors: Arsenijevic, J.; Vince, I.; Kubicela, A.
Bibcode: 1979POBeo..26..125A
Altcode:
No abstract at ADS
Title: Astronomical ephemerides for the year 1980.
Authors: Vince, I.; Stevanovic, K.
Bibcode: 1979Vasio..27...83V
Altcode:
No abstract at ADS
Title: Astronomical ephemerides for the year 1979.
Authors: Trajkovska, V.; Vince, I.
Bibcode: 1978Vasio..26...98T
Altcode:
No abstract at ADS
Title: On the Maunder minimum.
Authors: Vince, I.
Bibcode: 1978Vasio..26...57V
Altcode:
No abstract at ADS
Title: Patrol observations of AD Leo during 1976.
Authors: Arsenijevic, J.; Kubicela, A.; Vince, I.
Bibcode: 1978BOBeo.129...29A
Altcode:
No abstract at ADS
Title: Optical polarization of V1500 Cyg
Authors: Arsenijevic, J.; Vince, I.
Bibcode: 1977AZh....54..653A
Altcode:
No abstract at ADS
Title: Optical polarization of V1500 Cyg
Authors: Arsenijevic, J.; Vince, I.
Bibcode: 1977SvA....21..370A
Altcode:
No abstract at ADS
Title: Jedna graficka metoda za odredivanje azimuta izlaza i zalaza
Sunca (A graphical method for determination of the azimuth of sunrise
and sunset.).
Authors: Vince, I.
Bibcode: 1977Vasio..25...66V
Altcode:
No abstract at ADS
Title: Patrol observations of AD Leo and EV Lac during 1974 and 1975.
Authors: Arsenijevic, J.; Kubicela, A.; Vince, I.
Bibcode: 1976BOBeo.127....9A
Altcode:
No abstract at ADS
Title: Photoelectric observations of some flare stars during 1972.
Authors: Arsenijevic, J.; Kubicela, A.; Vince, I.
Bibcode: 1975BOBeo.126...54A
Altcode:
No abstract at ADS
Title: The procedure of the treatment of polarimetric measurements
with the photoelectric polarimeter of the Belgrade Astronomical
Observatory.
Authors: Vince, I.
Bibcode: 1975BOBeo.126...59V
Altcode:
No abstract at ADS
Title: The determination of the theoretical value of the degree of
polarization of the calibrator of the photoelectric polarimeter of
the Belgrade Astronomical Observatory.
Authors: Vince, I.
Bibcode: 1975BOBeo.126...56V
Altcode:
No abstract at ADS
Title: Photoelectric observations of UV Ceti stars during 1973.
Authors: Arsenijevic, J.; Kubicela, A.; Vince, I.
Bibcode: 1975BOBeo.126...55A
Altcode:
No abstract at ADS
Title: Photoelectric Observations of EV Lac during the 1973
International Patrol
Authors: Arsenijevic, J.; Kubicela, A.; Vince, I.
Bibcode: 1974IBVS..866....1A
Altcode:
No abstract at ADS