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Author name code: wildt
ADS astronomy entries on 2022-09-14
author:"Wildt, Rupert"
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Title: Spectra of Four Outer Planets
Authors: Wildt, R.
1982SciAm.247...11W Altcode:
No abstract at ADS
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Title: Physical properties of giant planets
Authors: Wildt, R.
1974STIN...7518136W Altcode:
The chemical identification and physical nature of giant planets are
discussed. The phase equilibria of H2-He mixture is briefly described
for these large planets.
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Title: Thermodynamics of the Gray Atmosphere.IV. Entropy Transfer
and Production
Authors: Wildt, Rupert
1972ApJ...174...69W Altcode:
In strict radiative equilibrium, i.e., if heat transport by conduction
and convection is negligible, the local rate of entropy production must
equal the divergence of the net flux of radiant entropy. Verification
that this divergence is positive for LTE, is straightforward even in
the nongray case. Entropy production throughout the interior can,
in the absence of mass ejection, be disposed of only by the flux
of radiant entropy escaping at the stellar surface, to which there
is an (unattainable) upper limit depending solely on the effective
temperature, namely, the entropy loss from the surface of an isothermal
blackbody radiating at the same temperature. In effect, irrespective of
grayness, the steady-state global rate of entropy production is bounded.
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Title: Hydrogen planets and high-pressure physics
Authors: Wildt, Rupert
1972PEPI....6....1W Altcode:
No abstract at ADS
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Title: The outer planets: Some early history.
Authors: Wildt, R.
1969JAtS...26..795W Altcode:
No abstract at ADS
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Title: Yale University Observatory, New Haven, Connecticut. Report
1967-1968.
Authors: Wildt, R.
1969BAAS....1..134W Altcode:
No abstract at ADS
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Title: Etude Physique des Planètes et des Satellites (Physical
Study of Planets and Satellites)
Authors: Wildt, R.
1968IAUTB..13...94W Altcode:
No abstract at ADS
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Title: Thermodynamics of the Gray Atmosphere. III. Entropy Defect
and Source Function
Authors: Wildt, Rupert
1966ApJ...146..418W Altcode:
The total entropy of a pencil of non-equilibrium radiation falls
short of the entropy maximum associated with equilibrium radiation
of the same total energy as that of the pencil (entropy defect of
nonequilibrium radiation). For the source function an entropy defect
can likewise be defined, and its integral over the entire atmosphere,
called "global entropy defect," affords a measure of the over-all
departure from LTE. In a gray atmosphere, minimizing the global entropy
defect of the source function, with proper constraints, generates the
spectrum of a source function conforming to the non-degenerate case
of Bose-Einstein statistics. It attains at the surface the maximum
departure from a Planck function, to which it tends monotonically with
increasing optical depth. A physical interpretation of Hopf's function
q(r) is given in the Appendix.
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Title: Thermodynamics of the Gray Atmosphere. II. Unattainability
of Detailed Balancing
Authors: Wildt, Rupert
1966ApJ...143..363W Altcode:
In a gray atmosphere in local thermodynamic equilibrium all pencils
of radiation are bluer than equilibrium radiation of matching total
energy; and the divergence of the net flux of photons is positive at
all depths-to the effect that radiation transmitted suffers cumulative
reddening and that the rates of inverse atomic processes of interaction
between gray matter and off-equilibrium radiation cannot balance. The
unattainability of detailed balancing conforms to principles of kinetics
(Einstein relations, etc.) holding irrespective of grayness. While
under non-gray conditions it would be difficult to ascertain the sign
of the divergence of the photon net flux, a sufficient condition for
its positivity in the gray case is the monotone approach to asymptotic
thermodynamic equilibrium at great depth.
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Title: The greenhouse effect in a gray planetary atmosphere
Authors: Wildt, Rupert
1966Icar....5...24W Altcode:
Hopf's analytical solution is illustrated for several values of the
greenhouse parameter, i.e., the ratio of gray absorption coefficients
for insolating and escaping radiation, assumed to be constant at
all depths.
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Title: Thermodynamics of the Gray Atmosphere. I. Reversible Adiabatic
Processes.
Authors: Wildt, Rupert
1964ApJ...140.1343W Altcode:
For every pencil of radiation inside a gray atmosphere in strict
radiative equilibrium, energy spectra characteristic of different net
fluxes (effective temperatures) are linked by a certain similarity
transformation if the source function, which need not be Planckian,
undergoes the same transformation. Related transformations hold for the
concomitant variations of the spectra of radiant entropy. The common
physical correlates of these similarity laws are quasi-statical
processes taking the radiation field of the gray atmosphere, a
non-equilibrium system, from one steady state to another. Because
they satisfy all appropriate criteria, it is well within the bounds of
accepted usage to call them reversible adiabatic processes, a term that
classical thermodynamics had reserved for passages through a sequence
of equilibrium states.
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Title: The Atmosphere of Jupiter
Authors: Wildt, R.
1964oeao.conf..304W Altcode:
No abstract at ADS
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Title: Thermodynamics of the Gray Atmosphere.
Authors: Wildt, Rupert
1963AJ.....68Q.547W Altcode:
The classical problem in radiative transfer is to find the
source function sustaining strict radiative equilibrium in a
gray atmosphere. That restriction, owing to the linearity of the
monochromatic transfer equation, has made it possible to detach
study of the conservation of radiant energy from inquiry into its
spectral composition. The latter commences with an appeal to Planck's
generalization, for nonequilibrium radiation, of Wien's displacement
law. For every pencil of radiation inside a gray atmosphere in strict
radiative equilibrium, energy spectra characteristic of different
effective temperatures (net fluxes) are linked by a certain similarity
transformation, provided that the source function, which need not
be Plauckian, undergoes the identical transformation; and vice
versa. Analogous displacement laws hold for the concomitant changes
in spectral distribution of radiant entropy and of the entropy source
function. The physical correlate these similarity laws have in common
are quasistatical processes that convey, by a finite change of the net
flux, the radiation field of the gray atmosphere, i.e., a nonequilibrium
system, from one steady state to another. Because they satisfy
all appropriate criteria, it is well within the bounds of accepted
usage to call them reversible adiabatic processes, a term reserved in
classical thermodynamics for passage through a sequency of equilibrium
states. The complete distribution, throughout a gray atmosphere, of
the spectrum of the source function accrues from a tentative extremum
principle replacing arguments from thermostatics. Minimization of the
global entropy deficit of the source function (a quantity identically
nought in LTE), under the constraints that strict radiative equilibrium
is preserved at all levels and that the photon flux escaping at the
surface remains invariant, yields the Kothari-Singh function. It
differs from the Plauck function by an additive parameter related to
the nonvanishing free enthalpy of nonequilibrium radiation. Since
the new parameter varies proportional to the second exponential
integral of the optical depth, LTE is reached asymptotically. This
event dispos&s of a conjecture (Wildt, R., Astrophys. J. 123,115,
1956) which had left the march of the parameter undetermined.
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Title: Planetary Interiors; rapport introductif
Authors: Wildt, R.
1963LIACo..11...15W Altcode:
No abstract at ADS
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Title: The Gray Planetary Atmosphere.
Authors: Wildt, Rupert
1961AJ.....66S.298W Altcode:
The problem of strict radiative equilibrium in a gray planetary
atmosphere of infinite depth was formulated by Milne (1922) as an
inhomogeneous integral equation. Its solution (Hopf 1934) can be
expressed in terms of Chandrasekhar's H function and an integral over
Hopf's q function. The temperature distribution, as function of the
optical depth below the surface, has been evaluated numerically for
several values of the angle of incidence of the insolating flux. Hopf's
analytical solution also holds, after application of certain scale
factors, for the temperature distribution in an atmosphere whose gray
absorption coefficient for the incident solar radiation differs from
that for the (infrared) planetary radiation, the ratio of the two
coefficients being constant throughout the atmosphere. Even this
generalization affords but a poor model of the familiar planetary
atmospheres in their present state. Nevertheless, it deserves to be
known more widely; for it is, to date, the only problem in planetary
radiative equilibrium that has been solved rigorously.
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Title: Planetary Interiors
Authors: Wildt, Rupert
1961plsa.book..159W Altcode:
No abstract at ADS
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Title: Molecules and Late-Type Stellar Models.
Authors: Vardya, M. S.; Wildt, Rupert
1960ApJ...131..448V Altcode:
A difficulty encountered by Osterbrock, when he tried to identify
particular red dwarf stars by interpolating between his models of
late-type maIn-sequence stars, is shown to be alleviated by including
the effects produced by hydrogen molecules in the convective zone.
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Title: A search for airborne particles of meteoritic origin
Authors: Hodge, P. W.; Wildt, R.
1958GeCoA..14..126H Altcode:
A year-long programme involving daily collections of atmospheric dust
at several widely separated, isolated sites has been undertaken with
the object of identifying particles that may be of extraterrestrial
origin. The particles in question are opaque, shiny spherules with
diameters less than 15 μ. They appear to be of a nature entirely
different from that of the larger spheres abounding in densely populated
areas. Their meteoritic origin is suggested by recent evidence regarding
ablation of meteorites and by the fact that the rate of fall and the
frequency distribution with size of these particles have been found
to be the same at the various stations. The average rate of fall
for each station was 1·1 spherules greater than 3 μ in diameter/cm
<SUP>2</SUP>/day. Assuming that the density of the counted particles
is that of magnetite, this rate corresponds to an annual accretion for
the entire earth of about 5 × 10 <SUP>8 kg</SUP> of these particles.
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Title: Inside the Planets
Authors: Wildt, Rupert
1958PASP...70..237W Altcode:
No abstract at ADS
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Title: Molecules in Stars: Theoretical Aspects. Introductory Report.
Authors: Wildt, Rupert
1957LIACo...7..319W Altcode:
No abstract at ADS
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Title: Radiative Transfer and Thermodynamics.
Authors: Wildt, Rupert
1956ApJ...123..107W Altcode:
The irreversibility of radiative transfer is made manifest by analyzing
the steady-state interaction of the nonisotropic field of nonequilibrium
radiation with an isotropic atom gas. It is shown that the practice of
substituting the Planck function for the source function contravenes
the second law of thermodynamics. Consideration of the nonequilibrium
entropy leads to rather general conjectures regarding the spectral
distribution of the source function.
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Title: On the Difference in Chemical Composition Between - and
Low-Velocity Stars.
Authors: Schwarzschild, M.; Spitzer, L., Jr.; Wildt, R.
1951ApJ...114..398S Altcode:
The spectroscopic peculiarities of highwelocity of the CH bands and
weakening of the CN bands and of the metal lines-can tentatively be
explained by a general reduction in the abundance of the heavy elements
and a somewhat lesser reduction in the abundance of the medium-heavy
elements, relative to the abundances for low-velocity stars. As a
working hypoQhesis, it is proposed that such a general difference in
chemical composition between stars of populations I and II stems from
the preferential accumulation of grains in the denser interstellar
clouds from which the star of population I might be formed. The
astrophysical discussion indicates that the dissociation energy of
the molecules N2 and CO should be close to 9.5 e.v.; the considerably
lower or higher values still advocated by some spectroscopists are
not supported by the astronomical evidence.
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Title: New emission lines in M dwarfs.
Authors: Wildt, Rupert
1951AJ.....56S..51W Altcode: 1951AJ.....56...51W
A number of ultraviolet spectra of K and M dwarfs were obtained with
the Qf/2 camera, dispersion about 65A/mm at X325o, attached to the
spectrograph of the 8 -inch McDonald reflector. The exposure times
were chosen as long as feasible, in order to record the ultraviolet
at wave lengths less than X35oo. A cursory inspection of the first
exposure of the star BD 2002465 (dM4e) revealed 3 emission lines
below X33oo, where the continuum of the star had already faded out;
their existence was confirmed by a second exposure. Bright lines
of HI and CaiI had been noticed in this star by Swings and Struve,1
and recently it has become famous as a flare-star.2 No photoelectric
magnitudes were recorded at Lick during the nights the spectrograms
were taken at McDonald, 1950 February 5, 8:oI U.T. and February 7,
6:56 U.T. Since Swings and Struve had stressed the similarity of the
emission spectra of BD 2002465 and YY Gem, this star too was examined
for emissions in the far untraviolet. Only one spectrogram with an
exposure time of 6 hours is available. It shows the continuum extending
to about 3250, making it more difficult to disentangle faint emission
lines. Omitting two doubtful ones, 6 emission lines were recognized
in BD 2002465 and 4 of these also appear in YY Gem. However, their
character is quite different in these two stars. In BD 2002465 the
emission lines stand out 556 1/2 5.56 3/2 13/2,2 4.63 5.53 7/53/2 z4D0
4.62 549 z6D0 5/2 4.60 7/2 ~4175 9/2 i5 1.69 Figure. 1/32/ 1.09 1.66
~3/29 4 2 1.07 a4D 3/71/3 1.04 0.96 Fell emissions in M dwarfs. lines
observed in BD +20e2465, Q lines observed in VY Gem (Castor C). sharply
against the background fog, and there is no doubt about their nature
as "lines"; an exception is the rather diffuse emission at X3228
where there is some vignetting by the spectrograph. In YY Gem the
emissions are quite diffuse. In particular, X3256 looks nearly 2A wide;
and X3278 appears unsymmetrical, the continuous background being of
different density to the red and ultraviolet of this line, as if the
emission line coincided with the edge of an absorption band degraded
toward th ultraviolet. It is fair to say that the existence of these
emissions in YY Gem could hardly have been established from a single
spectrogram if it had not been for for their previous discovery in
BD 2002465. All the lines were identified with the strongest members
of two low-excitation multiplets in the spectrum of Fell; they are
entered in the term diagram shown in the figure, which also contains
the appropriate excitation potentials. The same two multiplets of Feii,
including their fainter members, appear in emission in a Herculis
(M ) and a Scorpii (MI), according to G. Herzberg's observations.1
He proved that Feii emission does not originate in the atmospheres
of the early-type companions of these stars, but is characteristic of
the giants themselves, which also have bright H and K lines. Herzberg
also lists 8 unidentified emissions; one of them, at X329o.I5, may be
identical with a doubtful emission at X3290.o in BD 2002465. Both a
Herculis and a Scorpii have also bright H and K lines. Thus there is
suggested remarkable parallelism in emission characteristics between
dwarfs and supergiants of spectral type M. Further investiagtion of
this point seems 1n- dicated. This investigation was supported by the
Office of Naval Research. I.Pub. A.S.P. 53, 244, 1941. 2.K. C. Gordon
and G. E. Kron, Pub. A.S.P. 6i, 210, 1949. 3.Ap. J. 107, 94, 1948. Yale
University Observatory, New Haven, Conn.
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Title: Continuous absorption by interstellar molecules.
Authors: Wildt, Rupert
1949AJ.....54..139W Altcode:
Certain diatomic molecules possibly quite common in interstellar
space deserve attention for their continuous absorption, although
such spectra are not strong enough to affect interstellar absorption,
as the term is understood in relation to the apparent magnitude of
distant stars. However, the photodissociation resulting from such
molecular absorption might be important among the processes by which
the radiant energy of interstellar space is brought into interaction
with the kinetic energy of its gaseous population. The relevance
of continuous molecular absorption to the problem of the kinetic
temperature of interstellar matter was recognized by L. Spitzer,
Jr.1 This note deals mainly with two interesting hydrogen spectra not
mentioned by Spitzer. Both ionized and neutral hydrogen molecules have
continuous absorption spectra between XI 000 and X3000, involving the
following transitions: H2+(Is(rI~5t) hvHH2+(2~cr2~ffi) HII(Is2S) H~ and
H(Is2S) H(Is2S) HH2(Is(r2p~1~0~) hPHH2(IsJ2sJ1~0+). The first spectrum
is the dissociation continuum of the ground state of H2+. The second
spectrum is an association continuum: two colliding hydrogen atoms in
their ground states, provided their electronic spins are parallel,
constitute an unstable molecular state which can be transformed
into a stable excited state by absorption of a suitable photon. Both
spectra are of great intrinsic strength, the f-value summed over all
frequencies being nearly I for H1~ and probably between I and 2 for
H2. Hence H2+ is highly susceptible to decomposition even in the H
I regions of interstellar space, since it is not protected against
photodissociation by the Lyman continuum of atomic hydrogen. Formation
of H2+ occurs by collision between H and H~, followed by emission
of a photon: this is one of the rare cases in which recombination
into the ground state by double collision is permitted under the
electronic transition rules. Recombination of two hydrogen atoms into
the ground state of H2 is feasible only by a triple collision and,
therefore, must be quite exceptional in interstellar space. On the
other hand, H2 in its singlet ground state is well shielded against
photodissociation and photoionization by the Lyman continuum, as Spitzer
pointed out. Because triplet-singlet transitions are forbidden in
such light molecules as H2, the excited triplet molecules originating
from photoassociation must have a very short life-time, decomposing
spontaneously via the lowest (unstable) triplet state. Considered
genetically, the hydrogen molecules of interstellar space fall into
two classes, vlz. singlet molecules, which may be rare, but should be
stable, and triplet molecules, which should be common ~n H I regions,
though rather short- lived. The optimum rate of formation of H2+ is
obtained if protons and hydrogen atoms are present in amounts of the
same order of magnitude. Hence the existence of H2~ is practically
restricted to the narrow transition zones between the H II and H I
regions of interstellar space, and consequently the formation and decay
of H2+ should not be of great importance in evaluating the kinetic
temperature of the bulk of interstellar matter. Further discussion
of the H2+-effect must await completion of the work on the c4ntinuous
absorption coefficient of this molecule, ~vhich is now being undertaken
by Prof. Massey and Dr. Buckingham. Transition probabilities and mean
life-times for the four lowest vibrational states of the I~g+ level of
H2 have been derived by A. S. Coolidge, H. James and R. D. Present.2
A naive application of the Franck-Condon principle would lead to the
expectation that a marked transfer of energy from the interstellar
radiation field (by the association continuum) to the kinetic energy
of the hydrogen gas (by the spontaneous dissociation of the excited
triplet molecules) could take place, because absorption of photons
would occur on the average at greater nuclear distances (consuming
photons of higher frequencies) than re-emission (generating photons
of lower frequencies). But the rigorous analysis of Coolidge, James
and Present indicates that re-emission from the excited vibrational
states occurs predominantly from the outer part of the potential curve,
thus producing again high-frequency radiation and low kinetic energy
of the receding atoms. Loss and gain of the kinetic energy of the
atomic hydrogen appear largely to cancel, and qualitatively one must
conclude that the transitory existence of the triplet molecules does
not appreciably raise the kinetic temperature of the hydrogen gas. A
quantitative test of this surmise would demand laborious numerical
integrations for various sets of assumed kinetic temperatures and
energy curves of interstellar radiation. It would also be necessary
to extend the work of Coolidge, James and Present to the transition
probabilities for the higher vibrational states, which are reached
by absorption of interstellar radiation of wave lengths shorter than
2000. Another hypothetical constituent of the H II regions are HeH+
molecules, which could be formed by collisions between protons and
unexcited helium atoms. According to quantum mechanical computations
these molecules have a stable ground state with a dissociation energy
of I. I volt,3 and in fact they have frequently been observed in the
mass spectrograph. By capture of an electron HeH+ would dissociate,
as the ground state of the neutral helium hydride is unstable. No
spectrum of HeH+ has so far been observed in the laboratory, and little
is known about the theoretical energy level diagram. I.A~. J. 107, 6,
1948. 2.Phys. Rev. 55, 184, 1939. 3.S. Toh, Proc. Phys. Math. Soc. Japan
22, 119, 1940. Yale University Observatory,s1;0;537]New Haven, Conn.
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Title: On the Absorption Continuum of the Negative Oxygen Ion
Authors: Wildt, Rupert; Chandrasekhar, S.
1947PMcCO...9..145W Altcode:
No abstract at ADS
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Title: The Constitution of the planets (Council Report on the progress
of astronomy)
Authors: Wildt, R.
1947MNRAS.107...84W Altcode:
No abstract at ADS
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Title: An Interpretation of the Heights of Lines in the Solar
Chromosphere.
Authors: Wildt, Rupert
1947ApJ...105...36W Altcode:
General theory-The heights of different emission lines in the
chromosphere, estimated from slitless flash spectrograms taken on a
stationaryplate, depend on the total number of emitting atoms contained
in a column along the line of sight, on the threshold sensitivity of
the photographic emulsion, and on the transparency of the earth's
atmosphere and of the optical system. Theoretical intensitis of a
group of related lines originating from the same element are plotted
against the estimated heights, H, and this plot is represented by a
continuous function, E(H). The transformation of E(H) into the spatial
density of the emitting atoms would be a straight problem of geometry
if it were not for the interference of two physical effects introduced
by the process of observation. First, the extra-terrestrial surface
brightness of the chromosphere is distorted by atmospheric scintilla-
tion,which produces a tremor disk around every surface element of the
chromosophere as it appears in pro- jection. Second, since during the
photographic exposure the moon covers, or uncovers, part of the lower
chromosphere, the light emitted at different levels is recorded with
different exposure times; and, for lack of optical resolving-power,
the chromospheric crescents portrayed on a flash spectrogram are
an aggregate of superimposed images taken with varying exposure
times. The correction of the observed function E(H), obtained with
a finite exposure time, to an infinitesimally short exposure, as it
were, requires the solution of a certain integral equation, which
can be effected simply by refrated differentia- tion. The resulting
function,f(H), can then be freed from the distortion by scintillation,
which proves to be numerically insignificant. This procedure has been
applied to the comprehensive list of heights of flash lines estimated
by S. A. MitcJiell. Density gradients-The radial decay of the density of
hydrogen in the chromosphere is strictly expo- nential up to heights of
the order of 15,000 km, numerically proportional to exp (-0.92 X 10-8
cm' H); the density gradients derived from the Balmer and the Paschen
series are in good agreement. The same density gradient of hydrogen
results from a comparison of the electron density at the base of the
çhromo- sphere with that at the elevation of 15,000 km, deduced by
Baumbach from the absolute intensity of the continuous spectrum of the
solar corona, because the free electrons are nearly all produced by
the ionization of hydrogen, by far the most abundant element in the
solar atmosphere. The density laws of the metals can be represented
as a sum of two or three exponentials. At heights less than 2000 km,
their gradients are much steeper than that of hydrogen: but between
3000 and 6000 km they seem to approach the hydrogen gradient. The
density gradients of Fe i and Fe ii are compatible with the existence
of ionization equilibrium with constant temperature throughout the
chromosphere. Excitation temperatures for Fe i and Ti ii are of
the order of 30000_40000 K and increase with increasing excitation
potentials. The density gradient of He i between 2000 and 6000 km is
about one-quarter of that of hydrogen; the observations do not yield any
confirmation of the density maximum of He i below the 2000 km claimed by
other investigators. A bsolute densities.-On the Teller-Inglis theory,
the quantum number (n = 40) of the last resolved member of the Paschen
series implies an electron pressure of 0.11 dynes/cm-2 at the level H =
500 km. From this figure the partial pressure of hydrogen can be found
if the abundance ratio, A, of hydrogen to all the electron-producing
metals is known. Relative abundances of Na, Mg, Al, Ca, Fe, Cu,
and Sr in the chromosphere are derived from the estimated heights
and from absolute transition probabilities; these ratios agree quite
well with those found by Russell from the Fraunhofer spectrum. While
the chromosphere appears to be well mixed as regards the metals, the
abundance ratio, A, of hydrogen to the sum of the metals increases
greatly with height. This variation of A is evaluated by a comparison
of lines of Fe i and the Balmer series; and the extrapolated value of
A at the base of the chromosphere agrees as to order of magnitude with
that re- sulting from B. Stromgren's model of the solar photosphere. The
numbers of atoms per cubic centimeter at the level H = 500 km are: log
CH = + 15.63 for neutral hydrogen, and log CFe = +9.53 for neutral iron
---------------------------------------------------------
Title: An Interpretation of the Heights of Lines in the Solar
Chromosphere
Authors: Wildt, Rupert
1947PMcCO...9..249W Altcode:
No abstract at ADS
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Title: Ultra-violet spectra of R stars
Authors: Wildt, Rupert
1946PAAS...10R.150W Altcode:
No abstract at ADS
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Title: Theoretical color temperatures of hydrogen atmospheres
Authors: Wildt, Rupert
1946PAAS...10S..71W Altcode:
No abstract at ADS
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Title: On the Absorption Continuum of the Negative Oxygen Ion.
Authors: Wildt, Rupert; Chandrasekhar, S.
1944ApJ...100...87W Altcode:
A new determination of the electron affinity of oxygen (3.07
e.v.) suggests that the ionization contin- uum of 0 in the photographic
ultraviolet region becomes so strong in late K and M stars that its
con- tribution to the monochromatic absorption coefficient cannot be
neglected. The influence of 0 on the Rosseland mean is insignificant. A
discontinuity in the spectra of M giants, first observed by Lindblad,
is tentatively identified with the absorption edge of 0-near X 4050. The
theoretical strength of the Lind- blad discontinuity depends on the
abundance ratio of atomic oxygen to atomic hydrogen, which in M stars
varies with the pressure-sensitive shift of the dissociation equilibrium
of the several hydrides and oxides. The result is a positive absolute
magnitude effect for the Lindblad discontinuity. The differential
of free-oxygen abundance implied by Lindblad's spectrophotometric
observations agrees as to order of magnitude with that predicted by
Russell from the dissociation equilibrium in giant and dwarf stars of
the oxygen branch
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Title: On the Chemistry of the Atmosphere of Venus.
Authors: Wildt, Rupert
1942ApJ....96..312W Altcode:
Unpublished data by J. F. Walker show that the clouds of Venus cannot
be composed of solid poiy- oxymethylene hydrates. Since the clouds
cannot consist of water, it is suggested that a small deficiency in the
aqueous component of the primordial magma of Venus may have prevented
the formation of a hydro- sphere; i.e., all water may have been bound
in hydrated minerals
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Title: The theory of continuous stellar spectra
Authors: Wildt, R.
1942Obs....64..195W Altcode:
No abstract at ADS
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Title: The Geochemistry of the Atmosphere and the Constitution of
the Terrestrial Planets
Authors: Wildt, R.
1942RvMP...14..151W Altcode:
No abstract at ADS
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Title: The Absorption Coefficient of the Free-Free Transitions of
the Negative Hydrogen Ion.
Authors: Wheeler, John A.; Wildt, Rupert
1942ApJ....95..281W Altcode:
The absorption coefficients pertaining to the free-free transitions of
H are evaluated throughout the visual range and the entire infrared,
on the basis of an approximate calculation, and are utilized for
the determination of the Rosseland mean of the mass absorption
coefficient of H (sum of free-free and bound-free transitions) in the
low-temperature range (o.8 < 5o4o/T < 2.0). These data set a
lower limit to the opacity of late-type stellar atmospheres, pending
the discovery of further absorption mechanisms likely to become relevant
in the low-temperature range
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Title: The Resonance Bands of the NH Molecule in Spectra of Class R.
Authors: Wildt, Rupert
1941ApJ....93..502W Altcode:
The ultraviolet resonance bands of NH have been identified in the
spectra of R-type stars, photo- graphed at the McDonald Observatory with
dispersions of 120 A/mm and 6o A/mm. The intensities of these bands
have been compared with those of C2, CN, and CH. The large scattering
of these intensities suggests considerable differences in the relative
abundances of H, C, and N
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Title: The Continuous Spectrum of Stellar Atmospheres Consisting
Only of Atoms and Negative Ions of Hydrogen.
Authors: Wildt, Rupert
1941ApJ....93...47W Altcode:
Theoretical color temperatures have been derived for stellar atmospheres
consisting only of H and H in ionization equffibrium, over the range of
effective temperatures 5o4o/T~ = 0.5-1.2 and for differ- ent electron
pressures. Choosing the electron pressure so as to reproduce the value
of the Ba]mer dis- continuity observed by Barbier and Chalonge, the
color temperatures of the spectral types Ao-Fo determined by the same
authors can be tolerably well represented by the H-H mixture. For
the later spectral types the theoretical color temperatures fall
considerably below the corresponding effective temperatures, while the
observed color temperatures are distinctly higher than the effective
ones. It does not seem possible to remove this discrepancy by adding
the conventional metaffic absorption to that of H and H
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Title: On the Possible Existence of Formaldehyde in the Atmosphere
of Venus.
Authors: Wildt, Rupert
1940ApJ....92..247W Altcode:
Ultraviolet spectrograms of Venus, and of the moon for comparison,
were obtained with the long-focus quartz spectrograph (dispersion 21.7
A/mm at A 3300) attached to the 82-inch reflector of the McDonald
Observatory, in order to search for the electronic absorption
spectrum of formaldehyde gas, which might be formed in Venus'
atmosphere by photochemical synthesis. The spectrograms revealed no
sign of absorption by CH2O, while a mass of this gas equivalent to 3
mm-atm, under standard conditions, should have been sufficient for
spectroscopic identification. This negative result does not refute
the assumption that the photochemical formation of CH2O has played an
important role in Venus' atmosphere during the past. In the light of
Tarnmann's theory of the origin of the terrestrial oxygen, the lack
of oxygen on Venus indicates that the primordial atmos- phere of this
planet must have been extremely poor in water vapor. A tenuous atmos-
phere of water vapor and carbon dioxide affords the very conditions
for the photochemi- cal synthesis of formaldehyde, which appears to
be capable of proceeding until the sup- ply of either of these gases
has been exhausted. In a moist atmosphere CH2O rapidily polymerizes
into a mixture of polyoxymethylene hydrates, (CH2O)~ H20, a white
crystaffine solid. From laboratory data it is concluded that the amount
of gaseous CH2O existing in equilibrium with the solid polymers is
exceedingly small, which would seem to account for the failure of the
spectroscopic test. The vapor tension of the solid polymers in the
presumable range of Venus' atmospheric temperature is high enough
to permit the dissolution and formation of clouds by processes of
sublimation and sub- sequent condensation. As Venus' atmosphere is now
spectroscopically free from water vapor but is obviously filled with
clouds, the nature of which has never been settled, it is tentatively
suggested that solid polyoxymethylene hydrates constitute the clouds
shrouding the planet's surface
---------------------------------------------------------
Title: Note on the Surface Temperature of Venus.
Authors: Wildt, Rupert
1940ApJ....91..266W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Negative Ions of Hydrogen and the Opacity of Stellar
Atmospheres.
Authors: Wildt, Rupert
1939ApJ....90..611W Altcode:
Compared to the current theory of the atmospheric absorption
coefficient, the photo- spheric level is raised considerably in all
spectral types later than F5 by including the contribution to the
opacity made by the negative ions of hydrogen. Likewise, the dis-
continuity at the Balmer limit is greatly reduced, so the values of
this quantity ob- served in F stars can be represented without the
assumption, advocated by Unsold, of an abundance ratio of hydrogen
to metals equal to 50: I. The abundance ratio adopted by Russell and
Pamiekoek (H : M = boo: i) appears to be compatible with the observa-
tions of the Balmer discontinuity
---------------------------------------------------------
Title: On the chemical nature of the colouration of Jupiter's
cloud forms
Authors: Wildt, Rupert
1939MNRAS..99..616W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Electron Affinity in Astrophysics.
Authors: Wildt, Rupert
1939ApJ....89..295W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Contribution to the opacity of stellar atmospheres by negative
hydrogen ions
Authors: Wildt, Rupert
1939PAAS....9R.236W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On the state of matter in the interior of the planets
Authors: Wildt, Rupert
1939PAAS....9Q.138W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On the State of Matter in the Interior of the Planets
Authors: Wildt, Rupert
1938ApJ....87..508W Altcode:
The bulk of mass in the interior of the planets is in the ordinary
condensed state. Only in the central parts of Jupiter and Saturn may
there be matter in a state approach- ing the degenerate one. This is
concluded from the central pressures of the terrestrial planets, as
evaluated by Jeifreys, and from the internal pressures of the giant
planets, which are computed here for a model consisting of a core
similar in structure to the terrestrial planets, covered by a layer
of ice and a layer of solid hydrogen on top of it. In this hydrogen
layer the conditions are realized under which hydrogen should change
to a metaffic modification predicted by theory. The condensation of
ice VII from the primeval atmosphere must have started long before the
temperature had dropped to the critical one, and probably was finished
before the critical point was reached, which would imply that there
never was on the giant planets an ocean of a depth comparable to the
total mass of H20 present
---------------------------------------------------------
Title: Photochemistry of Planetary Atmospheres
Authors: Wildt, Rupert
1937ApJ....86..321W Altcode:
All polyatomic molecules detected in planetary atmospheres are
highly sensitive to ultraviolet solar radiation. Their photochemical
decomposition must be followed by secondary chemical reactions,
reuniting the products of dissociation, in order to main- tain the
observed stationary composition of the atmospheres. The stability of
methane and carbon dioxide is reasonably accounted for, but that of
ammonia remains unex- plained at present. The existence of methane and
the failure to detect any other hydro- carbon indicate the presence
of plenty of hydrogen on the giant planets, and most probably there
is no carbon monoxide, carbon dioxide, or hydrogen sulphide at their
surfaces. Small amounts of sundry molecules, not observed so far, are
certain to be formed in consequence of the photochemical processes, and
eventually these compounds may be detected under favorable circumstances
---------------------------------------------------------
Title: Note on stellar ionization and electric fields
Authors: Wildt, Rupert
1937MNRAS..97..225W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Low-Dispersion Spectra of Red Stars
Authors: Wildt, Rupert
1936ApJ....84..303W Altcode:
Over the range from A 3000 to X 9000 (total dispersion 3 mm
approximately) the spectra of selected late-type stars have been
compared. M giants and N stars are marked by a continuous absorption
of wave-lengths shorter than X 4000, the amount being of the order
o~'5 and 2~5, respectively. Types S and gM cannot be distinguished
on low-dispersion spectrograms. Dwarfs of class M have a strong
ultra-violet spectrum and R stars a fairly strong one. Various
absorption bands are found in the far ultra- violet and are attributed
tentatively to CN, CH, NH, OH, CaH. The classes R and N are possibly to
be regarded as forming separate, parallel branches. The hypothetical
physical processes causing the continuous ultra-violet absorption in
gM and N stars are discussed.
---------------------------------------------------------
Title: Equilibrium of Stellar Atmospheres Under a Temperature Gradient
Authors: Wildt, Rupert
1936ApJ....83..202W Altcode:
If the temperature gradient maintained by the radiation flux is smaller
than the adiabatic gradient of the stellar matter and, therefore,
is not sufficient to set up con- vection currents, the constituents
of the atmosphere will be separated partially by diffusion. For all
constituents participating in processes of dissociation or ionization
there are remarkable deviations from the well-known exponential
distribution of the partial pressures (depending only on the molecular
weight), the additional terms con- taming the space derivatives of
the thermodynamical equilibrium constants. The kinetic equivalents
to these terms are stationary diffusion currents, which transport
reaction energy and increase the heat conductivity, although there is
no net flux of mass. This diffusion equilibrium may be realized in the
atmospheres of early B stars and of stars between the types G~ and M,
which ought to be free from convection
---------------------------------------------------------
Title: No. 538. Equilibrium of stellar atmospheres under a temperature
gradient.
Authors: Wildt, Rupert.
1936CMWCI.538....1W Altcode: 1936QB4.M93n538....
No abstract at ADS
---------------------------------------------------------
Title: No. 551. Low-dispersion spectra of red stars.
Authors: Wildt, Rupert.
1936CMWCI.551....1W Altcode: 1936QB4.M93n551....
No abstract at ADS
---------------------------------------------------------
Title: Dissociation and Ionization Equilibria in Stellar Atmospheres
Authors: Wildt, Rupert
1935PASP...47..227W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Atmospheres of the Giant Planets
Authors: Wildt, R.
1934Natur.134..418W Altcode:
IN their article on the atmospheres of the giant planets<SUP>1</SUP>
Drs. A. Adel and V. M. Slipher suggest that a predominantly hydrocarbon
structure might not be at all unlikely for these planets; this
conclusion is also indicated, in their opinion, by the fact that the
mean densities of these celestial bodies are in a class with densities
of most organic liquids.
---------------------------------------------------------
Title: Über die stellare Dissoziation des
Wasserstoffmoleküls. (Veröffentlichungen der
Universitäts-Sternwarte Göttingen, Nr. 42. ) Mit 1 Abbildung.
Authors: Wildt, Rupert
1934ZA......9..176W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Über die stellare Dissoziation des Wasserstoffmolekuls
Authors: Wildt, Rupert
1934VeGoe...3..208W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Über den inneren Aufbau der grossen Planeten
Authors: Wildt, Rupert
1933VeGoe...3..179W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Kondensation in Sternatmosphären
Authors: Wildt, Rupert
1933VeGoe...3...35W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Ozon und Sauerstoff in den Planetenatmosphären
Authors: Wildt, Rupert
1933VeGoe...3..151W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Kondensation in Sternatmosphären. (Veröffentlichungen der
Universitäts- Sternwarte Göttingen Nr. 33.) Mit 1 Abbildung.
Authors: Wildt, Rupert
1933ZA......6..345W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Über das ultrarote Spektrum des Planeten Saturn
Authors: Wildt, Rupert
1932VeGoe...2..216W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Absorptionsspektren und Atmosphären der gros;en Planeten
Authors: Wildt, Rupert
1932VeGoe...2..171W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Das Spektrum des Planeten Jupiter
Authors: Wildt, Rupert; Meyer, E. J.
1931VeGoe...2..141W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Das Spektrum des Planeten Jupiter. Mit 11
Abbildungen. (Eingegangen am 30. September 1931)
Authors: Wildt, R.; Meyer, E. J.
1931ZA......3..354W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Über Eigentümlichkeiten panchromatischer Platten
Authors: Wildt, Rupert
1931VeGoe...2..157W Altcode:
No abstract at ADS
