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NASA NTRS1974

Oparin and the origin of life - Cosmological considerations

The question of the origin of life is examined on a cosmological scale from early observations made by Oparin. Even by a comparison of the amount of data presently available from telescopic and spacecraft observations Oparin's conclusions have been confirmed. The concept of panspermia is rejected and details of the role of carbon on earth are presented. Formation of C2, CN and CH is explained and various aspects of the atmospheres of planets are considered. Finally, the origin of amides, amines and other nitrogenous derivatives from hydrocarbons is discussed.

Young, R. S.↗
NASA NTRS1975

Absolute spectrophotometry in M31 and M32

For a number of places in the bulge of M31, and for two places in M32, photometric scans from lambda = 3300 A to lambda = 10,600 A have been obtained with the multichannel spectrometer on the 5-m Hale telescope. The scans show that in both objects the color temperature (particularly shortward of 5000 A) decreases toward the center, and that the strength of the CN bands increases toward the center in both objects, in agreement with other earlier observations. The new data can all be interpreted in terms of an increase of heavy-element abundance toward the center in both objects by a factor probably less than 2, and by an excess of heavy elements in M31 compared with M32 by a factor probably greater than 2, in qualitative agreement with earlier conclusions of other observers.

Oke, J. B.↗
NASA NTRS1975

Interstellar K I and Na I absorption lines near rho Ophiuchi

Results are reported for photoelectric interferometric scans of the interstellar K I (7699 A) and Na I D1 absorption lines toward rho Oph AB and omicron Sco in the complex of dark clouds near rho Oph. The scans are found to reveal a well-marked line multiplicity toward both stars. It is shown that the resolved components of the line profiles can provide a natural explanation for the difference between the radial velocity of the strongest atomic lines of Na I and Ca II and that of the much weaker molecular lines of CH(+), CH, and CN that was previously observed toward rho Oph. The less saturated 7699-A lines toward both stars yield K I column densities roughly consistent with the calculated interstellar reddening.

Hobbs, L. M.↗
NASA NTRS1976

Photometry of the cometary atmosphere: A review

Photometry and polarimetry of the cometary heads one of the most important sources of information about the physical processes in comets is reviewed. Methods of inspection discussed include: narrow band photometry, wide band photometry, color photography, tilting filter techniques, and photoelectric spectrum scanning. Results of photoelectric observations of comets are described including photoelectric and infrared measurements of comet Kohoutek. Photometric profiles of the coma in monochromatic light are used to determine the lifetime of the parent molecules for the observed radicals, CN and C2.

Vanysek, V.↗
NASA NTRS1976

H2O(+) ions in comets: Comet Kohoutek (1973f) and comet Bradfield (1974b)

The image tube Cassegrain slit spectra of comet Kohoutek and Bradfield calibrated and reduced to relative intensities are discussed. Monochromatic changes in the surface brightness for various neutral and ionized molecules are determined. The intensities of C2 and CN decreased approximately four times faster than the intensity change for the H2O(+) features. It is shown that the excitation mechanism for the observed H2O(+) bands is by fluorescent scattering of the incident solar radiation. The effects of solar activity on the photoionization rate of H2O in a comet are discussed. Observations of another bright comet at the time of maximum solar activity are needed to determine changes in band intensities of comet tail ions due to solar activity.

Wehinger, P.↗
NASA NTRS1976

Spectrophotometry of comet Kohoutek (1973f) during pre-perihelion period

Scans of the head of comet Kohoutek obtained during the pre-perihelion period with a photoelectric spectrum scanner are discussed. The mean relative flux distributions and the continuum energy distribution of the head of comet Kohoutek are given and normalized to 479 nm. The emission features of CN, C3, Ch, and the principal Swan band sequences of C2 and Na are identified and discussed. The adopted monochromatic values relative to 479 nm are given and plotted along with the energy distribution of the sun.

Babu, G. S. D.↗
NASA NTRS1976

Silicon materials task of the low cost solar array project, part 2

Purity requirements for solar cell grade silicon material was developed and defined by evaluating the effects of specific impurities and impurity levels on the performance of silicon solar cells. Also, data was generated forming the basis for cost-tradeoff analyses of silicon solar cell material. Growth, evaluation, solar cell fabrication and testing was completed for the baseline boron-doped Czochralski material. Measurements indicate Cn and Mn seriously degrade cell performance, while neither Ni nor Cu produce any serious reduction in cell efficiency.

Hopkins, R. H.↗
NASA NTRS1976

Monochromatic observations of Comet Tago-Sato-Kosaka 1969g /1969IX/

Isophotes have been determined from 10 narrow-band filter photographs of Comet Tago-Sato-Kosaka 1969g (1969IX) taken between Feb. 11 and 14, 1970. The five interference filters used were centered on the CN band sequence at 3383A, the C2 band sequence at 4737A and 5165A, the C3 sequence at 4050A, and the continuum at 5300A. Gradients of intensity in various directions from the nucleus have been derived from the isophotes.

Rahe, J.↗
NASA NTRS1975

Monochromatic and white-light observations of Comet Bennett 1969i /1970II/

Isophotes have been determined from 32 photographs of Comet Bennett 1969i (1970II) taken during the period from March 28 to April 18, 1970. The six interference filters used were centered on the CN band at 3383A, the C2 band sequences at 4737A and 5165A, the CO(+) band at 4277A, on the sodium D-lines at 5893A, and the continuum at 5300A. Intensity gradients have been derived from these isophotes.

Rahe, J.↗
NASA NTRS1976

The luminosity dependence of the 1.65-micron flux from K and early M stars - Observations and interpretation

A number of late-type stars of various luminosity classes have been observed in three infrared colors to study the luminosity dependence of the '1.65-micron peak' around the minimum of H(-) absorption. An unexpected luminosity dependence (lower peaks) has been found for K and early M supergiants as compared with the giants. Comparisons with model-atmosphere computations, which are in relatively good agreement with the observations, explain the effect as the result of blocking by CO and CN lines in the infrared.

Bell, R. A.↗
NASA NTRS1976

Color gradients in the nuclear region of M31

Spectrophotometric measurements of the nuclear region of M31 under conditions of excellent seeing with M31 near the zenith and using a 3.8-9.9-in. diameter entrance annulus for the bulge along with a 3.6-in. aperture for the nucleus, show that the nuclear region is only slightly redder and shows marginally stronger CN blends than the bulge. The data can be interpreted in terms of an increase in heavy-element abundance toward the center of M31 by a factor substantially less than two.

Thuan, T. X.↗
NASA NTRS1975

Diffusion in mixed solvents - On the viscosity question

Linear plots of reaction rate vs reciprocal of solvent viscosity are generally used as the classifying criteria for diffusion controlled reactions in fluid solutions and to determine reaction mechanisms in mixed hydroxylic solvents like glycerol and water. This paper presents data which shows that the above-mentioned criteria are insufficient in many cases where nonideal mixed solvent systems are used to increase solvent viscosity. Data correlations suggest that the excess functions determine the variation in reaction rate constants. Kinetic parameters are presented for sucrose-water and methanol-water solvent systems for a reaction involving Fe(CN)6 and zinc uroporphyrin.

Carapellucci, P. A.↗
NASA NTRS1977

Carbon and nitrogen abundances in F- and G-type stars

Carbon and nitrogen abundances have been obtained for a sample of 11-F- and G-type dwarfs covering a range in Fe/H abundance ratio from -0.8 to +0.3. Model atmospheres, which included the effects of convection and line blanketing, were used to calculate synthetic spectra of the CH, CN, and NH molecular bands. Effective oscillator strengths for the bands studied were found by matching synthetic spectra calculated from a model solar atmosphere with the observed solar bands. Many of the metal-poor stars, and particularly the high-velocity stars, were found to have substantial nitrogen over-deficiencies, suggesting that N is manufactured mostly in a secondary manner. The carbon-to-iron ratios were similar to the solar ratio, although there may be slight C over-deficiencies in metal-poor stars. However, the variation in C/Fe is not as marked as that found recently by Hearnshaw (1974). A comprehensive discussion of the theoretical errors is given, and some applications to Galactic evolution are noted.

Clegg, R. E. S.↗
NASA NTRS1977

The chemical evolution of molecular clouds

The nonequilibrium chemistry of dense molecular clouds (10,000 to 1 million hydrogen molecules per cu cm) is studied in the framework of a model that includes the latest published chemical data and most of the recent theoretical advances. In this model the only important external source of ionization is assumed to be high-energy cosmic-ray bombardment; standard charge-transfer reactions are taken into account as well as reactions that transfer charge from molecular ions to trace-metal atoms. Schemes are proposed for the synthesis of such species as NCO, HNCO, and CN. The role played by adsorption and condensation of molecules on the surface of dust grains is investigated, and effects on the chemical evolution of a dense molecular cloud are considered which result from varying the total density or the elemental abundances and from assuming negligible or severe condensation of gaseous species on dust grains. It is shown that the chemical-equilibrium time scale is given approximately by the depletion times of oxygen and nitrogen when the condensation efficiency is negligible; that this time scale is probably in the range from 1 to 4 million years, depending on the elemental composition and initial conditions in the cloud; and that this time scale is insensitive to variations in the total density.

Iglesias, E.↗
NASA NTRS1978

The effects of TiO opacity on the atmospheric structure of cool stars

A quantitative investigation is conducted concerning the effect of TiO opacities on the atmospheric temperature structure in late-type stars. Model atmospheres are computed, taking into account opacity-sampling (OS) or straight-mean (SM) opacities for three singlet and three triplet band systems of TiO. Model atmospheres using OS and SM opacities for TiO are compared with models having no TiO, giving attention to the effects of TiO opacities on the temperature structures of various atmospheres and the usefulness of straight-mean TiO opacities in model atmosphere calculations. The results of the model-atmosphere calculations are presented in two graphs. TiO opacities produce a global atmospheric heating which may reach several hundred kelvins. It is shown quantitatively that the TiO molecule is an important source of atmospheric opacity in cool stars of solar composition. The relative importance of TiO opacities to the thermal structure of a stellar atmosphere is influenced in the outer layers by CO and H2O cooling effects and in the deeper layers by CO, CN, and metal line absorption.

Krupp, B. M.↗
NASA NTRS1978

Airborne photometric observations between 1.25 and 3.25 microns of late-type stars

The stars Alpha Aur (G5 III + G0 III), Alpha Boo (K2 IIIp), Alpha Ori (M1-M2 Ia-Ib), Alpha Sco (M1.5 Iab), Mu Gem (M3 III), and Alpha Her (M5 Ib-II) have been observed using interference filters in five photometric bands between 1.25 and 3.25 microns during seven flights with NASA's Lear Jet Infrared Observatory. The filters were designed to measure molecular features, primarily from CN and CO, and continuum fluxes. By calibrating the photometer in the laboratory against a stabilized blackbody source, relative flux curves have been derived. The energy distributions and the strength of molecular features are discussed. The most interesting result obtained is that the fluxes from Mu Gem and Alpha Her in the filter centered at 3.25 microns seem to be depressed by at least some tenths of a magnitude. Tentatively this depression is proposed to be due to the wings of the two vibration-rotation bands (about 2.7 microns) of hot water vapor. Since water vapor is an important opacity source and its abundance is a sensitive C/O indicator, the proposed interpretation makes renewed efforts to detect water bands in early M stars highly desirable.

Nordh, H. L.↗
NASA NTRS1978

On the monochromatic brightness variations of comets

The nonsteady development of the multispecies atmosphere of a long-period comet approaching the sun is modeled, and the associated monochromatic brightness variations are discussed in terms of the varying abundances of the atmospheric species. A simple homogeneous clathrate structure, 85% of which is H2O, provides the representation for the cometary nucleus. Monochromatic brightness variations of the emission bands due to OH, CN and C2 are found to follow the law proposed by Levin (1943) for small heliocentric distance where a quasi-steady approximation is valid. However, the large time-scales of residence for emitting species leads to a breakdown of Levin's law at large heliocentric distances.

Mendis, D. A.↗
NASA NTRS1978

C3 and infrared spectrophotometry of Y Canum Venaticorum

The 1.2- to 5.6-micron spectrum of the carbon star Y CVn is presented and discussed. The observations were made from the Kuiper Airborne Observatory at an altitude of 12.5 km, thereby avoiding most of the absorption due to terrestrial water vapor. Comparison of Y CVn near 5 microns with laboratory spectra provides possible evidence for the presence of the linear triatomic molecule C3. For the first time in a carbon star the clearly formed band heads of the CN red system between 1.2 and 2.3 microns are observed. Corroborative evidence for the presence of the molecules HCN and C2H2 is presented, and the relative contributions of C3, HCN, and C2H2 to the 3.1-micron absorption band are discussed. Spectra of two other carbon stars, TX Psc and S Cep, are presented for comparison.

Goebel, J. H.↗