Metal-poor stars. I - Evolution from the main sequence to the giant branch
Metal-poor stars evolution during hydrogen and helium burning from main sequence to giant branch, estimating relative cluster ages
Iben, I., Jr.↗
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A perturbed red-giant model
Red giant model, investigating inclusion of semirelativistic partially degenerate gas characteristics by perturbationary technique
Edwards, T. W.↗
Analysis of the Hyades giant stars epsilon and gamma Tau
Hyades giant stars epsilon and gamma Tau strong line profile analysis, obtaining effective temperatures
Krishna Swamy, K. S.↗
Atmospheres of metal-deficient stars - Giant stars
Main sequence and giant stars atmospheric structure models, noting metal deficiency effects
Krishna Swamy, K. S.↗
Stellar evolution from main sequence to red giant
Metal-rich star evolution from main sequence to red giant, examining mass, nuclear reactions and theoretical models
Iben, I., Jr.↗
Lithium and the s-process in red-giant stars
Red giant star s-process and subsequent delayed electron capture, accounting for large Li abundances
Cameron, A. G. W.↗
A model-atmosphere analysis of five apparently super-metal-rich K giants
Super metal rich K giant stars atmospheric model, obtaining abundances and turbulent velocity parameter
Carbon, D. F.↗
A new method for the determination of the mixing ratio hydrogen to helium in the giant planets.
By using a numerical iterative method, it is demonstrated that the mixing ratio H2/He on the giant planets can be inferred from spectral measurements of the intensity emitted by these planets in the far infrared range. The method is successfully applied to synthetic spectra of Saturn computed from atmospheric thermal models. The effect of random and systematic measurement errors on the determination of the mixing ratio is also studied.
Gautier, D.↗
Luminosity functions for K giant stars derived from the two-micron sky survey.
Description of a method for determining either the space density or the luminosity function from star counts covering large areas of sky. Space density is assumed to vary only in the direction perpendicular to the galactic plane. The method extends that derived for use with the star counts in the Selected Areas by allowing for an integration over a wide and continuous range of galactic latitudes, and is therefore applicable to surveys where the number of stars per square degree is small but the area surveyed is an appreciable fraction of the sky. The catalog (IRC) produced from the 2-micron sky survey at Caltech is such a survey. Application of the method to a selection of IRC stars dominated by K giants shows that if these stars obey Oort's determination of their normalized space density perpendicular to the galactic plane than the dispersion of their 2.2-micron luminosity distribution must be large - i.e., on the order of plus or minus 1.0 min within a single spectral subtype. This result is in accord with conclusions recently set forth by Jung (1970).
Hughes, E. E., Jr.↗
Metal-poor stars. IV - The evolution of red giants.
Detailed evolutionary calculations for six Population-II red giants are presented. The first five of these models are followed from the zero age main sequence to the onset of the helium flash. The sixth model allows the effect of direct electron-neutrino interactions to be estimated. The updated input physics and evolutionary code are described briefly. The results of the calculations are presented in a manner pertinent to later stages of evolutions and suitable for comparison with observations.
Rood, R. T.↗
Effect of a giant impact on the thermal evolution of the moon
The effects of a giant impact on the thermal evolution of the moon are investigated. It is found that an impact similar to that of Imbrium creates lateral temperature variations of more than 200 deg within the upper 200 km of the moon. Starting with a common lithosphere of 70 km thickness, the lithosphere beneath the basin grows to 200 km in thickness within 0.5 b.y. after the impact, while that beneath the highlands reaches to only 100 km in thickness during this period. The model presented for the thermal evolution of the moon is compatible with (1) the existence of mascons for more than 3 b.y., (2) the late magmatization and subsequent volcanic activities during 4 to 3 b.y. ago, and (3) the negative gravity rings around the large mascons.
Arkani-Hamed, J.↗
Models of the giant planets
Models of the giant planets were constructed based on the assumption that the hydrogen to helium ratio is solar in these planets. This assumption, together with arguments about the condensation sequence in the primitive solar nebula, yields models with a central core of rock and possibly ice surrounded by an envelope of hydrogen, helium, methane, ammonia, and water. These last three volatiles many be individually enhanced due to condensation at the period of core formation. Jupiter was found to have a core of about 40 earth masses and a water enhancement in the atmosphere of about 7.5 times the solar value. Saturn was found to have a core of 20 earth masses and a water enhancement in the atmosphere of about 25 times the solar value. Rock plus ice constitute 75-85% of the mass of Uranus and Neptune.
Podolak, M.↗
Air pollution from future giant jetports
Because aircraft arrive and depart in a generally upwind direction, the pollutants are deposited in a narrow corridor extending downwind of the airport. Vertical mixing in the turbulent atmosphere will not dilute such a trail, since the pollutants are distributed vertically during the landing and take-off operations. As a consequence, airport pollution may persist twenty to forty miles downwind without much attenuation. Based on this simple meteorological model, calculations of the ambient levels of nitric oxide and particulates to be expected downwind of a giant jetport show them to be about equal to those in present urban environments. These calculations are based on measured emission rates from jet engines and estimates of aircraft performance and traffic for future jetports.
Fay, J. A.↗
Physical properties of giant planets
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.
Wildt, R.↗
Tides in the giant planets
Goldreich and Soter's (1966) discussion of tidal dissipation in the Jovian planets is reexamined for planetary models which possess an appreciable internal heat source. The tidal torque produced in a fully liquid planet is calculated as a function of the average viscosity in the interior. Turbulent viscosity, which is produced by the convection of internal heat to the surface, seems to be capable of producing small (about a few per cent) changes in the orbits of the innermost satellites of Jupiter over the age of the solar system. The basic regularity of many of the giant planet satellite systems is probably due to other, perhaps primordial, causes.
Hubbard, W. B.↗
Mass loss in red giants and supergiants
The circumstellar envelopes surrounding 13 late-type giants and supergiants have been studied using a homogeneous collection of high-resolution, photoelectric scans of strong optical resonance lines. Various properties of the envelopes, including the mass loss rate, dilution factor, hydrogen density, and degree of ionization, have been determined quantitatively.
Sanner, F.↗
Evolutionary problems of Cepheids and other giants investigated with new radiative opacities
Comparison of evolutionary tracks, pulsation constants, and linearized pulsational-stability coefficients for stellar models applicable to the problems of classical Cepheids, whose structures were calculated using the Cox-Stewart (1965) opacities and a recently computed set of opacities. The latter are based on the hot 'Thomas-Fermi' statistical model of the atom for all elements heavier than hydrogen and helium; they contain larger helium and metals contributions, but a smaller hydrogen contribution than the former ones for the same chemical composition. The difference in metals contribution affects mainly the location and shape of the evolutionary tracks on the H-R diagram, while the difference in hydrogen and helium contributions has its greatest effect on the pulsational properties of the Cepheid models. From the comparison of evolutionary tracks it is concluded that: (1) the theoretical M/L relation for evolved giants is changed very little by using the second set of opacities; (2) Q-values for the fundamental mode of radial pulsation in Cepheid envelope models increase if the second set is used, but the classical mass discrepancy remains; and (3) the second set leads to pulsational-instability.
Carson, T. R.↗
Late-type giants and supergiants in the galactic center
An absorption feature at 2.3 microns attributed to CO molecules in stellar atmospheres has been found in some, but not all, of the infrared sources within 20 arcsec of the galactic center. The absorption is characteristic of that found in M-type giant and supergiant stars. The infrared source coincident with the sub-arcsecond nonthermal radio source does not show CO absorption.
Neugebauer, G.↗