A Jupiter atmospheric entry mission
Jupiter atmospheric entry probe mission, discussing descent depths, atmospheric pressure and temperature effects, data return techniques and Grand Tour Missions
Carroll, P. C.↗
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Results for “temperature effects”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Solar array technology for lunar surface applications
Solar array technology for lunar surface applications including silicon cells, cadmium sulphide thin films, temperature effects, prototype module and radiation degradation
Boretz, J. E.↗
Long-term tests of copper sulfide-cadmium sulfide thin-film solar cells under simulated orbital conditions
Copper sulfide-cadmium sulfide thin film solar cells under simulated orbital conditions, including thermal cycling, constant illumination and temperature effects
Clarke, D. R.↗
Temperature dependence of the long-wavelength optical phonons in diamond
Temperature effects on long wavelength photon frequency and linewidth in diamond, using Raman scattering techniques
Anastassakis, E.↗
Influence of target temperature on crater morphology and implications on the origin of craters on lunar glass spheres
Lunar glass spheres cratering origin hypothesis from target temperature effects on crater morphology in targets impacted by high velocity Al projectiles
Carter, J. L.↗
Thermoregulatory responses of a hibernator to preoptic and environmental temperatures
Preoptic and environmental temperature effects on hibernator thermoregulatory responses, noting changes in metabolic rates
Heath, J. E.↗
Development of mathematical models of environmental physiology
Selected articles concerned with mathematical or simulation models of human thermoregulation are presented. The articles presented include: (1) development and use of simulation models in medicine, (2) model of cardio-vascular adjustments during exercise, (3) effective temperature scale based on simple model of human physiological regulatory response, (4) behavioral approach to thermoregulatory set point during exercise, and (5) importance of skin temperature in sweat regulation.
Stolwijk, J. A. J.↗
Heat-transfer testing procedures in phase B shuttle studies with emphasis on phase change data improvement
The procedures used in the application of the phase change technique to the phase B shuttle configuration are discussed along with factors which may affect data accuracy. These factors include variation of thermal properties of phase change model material, sensitivity of measured heat transfer coefficients to the assumed value of the adiabatic to total temperature ratio, and wall temperature effects. These sensitivities are illustrated in sample calculations for a shuttle geometry. Factors which may affect the visual clarity and interpretation of phase change data are discussed, and a method of improving photographic data quality through the use of polarized light is presented.
Throckmorton, D. A.↗
Ultraviolet observations of weak-helium stars
Ultraviolet filter photometry aboard OAO-2 has been carried out for the weak helium stars 3 Cen A, 3 Sco, HD 144334, HD 21699, HD 144844, alpha Scl, HR 8535, HR 8770 and HD 144661. The flux distribution is compared with that of B3 to B8 main sequence and giant stars in terms of color-color diagrams. When allowance is made for line blocking shortward of 2800 A that most of the weak helium stars have normal fluxes in good agreement with their ground-based colors. The star alpha Scl is a light and spectrum variable. The strengthening of Ti II and Sr II lines around 2400 A appears to redistribute flux longward of the Balmer discontinuity. The flux distribution indicates an effective temperature about 1500 K higher than previously determined.
Bernacca, P. L.↗
C-4 155 nm line in beta Cephei
The class of early B variable stars known as beta Cephei stars are characterized by short-period radial velocity and light variations. The coolest stars of this group have an effective temperature of about 20,000 K and the hottest, about 28,000 K. These stars are not related to the classical Cepheids whose temperatures are of the order of 6000 K. The amplitude of the radial velocity variation beta Cephei stars is in the tens of kilometers per second and the light variation is less than 0.2 mag, that is, less than 10 percent. The fastest pulsation interval is 3 hr and the slowest is 6 hr. The prototype beta Cephei has a period of 4 hr 34 min. Ultraviolet observations were taken using OAO 2 to investigate the relationship between the visual and the ultraviolet variations.
Fischel, D.↗
Quantitative results of stellar evolution and pulsation theories.
The discrepancy between the masses of Cepheid variables deduced from evolution theory and pulsation theory is examined. The effect of input physics on evolutionary tracks is first discussed; in particular, changes in the opacity are considered. The sensitivity of pulsation masses to opacity changes and to the ascribed values of luminosity and effective temperature are then analyzed. The Cepheid mass discrepancy is discussed in the light of the results already obtained. Other astronomical evidence, including the mass-luminosity relation for main sequence stars, the solar neutrino flux, and cluster ages are also considered in an attempt to determine the most likely source of error in the event that substantial mass loss has not occurred.
Fricke, K.↗
Observations of zeta Puppis.
The visual line spectrum of zeta Puppis (O4f) cannot be matched by theoretical line profiles computed by Auer and Mihalas (1971) from their non-LTE models. The discrepancy between observation and prediction suggests that deviations from plane-parallel geometry and hydrostatic equilibrium must be accounted for in order for models to represent the atmospheric regions forming the observed lines. Relaxation of these classical assumptions may affect the value of effective temperature for this star derived from observations of its continuous spectrum.
Heap, S. R.↗
The effects of recent opacity corrections on a main-sequence stellar model of 2.25 solar masses.
Comparison of models calculated with the opacities of Carson et al. (1968) and the electron-scattering corrections of Watson with models based on the opacities of Cox et al. (1965). The models have a mass of 2.25 solar masses and a chemical composition with X = 0.596 and Z = 0.02. With the adopted formulas representing the new opacities, it is found that the percentage changes with respect to the model based on the opacities of Cox et al. can be as large as +11 for the stellar radius, -42 for the luminosity, -15 for the effective temperature, -30 for the mass of the convective core, -8 for the central pressure, and -4 for both the central density and the central temperature.
Novotny, E.↗
Backscatter of solar resonance radiation. I.
Calculation of the angular dependence of the intensity of solar Lyman alpha resonantly scattered from neutral interstellar hydrogen which has penetrated the solar system. A simple model which essentially neglects temperature effects, but which includes gravity, radiation pressure, photoionization and charge exchange is used for this calculation. The results are then compared with the observations. The resonant scattering of He I 584 A is also treated.
Johnson, H. E.↗
Reflectance of aqueous solutions
The optical properties and optical constants of water and aqueous solutions were studied to develop an accurate tabulation of graphical representations of the optical constants through a broad spectrum. Manuscripts of articles are presented concerning extinction coefficients, relative specular reflectance, and temperature effect on the water spectrum. Graphs of absolute reflectance, phase shifts, index of refraction, and extinction coefficients for water, heavy water and aqueous solutions are included.
Querry, M. R.↗
Stellar evolution of high mass based on the Ledoux criterion for convection
Theoretical evolutionary sequences of models for stars of 15 and 30 solar masses were computed from the zero-age main sequence to the end of core helium burning. During the earliest stages of core helium depletion, the envelope rapidly expands into the red-supergiant configuration. At 15 solar mass, a blue loop on the H-R diagram ensues if the initial metals abundance, initial helium abundance, or C-12 + alpha particle reaction rate is sufficiently large, or if the 3-alpha reaction rate is sufficiently small. These quantities affect the opacity of the base of the outer convection zone, the mass of the core, and the thermal properties of the core. The blue loop occurs abruptly and fully developed when the critical value of any of these quantities is exceeded, and the effective temperature range and fraction of the lifetime of core helium burning during the slow phase of the blue loop vary surprisingly little. At 30 solar mass no blue loop occurs for any reasonable set of input parameters.
Stothers, R.↗
The last Balmer line and H gamma in model B stars
Profiles of the last few Balmer lines (H12-H27) and the full profiles of the H gamma line were computed for a grid of hydrogen line blanketed model atmospheres. The use of the last hydrogen line and the equivalent width of H gamma provide a quick means of estimating the effective temperature and surface gravity of B stars. Regression curves relating the quantum number of the last hydrogen line to the electron density in the model atmosphere are given. Futhermore, it is shown that the difference in the gravity determination deduced from H gamma equivalent widths using the Edmonds-Schuter-Wells formalism and the Griem wing formulae is, at worst, 0.18 in the common logarithm.
Fischel, D.↗
Abundances in late-type giants.
The narrow-band photometry of Spinrad and Taylor (1969) is analyzed by the synthetic spectra technique. Surface gravities, Doppler broadening velocities, effective temperatures, and metal abundances are determined for 131 K giants. Evolutionary tracks and gravities determined from the photometry are used to give space positions, space velocities, and absolute magnitudes of the 131 stars. We conclude that a class of stars exists with metals and/or nitrogen significantly enhanced with respect to the sun; further that these stars have average space motions similar to those of moderately old Population I stars. The Doppler broadening velocity is found to be a strong function of temperature for K giants, and in some cases, possibly a function of surface gravity.
Gottlieb, D. M.↗