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in subjects: "Star Evolution"  
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Induced star formation and morphological evolution in very high redshift radio galaxies

Description: Near-infrared, sub-arcsecond seeing images obtained with the W M Keck I Telescope of show strong evolution at rest-frame optical wavelengths in the morphologies of high redshift radio galaxies (HzRGs) with 1 9 < z < 4 4 The structures change from large-scale low surface brightness regions surrounding bright, multiple component and often radio-aligned features at z > 3, to much more compact and symmetrical shapes at z < 3 The linear sizes ({approximately} 10 kpc) and luminosities (M{sub B} {appr… more
Date: October 1, 1997
Creator: van Breugel, W. J. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Pulsations and outbursts of luminous blue variables

Description: We propose an outburst mechanism for the most luminous stars in our and other galaxies. These million solar luminosity stars, with masses (after earlier mass loss) of between 20 and maybe 70 solar masses, are pulsationally unstable for both radial and low-degree nonradial modes. Some of these modes are ``strange,`` meaning mostly that the pulsations are concentrated near the stellar surface and have very rapid growth rates in linear theory. The pulsation driving is by both the high iron line op… more
Date: June 1, 1997
Creator: Cox, Arthur N.; Guzik, Joyce A.; Soukup, Michael S. & Despain, Kate M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Helium-induced reactions in astrophysics

Description: Helium-induced reactions play a crucial role in stellar nucleosynthesis. Carbon and oxygen are produced mainly during the helium-burning phase by the chain of reactions {sup 8}Be({alpha}, {gamma} + e{sup +}e{sup {minus}}){sup 12}C({alpha}, {gamma}){sup 16}O. The first step, often called triple-{alpha} capture, was proposed by Hoyle to bypass the mass stability gap at {sup 8}Be. The second step gives rise to the largest uncertainty in most of the calculated stellar abundances. Later {alpha}-capt… more
Date: November 1, 1997
Creator: Hale, G.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Neutron star evolution and emission

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors investigated the evolution and radiation characteristics of individual neutron stars and stellar systems. The work concentrated on phenomena where new techniques and observations are dramatically enlarging the understanding of stellar phenomena. Part of this project was a study of x-ray and gamma-ray emission from neutron stars and other… more
Date: August 1, 1997
Creator: Epstein, R. I.; Edwards, B. C. & Haines, T. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Bulge Delta Scuti Stars in the MACHO database

Description: The authors describe the search for {delta} Scuti stars in the MACHO database of bulge fields. Concentrating on a sample of high amplitude {delta} Scutis, they examine the light curves and pulsation modes. They also discuss their spatial distribution and evolutionary status using mean colors and absolute magnitudes.
Date: July 29, 1997
Creator: Minnniti, D.; Alcock, C.; Alves, D. R.; Axelrod, T. S.; Becker, A.; Bennett, D. P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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