Zobrazeno 91 - 100
of 294
pro vyhledávání: '"Metcalfe, T. S."'
Publikováno v:
Astrophys.J. 602 (2004) L109-L112
We demonstrate that plasmon neutrinos are the dominant form of energy loss in model white dwarf stars down to T_eff ~ 25,000 K, depending on the stellar mass. The lower end of this range overlaps the observed temperatures for the V777 Her star (DBV)
Externí odkaz:
http://arxiv.org/abs/astro-ph/0312303
Publikováno v:
Mon.Not.Roy.Astron.Soc. 344 (2003) L88
We investigate the global pulsation properties of DBV white dwarf models that include both the double-layered envelope structure expected from time-dependent diffusion calculations, as well as a non-uniform C/O core expected from prior nuclear burnin
Externí odkaz:
http://arxiv.org/abs/astro-ph/0306070
Publikováno v:
Mon.Not.Roy.Astron.Soc. 344 (2003) 657
We demonstrate that there is an inherent symmetry in the way high-overtone stellar pulsations sample the core and the envelope, which can potentially lead to an ambiguity in the asteroseismologically derived locations of internal structures. We provi
Externí odkaz:
http://arxiv.org/abs/astro-ph/0305601
Autor:
Metcalfe, T. S., Charbonneau, P.
Publikováno v:
J.Comput.Phys. 185 (2003) 176-193
Genetic algorithms are a class of heuristic search techniques that apply basic evolutionary operators in a computational setting. We have designed a fully parallel and distributed hardware/software implementation of the generalized optimization subro
Externí odkaz:
http://arxiv.org/abs/astro-ph/0208315
The ^12C(alpha,gamma)^16O Nuclear Reaction Rate from Asteroseismology of the DBV White Dwarf CBS 114
Autor:
Metcalfe, T. S., Handler, G.
We have identified seven independent pulsation modes in the helium-atmosphere variable (DBV) white dwarf star CBS 114, based on 65 hours of time-resolved CCD photometry from the 0.75-m telescope at SAAO. We interpret these pulsations as non-radial g-
Externí odkaz:
http://arxiv.org/abs/astro-ph/0208225
Publikováno v:
Mon.Not.Roy.Astron.Soc. 335 (2002) 698
We have acquired 65 h of single-site time-resolved CCD photometry of the pulsating DB white dwarf star CBS 114 and 62 h of two-site high-speed CCD photometry of another DBV, PG 1456+103. The pulsation spectrum of PG 1456+103 is complicated and variab
Externí odkaz:
http://arxiv.org/abs/astro-ph/0205459
Publikováno v:
Astrophys.J. 573 (2002) 803
During helium burning in the core of a red giant, the relative rates of the 3&alpha and ^{12}C(&alpha,&gamma)^{16}O reactions largely determine the final ratio of carbon to oxygen in the resulting white dwarf star. The uncertainty in the 3&alpha reac
Externí odkaz:
http://arxiv.org/abs/astro-ph/0203347
Publikováno v:
2002, ASP Conf. Series v.259, p.602
For many years, astronomers have promised that the study of pulsating white dwarfs would ultimately lead to useful information about the physics of matter under extreme conditions of temperature and pressure. We can now make good on that promise. Usi
Externí odkaz:
http://arxiv.org/abs/astro-ph/0108501
Publikováno v:
Astrophys.J.557:1021-1027,2001
For many years, astronomers have promised that the study of pulsating white dwarfs would ultimately lead to useful information about the physics of matter under extreme conditions of temperature and pressure. In this paper we finally make good on tha
Externí odkaz:
http://arxiv.org/abs/astro-ph/0104205
Publikováno v:
2001, ApJ, 548, L53
We consider envelopes of DB white dwarfs which are not composed of pure 4-He, but rather a mixture of 3-He and 4-He. Given this assumption, the same diffusive processes which produce a relatively pure H layer overlying a He layer in the DA's should w
Externí odkaz:
http://arxiv.org/abs/astro-ph/0011551