Possible Systematic Decreases in the Age of Globular Clusters

Дата и время публикации : 1994-03-29T21:01:43Z

Авторы публикации и институты :
X. Shi
D. N. Schramm
D. S. P. Dearborn
J. W. Truran

Оригинал статьи :http://arxiv.org/abs/astro-ph/9403064v1

Скачать pdf : http://arxiv.org/pdf/astro-ph/9403064v1

Ссылка на журнал-издание: Comments Astrophys. 17 (1995) 343-360
Коментарии к статье: revtex 17 pages, 4 figures upon request, FERMILAB-PUB-94/060-A
Первичная категория: astro-ph

Все категории : astro-ph

Краткий обзор статьи: The ages of globular clusters inferred from observations depends sensitively on assumptions like the initial helium abundance and the mass loss rate. A high helium abundance (e.g., $Yapprox$0.28) or a mass loss rate of $sim$10$^{-11}M_odot$ yr$^{-1}$ near the main sequence turn-off region lowers the current age estimate from 14 Gyr to about 10–12 Gyr, significantly relaxing the constraints on the Hubble constant, allowing values as high as 60km/sec/Mpc for a universe with the critical density and 90km/sec/Mpc for a baryon-only universe. Possible mechanisms for the helium enhancement in globular clusters are discussed, as are arguments for an instability strip induced mass loss near the turn-off. Ages lower than 10 Gyr are not possible even with the operation of both of these mechanisms unless the initial helium abundance in globular clusters is $>0.30$, which would conflict with indirect measurements of helium abundances in globular clusters.

Category: Physics