The cosmic production of Helium

Authors:
Raul Jimenez (UPenn),
Chris Flynn (Turku and Swinburne Universities),
James MacDonald (U. of Delaware),
Brad K. Gibson (Swinburne University)

Comments: Published in Science Mar 7 2003: 1552-1555

We estimate the cosmic production rate of helium relative to metals ($Delta
Y/Delta Z$) using K dwarf stars in the Hipparcos catalog with accurate
spectroscopic metallicities. The best fitting value is $Delta Y/Delta Z=2.1
pm 0.4$ at the 68% confidence level. Our derived value agrees with
determinations from HII regions and with theoretical predictions from stellar
yields with standard assumptions for the initial mass function. The amount of
helium in stars determines how long they live and therefore how fast they will
enrich the insterstellar medium with fresh material.

References and citations for this submission:

SLAC-SPIRES HEP (refers to ,
cited by, arXiv reformatted)