Year: 2007
Type: article
Abstract: We have derived a primordial helium abundance of Y p = 0.2477 ± 0.0029, based on new atomic physics computations of the recombination coefficients of He I and of the collisional excitation of the H I Balmer lines together with observations and photoionization models of metal-poor extragalactic H II regions. The new atomic data increase our previous determination of Y p by 0.0086, a very significant amount. By combining our Y p result with the predictions made by the standard big bang nucleosynthesis model, we find a baryon-to-photon ratio, η, in excellent agreement both with the η-value derived by the primordial deuterium abundance value observed in damped Lyα systems and with the one obtained from the WMAP observations.
Source: The Astrophysical Journal
DOI: 10.1086/520571
Authors: Manuel Peimbert, Valentina Luridiana, Antonio Peimbert
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2079337104