A key factor to the spin parameter of uniformly rotating compact stars: crust structure

• 来源期刊: 天文和天体物理学研究
• 年，卷（期）: 2016,（4）
• 页码范围: 63-70
• 页数: 8页
• 语种: 英文
• DOI: 10.1088/1674-4527/16/4/060

摘要

We study the dimensionless spin parameter j ≡ cJ/(GM2) of different kinds of uniformly rotating compact stars,including traditional neutron stars,hyperonic neutron stars and hybrid stars,based on relativistic mean field theory and the MIT bag model.It is found that jmax ～ 0.7,which had been suggested in traditional neutron stars,is sustained for hyperonic neutron stars and hybrid stars with M ＞0.5 M☉.Not the interior but rather the crust structure of the stars is a key factor to determine jmax for three kinds of selected compact stars.Furthermore,a universal formula j =0.63(f/fK)-0.42(f/fK)2 +0.48(f/fK)a is suggested to determine the spin parameter at any rotational frequency f smaller than the Keplerian frequency fK.