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arXiv · 1011.3563

The spin parameter of uniformly rotating compact stars

Ka-Wai Lo·Lap-Ming Lin
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Abstract

We study the dimensionless spin parameter $j (= c J/ (G M^2))$ of uniformly rotating neutron stars and quark stars in general relativity. We show numerically that the maximum value of the spin parameter of a neutron star rotating at the Keplerian frequency is $j_{\rm max} \sim 0.7$ for a wide class of realistic equations of state. This upper bound is insensitive to the mass of the neutron star if the mass of the star is larger than about $1 M_\odot$. On the other hand, the spin parameter of a quark star modeled by the MIT bag model can be larger than unity and does not have a universal upper bound. Its value also depends strongly on the bag constant and the mass of the star. Astrophysical implications of our finding will be discussed.

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Ka-Wai Lo, Lap-Ming Lin. 2011-01-21. The spin parameter of uniformly rotating compact stars. https://doi.org/10.1088/0004-637x%2F728%2F1%2F12

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