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Query : 2009A&A...502..605H |

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2009A&A...502..605H -
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Astronomy and Astrophysics, volume 502, 605-610 (2009/8-1)
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Keplerian frequency of uniformly rotating neutron stars and strange stars.
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HAENSEL P., ZDUNIK J.L., BEJGER M. and LATTIMER J.M.
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Abstract (from CDS):
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We calculate Keplerian (mass shedding) configurations of rigidly rotating neutron stars and strange stars with crusts. We check the validity of the empirical formula for Keplerian frequency, f_{K}, proposed by Lattimer & Prakash (2004Sci...304..536L), f_{K}(M)=C(M/M_{☉})^{1/2}(R/10km)^{–3/2}, where M is the (gravitational) mass of the Keplerian configuration, R is the (circumferential) radius of the non-rotating configuration of the same gravitational mass, and C=1.04kHz. Numerical calculations are performed using precise 2D codes based on the multi-domain spectral methods. We use a representative set of equations of state (EOSs) of neutron stars and quark stars. We show that the empirical formula for f_{K}(M) holds within a few percent for neutron stars with realistic EOSs, provided 0.5M_{☉}<M<0.9M_{max}^{stat}, where M_{max}^{stat} is the maximum allowable mass of non-rotating neutron stars for an EOS, and C=C_{NS}=1.08kHz. Similar precision is obtained for strange stars with 0.5M_{☉}<M<0.9M_{max}^{stat}. For maximal crust masses we obtain C_{SS}=1.15kHz, and the value of C_{SS} is not very sensitive to the crust mass. All our Cs are significantly larger than the analytic value from the relativistic Roche model, C_{Roche}=1.00kHz. For 0.5M_{☉}<M<0.9M_{max}^{stat}, the equatorial radius of the Keplerian configuration of mass M, R_{K}(M), is, to a very good approximation, proportional to the radius of the non-rotating star of the same mass, R_{K}(M)=a R(M), with a_{NS}≃a_{SS}≃1.44. The value of a_{SS} is very weakly dependent on the mass of the crust of the strange star. Both a values are smaller than the analytic value a_{Roche}=1.5 from the relativistic Roche model.

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Abstract Copyright:
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Journal keyword(s):
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dense matter - equation of state - stars: neutron - stars: rotation
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Simbad objects:
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3

Number of rows : 3 |

N | Identifier | Otype |
ICRS (J2000) RA |
ICRS (J2000) DEC |
Mag U | Mag B | Mag V | Mag R | Mag I | Sp type |
#ref
1850 - 2022 |
#notes |
---|---|---|---|---|---|---|---|---|---|---|---|---|

1 | [KRL2007b] 258 | LXB | 17 39 53.95 | -28 29 46.8 | ~ | 86 | 0 | |||||

2 | PSR J1748-2446ad | Psr | 17 48 04.9 | -24 46 04 | ~ | 99 | 1 | |||||

3 | PSR B1937+21 | Psr | 19 39 39.6 | +21 37 22 | ~ | 1013 | 2 |

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2022.05.28-21:55:52

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