Sensitivity of the neutron star r-mode instability window to the density dependence of the nuclear symmetry energy

Details Sensitivity of the neutron star r-mode instability window to the density dependence of the nuclear symmetry energy Sensitivity of the neutron star r-mode instability window to the density dependence of the nuclear symmetry energy

2011-10-27

arxiv.org/abs/1110.5985v2

Astronomy and Astrophysics

Astrophysics

Solar and Stellar Astrophysics

10 pages, 6 figures, accepted for publication in Physical Review C

Scientific paper

Using a simple model of a neutron star with a perfectly rigid crust constructed and a set of crust and core equations of state that span the range of nuclear experimental uncertainty in the density dependence of the symmetry energy from 25 MeV (soft EOS) to 115 MeV (stiff EOS), we calculate the instability window for the onset of the Chandrasekhar-Friedmann-Schutz (CFS) instability in r-mode oscillations for canonical neutron stars (1.4 M_{\odot}) and massive neutron stars (2.0 M_{\odot}). In these models the crust-core transition density, and thus crustal thickness, is calculated consistently with the core equation of state (EOS). For the canonical neutron star, the lower bound of the r-mode instability window is reduced in frequency by \approx150 Hz from the softest to the stiffest symmetry energy used, independent of mass and temperature. The instability window also drops by \approx 100 Hz independent of EOS when the mass is raised from 1.4 M_{\odot} to 2.0 M_{\odot}. Where temperature estimates are available, the observed neutron stars in low mass X-ray binaries (LMXBs) have frequencies below the instability window for the 1.4 M_{\odot} models, while some LMXBs fall within the instability window for 2.0 M_{\odot} stars if the symmetry energy is relatively stiff, indicating that a softer symmetry energy is more consistent with observations within this model. Thus we conclude that smaller values of L help stabilize neutron stars against runaway r-mode oscillations. The critical temperature, below which no star can reach the instability window without exceeding its Kepler frequency, varies by nearly an order of magnitude from soft to stiff symmetry energies. When the crust thickness and core EOS are treated consistently, a thicker crust corresponds to a lower critical temperature, the opposite result to previous studies in which the transition density was independent of the core EOS.

Affiliated with

Also associated with

No associations

Rating

Sensitivity of the neutron star r-mode instability window to the density dependence of the nuclear symmetry energy does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Sensitivity of the neutron star r-mode instability window to the density dependence of the nuclear symmetry energy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sensitivity of the neutron star r-mode instability window to the density dependence of the nuclear symmetry energy will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-375431