The ATNF Pulsar Catalogue (Manchester et al

PHYSICS · Multi-part · Fermi University Physics · Relativity & Gravitation · Astrophysics & Cosmology · Stellar death and compact objects

Stars from the Inside, Ch Neutron stars and pulsars: the densest matter, the maximum mass and the spinning magnet

Problem

The ATNF Pulsar Catalogue (Manchester et al. 2005, http://www.atnf.csiro.au/research/pulsar/psrcat) lists, among many others, the measured period PP and period derivative P˙\dot P of three pulsars. PSR B0833−-45 (Vela): P=89.3 msP = 89.3\,\mathrm{ms}, P˙=1.25×10−13\dot P = 1.25\times10^{-13}; PSR J0437−-4715: P=5.757 msP = 5.757\,\mathrm{ms}, P˙=5.73×10−20\dot P = 5.73\times10^{-20}; PSR J1622−-4950: P=4.3261 sP = 4.3261\,\mathrm{s}, P˙=1.7×10−11\dot P = 1.7\times10^{-11}. Using the surface-field estimate B=3.2×1015PP˙ TB = 3.2\times10^{15}\sqrt{P\dot P}\,\mathrm{T} (SI, PP in seconds) and the characteristic age τc=P/2P˙\tau_c = P/2\dot P, both derived for magnetic-dipole spin-down, ((a)) compute BB and τc\tau_c for each of the three pulsars; ((b)) place each pulsar in one of three populations, ordinary young pulsar, recycled millisecond pulsar, or magnetar, giving the numbers that justify each assignment. Compare with the Crab's B=3.8×108 TB = 3.8\times10^{8}\,\mathrm{T}, τc=1260 yr\tau_c = 1260\,\mathrm{yr} and with the millisecond-pulsar benchmark B≈2×104 TB \approx 2\times10^{4}\,\mathrm{T}, τc≈8×109 yr\tau_c \approx 8\times10^{9}\,\mathrm{yr}.

Browse the problem library