Paper: astro-ph/0605117
Date: Thu, 4 May 2006 06:29:07 GMT (147kb)

Title: A Neutron Star in F-sharp

Authors: Jonathan E. Grindlay

Comments: Invited Perspective for Science; 3 pages, 3 figures

Journal-ref: Science, 311, 1876 (2006)
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In this short introductory commentary on the paper (Hessels et al 2006,
Science, 311, 1901) reporting the discovery of the shortest spin period
millisecond pulsar (MSP) Ter5-ad in the globular cluster Terzan 5, I also point
out a new explanation for possible minimum spin periods, P, of MSPs without
requiring gravitational radiation (or other) slow-down torques. If the
accretion of matter required to spinup a MSP also reduces (buries) the neutron
star (NS) magnetic field, B, as commonly believed, an inverse correlation
between neutron star mass, M, and B is expected together with a positive
correlation between P and B. Both are suggested for the 4 MSPs with NS mass
measures reported (Latimer and Prakash 2004, Science, 304, 536) to have <~10%
uncertainties. The correlations imply the Ter5-ad NS has ~2.5 Msun, B ~5 x 10^7
G and thus Pdot ~3 x 10^-21 s/s -- which can be tested when a timing solution
is found. If confirmed, the highest spin frequency NSs do not pulse simply
because their B fields are too low.

\\ ( http://arXiv.org/abs/astro-ph/0605117 , 147kb)