From: LARRY KLAES (ljk4_at_msn.com)
Date: Mon Nov 27 2006 - 09:35:15 PST
Astrophysics, abstract
astro-ph/0611729
From: Renxin Xu [view email]
Date: Thu, 23 Nov 2006 03:35:18 GMT (32kb)
PSR B1828-11: a precession pulsar torqued by a quark planet?
Authors: K. Liu (PKU), Y. L. Yue (PKU), R. X. Xu (PKU)
Comments: 6 pages, 3 figures
The pulsar PSR B1828-11 has long-term, highly periodic and correlated
variations in both pulse shape and the rate of slow-down. This phenomenon
may provide evidence for precession of the pulsar as suggested previously
within the framework of free precession as well as forced one. Based on the
presumption of forced precession, we propose a quark planet model to this
precession phenomenon instead. In the model, the pulsar is torqued by a
quark planet. We construct this model by constraining mass of the pulsar
($M_{\rm psr}), mass of the planet ($M_{\rm pl}$) and orbital radius of the
planet ($r_{\rm pl}$). Five aspects are considered: derived relation between
$M_{\rm psr}$ and $r_{\rm pl}$, movement of the pulsar around the center of
mass, ratio of $M_{\rm psr}$ and $M_{\rm p}$, gravitational wave radiation
timescale of the planetary system, and death-line criterion. We also
calculate the range of precession period derivative and gravitational wave
strength (at earth) by the model. Under reasonable parameters, the observed
phenomenon can be understood by a pulsar ($10^{-4}\sim10^{-1}M_{\odot}$)
with a quark planet ($10^{-8}\sim10^{-3}M_{\odot}$) orbiting it. According
to the calculations presented, the pulsar would be a quark star because of
its low mass, which might eject a lump of quark matter (to become a planet
around) during its birth.
http://arxiv.org/abs/astro-ph/0611729
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