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| Paper: |
Thermal Evolution of Neutron Stars: Current Status |
| Volume: |
451, 9th Pacific Rim Conference on Stellar Astrophysics |
| Page: |
239 |
| Authors: |
Tsuruta, S. |
| Abstract: |
Since the first detection of thermal radiation directly from the
stellar surface of four pulsars by ROSAT, number of neutron stars with
detected thermal radiation has increased significantly. By
carefully analyzing the data and comparing the results with
thermal evolution theories, we now have realistic hope for
exploring the composition of ultrahigh density matter. Currently,
the data of Vela pulsar already suggest that the core of high mass
neutron stars should include such exotic particles as hyperons
and/or pion condensates. However, to confirm such possibilities,
more such data for more pulsars are badly needed. Fortunately, it
was found recently that soft X-ray transients (SXT) in low-mass
X-ray binaries (LMXB) can provide additional such extra data when
they are in quiescence.
These data helped us better understand the composition
of neutron star crusts and atmospheres also. From careful analysis of
the very recent data from very long Chandra observations of the neutron star
in Cassiopeia A (Cas A) supernova remnant, its temperature, not just the upper limit,
was determined. Moreover, further analysis of its archival data from
observations over long period of time (∼ 10 years), has led to the
striking finding that this neutron star is cooling rapidly. Its implication could help
us reach deeper insight to the nature of neutron stars.
We will summarize
these developments, and emphasize those future observatories such
as ASTRO-H will mean breakthroughs in this exciting area. |
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