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KS 1731-260:
A Cool Neutron Star in the Constellation Ophiuchus
Chandra' s observation in March of
2001 of the neutron star KS 1731-260 (pale blue dot
just above the middle of the image) showed that it is a
remarkably 'cool' 3 million degrees Celsius.
This low temperature was surprising because in the
period 1988 to 2000 the neutron star was shining
brightly in X-rays due to the heavy bombardment of gas
from a companion star, not visible here. A neutron star
temperature of 10 million degrees or more was
expected.
A possible explanation for the relatively low
temperature of KS 1731-260 in its present quiet state
is that it was in a deep freeze for a thousand years
before 1988 and took 12 years of heating just to get to
the temperature it is today. If so, it may represent a
new type of neutron star system that stops accreting
gas for a long period of time, and there could be
hundreds of undetected, cold neutron stars in our
Galaxy.
| Fast Facts for KS 1731-260: |
| Credit |
NASA/CXC/Wijnands et al. |
| Scale |
Image is 1 arcmin on a side. |
| Category |
Neutron Stars/X-ray Binaries |
| Coordinates (J2000) |
RA 17h 34m 13.5s | Dec -26° 05' 16.8 |
| Constellation |
Ophiuchus |
| Observation Dates |
March 27 2001
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| Observation Time |
6 hours |
| Obs. IDs |
2428
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| Color Code |
Intensity |
| Instrument |
ACIS |
| Distance Estimate |
About 23,000 light years |
| Release Date |
September 06, 2001 |
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