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RX J1856.5-3754 and 3C58:
Cosmic X-rays May Reveal New Form of Matter
Chandra observations of RX J1856.5-3754 and the
pulsar in 3C58 suggest that the matter in these
collapsed stars is even denser than nuclear matter, the
most dense matter found on Earth. This raises the
possibility that these stars are composed of free
quarks or crystals of sub-nuclear particles, rather
than neutrons.
By combining Chandra and Hubble Space Telescope data,
astronomers found that RX J1856 radiates like a solid
body with a temperature of 700,000 degrees Celsius and
has a diameter of about 7 miles.
This size is too small to reconcile with the standard
models of neutron stars. One exciting possibility,
predicted by some theories, is that the neutrons in the
star have dissolved at very high density into a soup of
"up," "down" and "strange" quarks to form a "strange quark star," which would explain the smaller
radius.
Observations of 3C58, the remnant of a supernova noted
on Earth in AD 1181, reveal that the pulsar in the core
has a temperature much lower than expected. This
suggests that an exotic, denser state of matter might
exist inside this star as well.
These observations demonstrate that the universe can
be used as a laboratory to explore physics under
conditions that are not accessible on Earth.
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Fast Facts for RX
J1856.5-3754:
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Credit
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NASA/SAO/CXC/J.Drake et al.
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Scale
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Image is 20 arcsec on a side.
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Category
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Neutron
Stars/X-ray Binaries |
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Coordinates
(J2000)
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RA 18h 56m 35.3s | Dec -37º 56'
34.40" |
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Constellation
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Corona Australis
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Observation
Date
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March 10, 2000, and various times
between October 8, 2001 & October
15, 2001
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Observation
Time
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Total observation time 139.4 hours
(5.8 days)
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Obs.
ID
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113, 3382, 3380, 3381, 3399
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Color
Code
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Intensity
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Instrument
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HRC/LETG |
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Distance
Estimate
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400 light years
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Fast Facts for
3C58:
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Credit
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NASA/SAO/CXC/P.Slane et al.
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Scale
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Image is 7.2 arcmin on a side
(pullout box is 1.4 arcmin).
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Category
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Neutron Stars/X-ray Binaries
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Coordinates
(J2000)
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RA 02h 05m 37.00s | Dec +64º 49'
48.00" |
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Constellation
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Cassiopeia
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Observation
Date
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September 4, 2000
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Observation
Time
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9.4 hours
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Obs.
ID
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728
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Color
Code
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Intensity
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Instrument
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ACIS
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Distance
Estimate
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10,000 light years
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Release Date
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April 10, 2002
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