Royal Astronomical Society Press Release
RAS PN 10/24 (NAM 20) 16-Apr-2010
Observations of how the youngest-known neutron star has cooled over the past decade are giving astronomers new insights into the interior of these super-dense dead stars.
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Dr Ho, of the University of Southampton, and Dr Craig Heinke, of the University of Alberta in Canada, measured the temperature of the neutron star in the Cassiopeia A supernova remnant using data obtained by NASA’s Chandra X-ray Observatory between 2000 and 2009.
“This is the first time that astronomers have been able to watch a young neutron star cool steadily over time. Chandra has given us a snapshot of the temperature roughly every two years for the past decade and we have seen the temperature drop during that time by about 3%,” said Dr Ho.
Neutron stars are composed mostly of neutrons crushed together by gravity, compressed to over a million million times the density of lead. They are the dense cores of massive stars that have run out of nuclear fuel and collapsed in supernova explosions. The Cassiopeia A supernova explosion, likely to have taken place around 1680, would have heated the neutron star to temperatures of billions of degrees, from which it has cooled down to a temperature of about two million degrees Celsius.
Chandra: Cassiopeia A: Carbon Atmosphere Discovered On Neutron Star
(X-ray: NASA/CXC/Southampton/W. Ho et al; Illustration: NASA/CXC/M.Weiss)
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