PROBING THE CRUST OF THE NEUTRON STAR IN EXO 0748-676
X-ray observations of quiescent X-ray binaries have the potential to provide insight into the structure and the composition of neutron stars. EXO 0748-676 had been actively accreting for over 24 yr before its outburst ceased in late 2008. Subsequent X-ray monitoring revealed a gradual decay of the q...
| Main Authors: | , , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
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IOP Publishing
2015
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| Online Access: | http://hdl.handle.net/1721.1/94579 |
| _version_ | 1811089138607194112 |
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| author | Degenaar, N. Medin, Z. Cumming, A. Wijnands, R. Wolff, M. T. Cackett, E. M. Miller, J. M. Jonker, P. G. Brown, E. F. Homan, Jeroen |
| author2 | MIT Kavli Institute for Astrophysics and Space Research |
| author_facet | MIT Kavli Institute for Astrophysics and Space Research Degenaar, N. Medin, Z. Cumming, A. Wijnands, R. Wolff, M. T. Cackett, E. M. Miller, J. M. Jonker, P. G. Brown, E. F. Homan, Jeroen |
| author_sort | Degenaar, N. |
| collection | MIT |
| description | X-ray observations of quiescent X-ray binaries have the potential to provide insight into the structure and the composition of neutron stars. EXO 0748-676 had been actively accreting for over 24 yr before its outburst ceased in late 2008. Subsequent X-ray monitoring revealed a gradual decay of the quiescent thermal emission that can be attributed to cooling of the accretion-heated neutron star crust. In this work, we report on new Chandra and Swift observations that extend the quiescent monitoring to [~ over _]5 yr post-outburst. We find that the neutron star temperature remained at [~ over _]117 eV between 2009 and 2011, but had decreased to [~ over _]110 eV in 2013. This suggests that the crust has not fully cooled yet, which is supported by the lower temperature ([~ over _]95 eV) measured [~ over _]4 yr prior to the accretion phase in 1980. Comparing the data to thermal evolution simulations reveals that the apparent lack of cooling between 2009 and 2011 could possibly be a signature of convection driven by phase separation of light and heavy nuclei in the outer layers of the neutron star. |
| first_indexed | 2024-09-23T14:14:18Z |
| format | Article |
| id | mit-1721.1/94579 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T14:14:18Z |
| publishDate | 2015 |
| publisher | IOP Publishing |
| record_format | dspace |
| spelling | mit-1721.1/945792022-10-01T19:57:34Z PROBING THE CRUST OF THE NEUTRON STAR IN EXO 0748-676 Degenaar, N. Medin, Z. Cumming, A. Wijnands, R. Wolff, M. T. Cackett, E. M. Miller, J. M. Jonker, P. G. Brown, E. F. Homan, Jeroen MIT Kavli Institute for Astrophysics and Space Research Homan, Jeroen X-ray observations of quiescent X-ray binaries have the potential to provide insight into the structure and the composition of neutron stars. EXO 0748-676 had been actively accreting for over 24 yr before its outburst ceased in late 2008. Subsequent X-ray monitoring revealed a gradual decay of the quiescent thermal emission that can be attributed to cooling of the accretion-heated neutron star crust. In this work, we report on new Chandra and Swift observations that extend the quiescent monitoring to [~ over _]5 yr post-outburst. We find that the neutron star temperature remained at [~ over _]117 eV between 2009 and 2011, but had decreased to [~ over _]110 eV in 2013. This suggests that the crust has not fully cooled yet, which is supported by the lower temperature ([~ over _]95 eV) measured [~ over _]4 yr prior to the accretion phase in 1980. Comparing the data to thermal evolution simulations reveals that the apparent lack of cooling between 2009 and 2011 could possibly be a signature of convection driven by phase separation of light and heavy nuclei in the outer layers of the neutron star. 2015-02-18T14:41:52Z 2015-02-18T14:41:52Z 2014-07 2014-03 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/94579 Degenaar, N., Z. Medin, A. Cumming, R. Wijnands, M. T. Wolff, E. M. Cackett, J. M. Miller, P. G. Jonker, J. Homan, and E. F. Brown. “PROBING THE CRUST OF THE NEUTRON STAR IN EXO 0748-676.” The Astrophysical Journal 791, no. 1 (July 25, 2014): 47. © 2014 The American Astronomical Society en_US http://dx.doi.org/10.1088/0004-637x/791/1/47 The Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf IOP Publishing American Astronomical Society |
| spellingShingle | Degenaar, N. Medin, Z. Cumming, A. Wijnands, R. Wolff, M. T. Cackett, E. M. Miller, J. M. Jonker, P. G. Brown, E. F. Homan, Jeroen PROBING THE CRUST OF THE NEUTRON STAR IN EXO 0748-676 |
| title | PROBING THE CRUST OF THE NEUTRON STAR IN EXO 0748-676 |
| title_full | PROBING THE CRUST OF THE NEUTRON STAR IN EXO 0748-676 |
| title_fullStr | PROBING THE CRUST OF THE NEUTRON STAR IN EXO 0748-676 |
| title_full_unstemmed | PROBING THE CRUST OF THE NEUTRON STAR IN EXO 0748-676 |
| title_short | PROBING THE CRUST OF THE NEUTRON STAR IN EXO 0748-676 |
| title_sort | probing the crust of the neutron star in exo 0748 676 |
| url | http://hdl.handle.net/1721.1/94579 |
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