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DC Field | Value | Language |
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dc.citation.number | 2 | - |
dc.citation.startPage | 115 | - |
dc.citation.title | ASTROPHYSICAL JOURNAL | - |
dc.citation.volume | 907 | - |
dc.contributor.author | Takata, J. | - |
dc.contributor.author | Wang, X. F. | - |
dc.contributor.author | Wang, H. H. | - |
dc.contributor.author | Lin, L. C-C | - |
dc.contributor.author | Hu, C-P | - |
dc.contributor.author | Li, K. L. | - |
dc.contributor.author | Kong, A. K. H. | - |
dc.date.accessioned | 2023-12-21T16:15:51Z | - |
dc.date.available | 2023-12-21T16:15:51Z | - |
dc.date.created | 2021-03-16 | - |
dc.date.issued | 2021-02 | - |
dc.description.abstract | We report a study of X-ray emission from the white dwarf/M-type star binary system AR Scorpii using archival data taken in 2016-2020. It has been known that the X-ray emission is dominated by optically thin thermal plasma emission and its flux level varies significantly over the orbital phase. The X-ray emission also contains a component that modulates with the beat frequency between the white dwarf's spin frequency and orbital frequency. In this new analysis, the 2020 data taken by NICER shows that the X-ray emission modulates with the spin frequency as well as with the beat frequency, indicating that part of the X-ray emission comes from the white dwarf's magnetosphere. It is found that the signal of the spin frequency appears only at a specific orbital phase, while the beat signal appears over the orbital phase. We interpret the X-ray emission modulating with the spin frequency and the beat frequency as a result of synchrotron emission from electrons with smaller and larger pitch angles, respectively. In the long-term evolution, the beat pulse profile averaged over the orbital phase changes from a single-peak structure in 2016/2018 to a double-peak structure in 2020. The observed X-ray flux levels measured in 2016/2017 are higher than those measured in 2018/2020. The plasma temperature and the amplitude of the orbital waveform might vary with time too. These results indicate that the X-ray emission from AR Scorpii evolves on a timescale of years. This long-term evolution would be explained by a superorbital modulation related to, for example, a precession of the white dwarf or a fluctuation of the system related to the activity of the companion star. | - |
dc.identifier.bibliographicCitation | ASTROPHYSICAL JOURNAL, v.907, no.2, pp.115 | - |
dc.identifier.doi | 10.3847/1538-4357/abd0f8 | - |
dc.identifier.issn | 0004-637X | - |
dc.identifier.scopusid | 2-s2.0-85101342787 | - |
dc.identifier.uri | https://scholarworks.unist.ac.kr/handle/201301/50174 | - |
dc.identifier.url | https://iopscience.iop.org/article/10.3847/1538-4357/abd0f8 | - |
dc.identifier.wosid | 000615224600001 | - |
dc.language | 영어 | - |
dc.publisher | IOP PUBLISHING LTD | - |
dc.title | An X-Ray Study of the White Dwarf Binary AR Scorpii | - |
dc.type | Article | - |
dc.description.isOpenAccess | FALSE | - |
dc.relation.journalWebOfScienceCategory | Astronomy & Astrophysics | - |
dc.relation.journalResearchArea | Astronomy & Astrophysics | - |
dc.type.docType | Article | - |
dc.description.journalRegisteredClass | scie | - |
dc.description.journalRegisteredClass | scopus | - |
dc.subject.keywordAuthor | White dwarf stars | - |
dc.subject.keywordAuthor | Binary stars | - |
dc.subject.keywordAuthor | X-ray binary stars | - |
dc.subject.keywordAuthor | Non-thermal radiation sources | - |
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