| タイトル | Identification and properties of the M giant/X-ray system HD 154791 = 2A 1704+241 |
| 著者（英） | Baliunas, S. L.; Garcia, M.; Elvis, M.; Schwartz, D.; Doxsey, R.; Watson, M. G.; Patterson, J.; Fabbiano, G.; Koenigsberger, G.; Swank, J. |
| 著者所属（英） | Leicester Univ.|Harvard-Smithsonian Center for Astrophysics|Massachusetts Inst. of Tech.|Pennsylvania State Univ.|NASA Goddard Space Flight Center |
| 発行日 | 1983-04-01 |
| 言語 | eng |
| 内容記述 | The Aerial V X-ray source 2A 1704+241 (= 4U 1700+24 = 3A 1703+241) is identified with the M3 II star HD 154791. The identification is based on a precise X-ray position determined by the HEAO 1 scanning modulation collimator and the Einstein Observatory imaging proportional counter, together with a spectrum measured by the International Ultraviolet Explorer. The ultraviolet spectrum shows strong emission of C IV 1550 A, N v 1238 A, and Mg II 2800 A, which is very unusual among M giants. This is the first X-ray detection of an M giant which has a completely normal optical spectrum. The X-ray luminosity reaches three orders of magnitude above the mean upper limit for the coronal X-ray flux from M giants. Although there is no direct evidence for a binary system, since radial velocity variations have not been observed, it is shown that a plausible neutron star binary model can be constructed. |
| NASA分類 | ASTROPHYSICS |
| レポートNO | 83A26730 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/404971 |
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