| タイトル | The X-ray Spectral Evolution of eta Carinae as Seen by ASCA |
| 本文（外部サイト） | http://hdl.handle.net/2060/20000118280 |
| 著者（英） | Fredericks, A. C.; Petre, R.; Corcoran, M. F.; White, Nicholas E.; Swank, J. H.; Drake, S. A. |
| 著者所属（英） | NASA Goddard Space Flight Center |
| 発行日 | 2000-01-01 |
| 言語 | eng |
| 内容記述 | Using data from the ASCA X-ray observatory, we examine the variations in the X-ray spectrum of the supermassive star nu Carinae with an unprecedented combination of spatial and spectral resolution. We include data taken during the recent X-ray eclipse in 1997-1998, after recovery from the eclipse, and during and after an X-ray flare. We show that the eclipse variation in the X-ray spectrum is apparently confined to a decrease in the emission measure of the source. We compare our results with a simple colliding wind binary model and find that the observed spectral variations are only consistent, with the binary model if there is significant high-temperature emission far from the star and/or a substantial change in the temperature distribution of the hot plasma. If contamination in the 2-10 keV band is important, the observed eclipse spectrum requires an absorbing column in excess of 10(exp 24)/sq cm for consistency with the binary model, which may indicate an increase in the first derivative of M from nu Carinae near the time of periastron passage. The flare spectra are consistent with the variability seen in nearly simultaneous RXTE observations and thus confirm that nu Carinae itself is the source of the flare emission. The variation in the spectrum during the flare seems confined to a change in the source emission measure. By comparing 2 observations obtained at the same phase in different X-ray cycles, we find that the current, X-ray brightness of the source is slightly higher than the brightness of the source during the last cycle perhaps indicative of a long-term increase in the first derivative of M, not associated with the X-ray cycle. |
| NASA分類 | Astronomy |
| 権利 | No Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/226531 |
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