A changing wind collision
| Autor: | Naze, Yael, Koenigsberger, Gloria, Pittard, Julian M., Parkin, Elliot Ross, Rauw, Gregor, Corcoran, Michael F., Hillier, D. John |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | ApJ, 853, 164 (11p, 2018) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/1538-4357/aaa29c |
| Popis: | We report on the first detection of a global change in the X-ray emitting properties of a wind-wind collision, thanks to XMM-Newton observations of the massive SMC system HD5980. While its lightcurve had remained unchanged between 2000 and 2005, the X-ray flux has now increased by a factor of ~2.5, and slightly hardened. The new observations also extend the observational coverage over the entire orbit, pinpointing the lightcurve shape. It has not varied much despite the large overall brightening, and a tight correlation of fluxes with orbital separation is found, without any hysteresis effect. Moreover, the absence of eclipses and of absorption effects related to orientation suggests a large size for the X-ray emitting region. Simple analytical models of the wind-wind collision, considering the varying wind properties of the eruptive component in HD5980, are able to reproduce the recent hardening and the flux-separation relationship, at least qualitatively, but they predict a hardening at apastron and little change in mean flux, contrary to observations. The brightness change could then possibly be related to a recently theorized phenomenon linked to the varying strength of thin-shell instabilities in shocked wind regions. Comment: accepted by ApJ |
| Databáze: | arXiv |
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