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X-RAY ECLIPSE DIAGNOSIS OF THE EVOLVING MASS LOSS IN THE RECURRENT NOVA U SCORPII 2010

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journal contribution
posted on 01.02.2016, 12:39 by D. Takei, J. J. Drake, M. Tsujimoto, J-U. Ness, Julian Paul Osborne, S. Starrfield, S. Kitamoto
We report the Suzaku detection of the earliest X-ray eclipse seen in the recurrent nova U Scorpii 2010. A target-of-opportunity observation 15 days after the outburst found a 27% ± 5% dimming in the 0.2-1.0 keV energy band at the predicted center of an eclipse. In comparison with the X-ray eclipse depths seen at two later epochs by XMM-Newton, the source region shrank by about 10%-20% between days 15 and 35 after the outburst. The X-ray eclipses appear to be deeper than or similar to contemporaneous optical eclipses, suggesting the X-ray and optical source region extents are comparable on day 15. We raise the possibility of the energy dependency in the photon escape regions, and that this would be a result of the supersoft X-ray opacity being higher than the Thomson scattering opacity at the photosphere due to bound-free transitions in abundant metals that are not fully ionized. Assuming a spherically symmetric model, we constrain the mass-loss rate as a function of time. For a ratio of actual to Thomson opacity of 10-100 in supersoft X-rays, we find an ejecta mass of about 10[Superscript: –7]-10[Superscript: –6] M ☉.

History

Citation

Astrophysical Journal Letters, 2013, 769 (1), L4

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Astrophysical Journal Letters

Publisher

IOP Publishing LTD

issn

2041-8205

eissn

2041-8213

Acceptance date

20/03/2013

Copyright date

2013

Available date

01/02/2016

Publisher version

http://iopscience.iop.org/article/10.1088/2041-8205/769/1/L4/meta

Language

en