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arXiv · astro-ph/0607650

The Hydrogen Burning Turn-off of RS Ophiuchi 2006

Izumi Hachisu·Mariko Kato·Seiichiro Kiyota·Katsuaki Kubotera·Hiroyuki Maehara·Kazuhiro Nakajima·Yuko Ishii·Mari Kamada·Sahori Mizoguchi·Shinji Nishiyama·Naoko Sumitomo·Ken'ichi Tanaka·Masayuki Yamanaka·Kozo Sadakane
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Abstract

We report a coordinated multi-band photometry of the RS Oph 2006 outburst and highlight the emission line free y-band photometry that shows a mid-plateau phase at y ~ 10.2 mag from day 40 to day 75 after the discovery followed by a sharp drop of the final decline. Such mid-plateau phases are observed in other two recurrent novae, U Sco and CI Aql, and are interpreted as a bright disk irradiated by the white dwarf. We have calculated theoretical light curves based on the optically thick wind theory and have reproduced the observed light curves including the mid-plateau phase and the final sharp decline. This final decline is identified with the end of steady hydrogen shell-burning, which turned out the day ~80. This turnoff date is consistent with the end of a supersoft X-ray phase observed with Swift. Our model suggests a white dwarf mass of 1.35 \pm 0.01 M_\sun, which indicates that RS Oph is a progenitor of Type Ia supernovae. We strongly recommend the y-filter observation of novae to detect both the presence of a disk and the hydrogen burning turn-off.

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Izumi Hachisu, Mariko Kato, Seiichiro Kiyota, Katsuaki Kubotera, Hiroyuki Maehara, Kazuhiro Nakajima, Yuko Ishii, Mari Kamada, Sahori Mizoguchi, Shinji Nishiyama, Naoko Sumitomo, Ken'ichi Tanaka, Masayuki Yamanaka, Kozo Sadakane. 2006-09-22. The Hydrogen Burning Turn-off of RS Ophiuchi 2006. https://doi.org/10.1086/509615

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