The Hydrogen Burning Turn-off of RS Ophiuchi 2006

• Published in: arXiv.org 2006-09
• Main Authors: Hachisu, Izumi, Kato, Mariko, Kiyota, Seiichiro, Kubotera, Katsuaki, Maehara, Hiroyuki, Nakajima, Kazuhiro, Ishii, Yuko, Kamada, Mari, Mizoguchi, Sahori, Nishiyama, Shinji, Sumitomo, Naoko, Tanaka, Ken'ichi, Yamanaka, Masayuki, Sadakane, Kozo
• Format: Article
• Language: English
• Subjects: Hydrogen; Light curve; Novae; Photometry; Supernovae; White dwarf stars
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0607650

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.