An Extremely Massive White Dwarf of the Symbiotic Classical Nova V407 Cyg as Suggested by the RS Oph and U SCO Models

Open Astronomy

Kato M.¹  Hachisu I.² 

[1] Department of Astronomy, Keio University, Yokohama 223-8521, Japan;Department of Earth Science and Astronomy, College of Arts and Sciences, Uni. of Tokyo, Tokyo 153-8902, Japan;

关键词: binaries;    symbiotic;    novae;    cataclysmic variables;    stars;    individual (rs oph;    u sco;    v407 cyg);    white dwarfs;   

DOI  :  10.1515/astro-2017-0360

来源: DOAJ

【 摘 要 】

We have analyzed the optical light curve of the symbiotic star V407 Cyg that underwent a classical nova outburst in 2010 March. Being guided by a supersoft X-ray phase observed during days 20-40 after the nova outburst, we are able to reproduce the light curve during a very early phase of the nova outburst. Our model consists of an outbursting white dwarf and an extended equatorial disk. An extremely massive white dwarf of 1.35-1.37 M⊙ is suggested. the optical light curve is also consistent with a sharp drop 47 days after the outburst, which is the end of hydrogen shell-burning on the white dwarf. Although the extremely massive white dwarf is favourable to the interpretation that V407 Cyg is a recurrent nova, enrichment of heavy elements in the ejecta suggests that the white dwarf is eroded and, as a result, its mass is not increasing. Therefore, V407 Cyg may not explode as a Type Ia supernova even if it is a carbon-oxygen white dwarf.

【 授权许可】

Unknown