Details

Autor(en) / Beteiligte

• Morii, M
• Tomida, H
• Kimura, M
• Suwa, F
• Negoro, H
• Serino, M
• Kennea, J A
• Page, K L
• Curran, P A
• Walter, F M

Titel

EXTRAORDINARY LUMINOUS SOFT X-RAY TRANSIENT MAXI J0158-744 AS AN IGNITION OF A NOVA ON A VERY MASSIVE O-Ne WHITE DWARF

Ist Teil von

• The Astrophysical journal, 2013-12, Vol.779 (2), p.1-13

Ort / Verlag

United States

Erscheinungsjahr

2013

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• We present the observation of an extraordinary luminous soft X-ray transient, MAXI J0158-744, by the Monitor of All-sky X-ray Image (MAXI) on 2011 November 11. This transient is characterized by a soft X-ray spectrum, a short duration (1.3 x 10 super(3) s < Delta T sub(d) < 1.10 x 10 super(4) s), a rapid rise (<5.5 x 10 super(3) s), and a huge peak luminosity of 2 x 10 super(40) erg s super(-1) in 0.7-7.0 keV band. With Swift observations and optical spectroscopy from the Small and Moderate Aperture Research Telescope System, we confirmed that the transient is a nova explosion, on a white dwarf in a binary with a Be star, located near the Small Magellanic Cloud. An early turn-on of the super-soft X-ray source (SSS) phase (<0.44 days), the short SSS phase duration of about one month, and a 0.92 keV neon emission line found in the third MAXI scan, 1296 s after the first detection, suggest that the explosion involves a small amount of ejecta and is produced on an unusually massive O-Ne white dwarf close to, or possibly over, the Chandrasekhar limit. We propose that the huge luminosity detected with MAXI was due to the fireball phase, a direct manifestation of the ignition of the thermonuclear runaway process in a nova explosion.