The 'outside-in' outburst of HT Cassiopeiae期刊界 All Journals 搜尽天下杂志传播学术成果专业期刊搜索期刊信息化学术搜索

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The 'outside-in' outburst of HT Cassiopeiae

Authors:	Zach Ioannou T Naylor W F Welsh M S Catalán W J Worraker N D James

Institution:	Keele University, Department of Physics, Keele, Staffordshire ST5 5BG; University of Texas, Department of Astronomy, Austin, TX 78712, USA; University of St Andrews, Department of Physics and Astronomy, North Haugh, St Andrews, Fife KY16 9SS; 65 Wantage Road, Didcot, Oxfordshire OX11 0AE; 11 Tavistock Road, Chelmsford, Essex CM1 6JL

Abstract:	We present results from photometric observations of the dwarf nova system HT Cas during the eruption of 1995 November. The data include the first two-colour observations of an eclipse on the rise to outburst. They show that during the rise to outburst the disc deviates significantly from steady-state models, but the inclusion of an inner-disc truncation radius of about 4 R _wd and a 'flared' disc of semi-opening angle of 10° produces acceptable fits. The disc is found to have expanded at the start of the outburst to about 0.41 R _L1, as compared with quiescent measurements. The accretion disc then gradually decreases in radius reaching < 0.32 R _L1 during the last stages of the eruption. Quiescent eclipses were also observed prior to and after the eruption and a revised ephemeris is calculated.

Keywords:	accretion accretion discs binaries: close binaries: eclipsing stars: individual: HT Cas novae cataclysmic variables