Uday K. Gurugubelli^1,2, D. K. Sahu², G. C. Anupama² and N. K. Chakradhari^2
1Joint Astronomy Programme, Indian Institute of Science, Bangalore, India
²Indian Institute of Astrophysics, Bangalore, India

Abstract. We present optical photometry and spectroscopy of the normal type IIP supernova SN2004A, which was discovered in the galaxy NGC 6207 on 2004 January 9.84UT. Early observations indicated that the supernova was discovered at about two weeks since explosion. We estimate the distance to NGC 6207 to be 20.35 ± 4.5 Mpc using the Standard Candle method. Using this distance, we estimate the ejected nickel mass in the explosion to be 0.032 ± 0.02 M_Θ. The plateau luminosity, its duration (about 80 days) and the expansion velocity of the supernova ejecta at the middle of the plateau indicate an explosion energy of 4.7 ± 2.7 × 10⁵⁰ ergs and an ejected envelope mass of 7.2 ± 2.2 M_Θ. The ejected envelope mass implies a main sequence mass of 10 ± 2.5M_Θ for the progenitor.

Keywords: Stars: evolution -- supernovae: general -- supernovae: individual: SN~2004A -- galaxies: individual: NGC~6207 -- galaxies: distances and redshifts

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