Early time optical spectroscopy of supernova SN 1998S
Indian Institute of Astrophysics, II Block Koramangala, Bangalore 560 034, India
Corresponding author: G. C. Anupama, email@example.com
Accepted: 4 December 2000
We present medium-resolution optical spectra of the type II supernova SN 1998S obtained during the pre-maximum, maximum and early decline phases. The early decline spectra show complex Balmer line profiles: a narrow P-Cygni emission feature superimposed on a broad emission. The narrow emission has a redshift similar to that of the host galaxy, indicating its origin from a pre-supernova circumstellar material. The Hα luminosity of the broad component implies a shell mass of ∼0.1 for the supernova ejecta, while the luminosity of the narrow component implies a mass loss rate of yr-1 for the precursor. The photospheric temperature of the supernova shell decreased from a value of K on day 17 to a value of K on day 44. The observations indicate SN 1998S belongs to type IIn supernovae where the supernova ejecta dynamically interact with a pre-supernova circumstellar material.
Key words: supernovae: general / supernovae: individual (SN 1998S)
© ESO, 2001