Open AccessSN 1998A: explosion of a blue supergiant
Author(s) -
Pastorello A.,
Baron E.,
Branch D.,
Zampieri L.,
Turatto M.,
Ramina M.,
Benetti S.,
Cappellaro E.,
Salvo M.,
Patat F.,
Piemonte A.,
Sollerman J.,
Leibundgut B.,
Altavilla G.
Publication year - 2005
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2005.09079.x
Subject(s) - physics , supernova , supergiant , astrophysics , red supergiant , light curve , radius , spectral line , astronomy , stars , computer security , computer science
We present spectroscopic and photometric observations of the peculiar Type II supernova (SN) 1998A. The light curves and spectra closely resemble those of SN 1987A, suggesting that the SN 1998A progenitor exploded when it was a compact blue supergiant. However, the comparison with SN 1987A also highlights some important differences: SN 1998A is more luminous and the spectra show bluer continua and larger expansion velocities at all epochs. These observational properties indicate that the explosion of SN 1998A is more energetic than SN 1987A and more typical of Type II supernovae. Comparing the observational data with simulations, we deduce that the progenitor of SN 1998A was a massive star (∼25 M ⊙ ) with a small pre‐supernova radius (≲6 × 10 12 cm) . The Ba ii lines, unusually strong in SN 1987A and some faint II‐P events, are almost normal in the case of SN 1998A, indicating that the temperature plays a key role in determining their strength.