E. Muller et P. Hoflich, A COMPARISON OF CALCULATED AND OBSERVED MONOCHROMATIC TYPE-IA SUPERNOVA LIGHT CURVES, Astronomy and astrophysics, 281(1), 1994, pp. 51-65
The calculated monochromatic (B and V) light curves of a set of Type I
a supernova models are compared with the observed monochromatic light
curves of 13 Type Ia supernovae (SNIa). The set consists of 11 Type Ia
supernova models including deflagrations, detonations, delayed detona
tions, pulsating delayed detonations and tamped detonations. The theor
etical light curves have been calculated using our recently developed
light curve model. The model incorporates a detailed equation of state
with an elaborate treatment of the ionization balance, an implicit gr
ey LTE radiation transport scheme based on the moment equations, a tot
al energy equation for the gas and the radiation field, expansion opac
ities, and a Monte Carlo gamma-ray deposition scheme. To evolve the st
ructure of the underlying explosion models homologous expansion is ass
umed. We find that fast rising light curves (e.g., SN 1972E, SN 1981B
and SN 1986G) can be reproduced best by delayed detonation models, and
that slowly rising (t(max) greater than or similar 17 days) light cur
ves (e.g., SN 1984A and SN 1990N) cannot be reproduced by standard det
onation, deflagration or delayed detonation models. In order to obtain
an acceptable agreement with observations for slowly rising light cur
ves explosion models are required where the C/O white dwarf is surroun
ded by an unburnt extended envelope of typically 0.2 to 0.4 M.. Our in
terpretation of the light curves is also favoured from the expansion v
elocities observed in the spectra of the slowly rising SNIa. Based on
a comparison of theoretical light curves and observational data, the d
istances of the parent galaxies have been determined. We show that SNe
la allow for a measurement of the value of the Hubble constant provid
ed individual fits are used and if they are located at distances large
r than 15 Mpc, because only then they are in the ''Hubble'' flow. Taki
ng this restriction into account a Hubble constant of H = 66 +/- 10 km
/(secMpc) can be derived within a 2sigma error.