SIGNATURES OF A COMPANION STAR IN TYPE IA SUPERNOVAE

Although type Ia supernovae (SNe Ia) have been used as precise cosmological distance indicators, their progenitor systems remain unresolved. One of the key questions is whether there is a nondegenerate companion star at the time of a thermonuclear explosion of a white dwarf. In this paper, we invest...

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Bibliographic Details
Published in:The Astrophysical journal 2014-10, Vol.794 (1), p.1-29
Main Authors: Maeda, Keiichi, Kutsuna, Masamichi, Shigeyama, Toshikazu
Format: Article
Language:English
Subjects:
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
BRIGHTNESS
CALIBRATION
COLOR
Companion stars
HYDROGEN
INFRARED SPECTRA
INTERACTIONS
LUMINOSITY
Mathematical models
Progenitors (astrophysics)
RADIANT HEAT TRANSFER
Scatter
Signatures
SIMULATION
Supernovae
THERMONUCLEAR EXPLOSIONS
TYPE I SUPERNOVAE
WHITE DWARF STARS
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Summary:Although type Ia supernovae (SNe Ia) have been used as precise cosmological distance indicators, their progenitor systems remain unresolved. One of the key questions is whether there is a nondegenerate companion star at the time of a thermonuclear explosion of a white dwarf. In this paper, we investigate whether an interaction between the SN ejecta and the companion star may result in observable footprints around the maximum brightness and thereafter, by performing multidimensional radiation transfer simulations based on hydrodynamic simulations of the interaction. We find that such systems result in variations in various observational characteristics due to different viewing directions, and the predicted behaviors (redder and fainter for the companion direction) are the opposite of what were suggested by the previous study. The variations are generally modest and within observed scatters. However, the model predicts trends between some observables different from those observationally derived, so a large sample of SNe Ia with small calibration errors may be used to constrain the existence of such a companion star. The variations in different colors in optical band passes can be mimicked by external extinctions, so such an effect could be a source of scatter in the peak luminosity and derived distance. After the peak, hydrogen-rich materials expelled from the companion will manifest themselves in hydrogen lines, but H alpha is extremely difficult to identify. Alternatively, we find that P beta in postmaximum near-infrared spectra can potentially provide a powerful diagnostic.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/794/1/37