Could there be a hole in type Ia supernovae?
In the favored progenitor scenario, Type Ia supernovae (SNe Ia) arise from a white dwarf accreting material from a non-degenerate companion star. Soon after the white dwarf explodes, the ejected supernova material engulfs the companion star; two-dimensional hydrodynamical simulations by Marietta et al. (2001) show that, in the interaction, the companion star carves out a conical hole of opening angle 30-40 degrees in the supernova ejecta. In this paper we use multi-dimensional Monte Carlo radiative transfer calculations to explore the observable consequences of an ejecta-hole asymmetry. We calculate the variation of the spectrum, luminosity, and polarization with viewing angle for the aspherical supernova near maximum light. We find that the supernova looks normal from almost all viewing angles except when one looks almost directly down the hole. In the latter case, one sees into the deeper, hotter layers of ejecta. The supernova is relatively brighter and has a peculiar spectrum characterized by more highly ionized species, weaker absorption features, and lower absorption velocities. The spectrum viewed down the hole is comparable to the class of SN 1991T-like supernovae. We consider how the ejecta-hole asymmetry may explain the current spectropolarimetric observations of SNe Ia, and suggest a few observational signatures of the geometry. Finally, we discuss the variety currently seen in observed SNe Ia and how an ejecta-hole asymmetry may fit in as one of several possible sources of diversity.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director. Office of Science. Office of Advanced Scientific Computing Research; Nation Aeronautics and Space Administration (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 836970
- Report Number(s):
- LBNL-54943; R&D Project: KX0410; TRN: US0500853
- Journal Information:
- Astrophysical Journal, Vol. 610, Issue 2 pt1; Other Information: Submitted to Astrophysical Journal: Volume 610, No.2 part 1; Journal Publication Date: 08/01/2004; PBD: 23 Apr 2004
- Country of Publication:
- United States
- Language:
- English
Similar Records
Type Ia Supernovae From Merging White Dwarfs. II. Post-Merger Detonations
Type Ia supernovae from merging white dwarfs. I. Prompt detonations
Related Subjects
GENERAL PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ABSORPTION
ASYMMETRY
GEOMETRY
LUMINOSITY
OPENINGS
POLARIZATION
RADIANT HEAT TRANSFER
STARS
SUPERNOVAE
THERMONUCLEAR SUPERNOVAE 3-D RADIATIVE TRANSFER SPECTRUM SYNTHESIS