HEAD-ON COLLISIONS OF WHITE DWARFS IN TRIPLE SYSTEMS COULD EXPLAIN TYPE Ia SUPERNOVAE

Journal Article · Sun Dec 01 00:00:00 EST 2013 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/778/2/L37· OSTI ID:22364107

Kushnir, Doron; Katz, Boaz; Dong, Subo; Fernández, Rodrigo ^[1]; Livne, Eli ^[2]

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1. Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)
2. Racah Institute of Physics, Hebrew University, Jerusalem (Israel)

Type Ia supernovae (SNe Ia), thermonuclear explosions of carbon-oxygen white dwarfs (CO-WDs), are currently the best cosmological ''standard candles'', but the triggering mechanism of the explosion is unknown. It was recently shown that the rate of head-on collisions of typical field CO-WDs in triple systems may be comparable to the SNe Ia rate. Here we provide evidence supporting a scenario in which the majority of SNe Ia are the result of such head-on collisions of CO-WDs. In this case, the nuclear detonation is due to a well understood shock ignition, devoid of commonly introduced free parameters such as the deflagration velocity or transition to detonation criteria. By using two-dimensional hydrodynamical simulations with a fully resolved ignition process, we show that zero-impact-parameter collisions of typical CO-WDs with masses 0.5-1 M {sub ☉} result in explosions that synthesize {sup 56}Ni masses in the range of ∼0.1-1 M {sub ☉}, spanning the wide distribution of yields observed for the majority of SNe Ia. All collision models yield the same late-time (≳ 60 days since explosion) bolometric light curve when normalized by {sup 56}Ni masses (to better than 30%), in agreement with observations. The calculated widths of the {sup 56}Ni-mass-weighted line-of-sight velocity distributions are correlated with the calculated {sup 56}Ni yield, agreeing with the observed correlation. The strong correlation, shown here for the first time, between {sup 56}Ni yield and total mass of the colliding CO-WDs (insensitive to their mass ratio), is suggestive as the source for the continuous distribution of observed SN Ia features, possibly including the Philips relation.

• OSTI ID: 22364107
• Journal Information: Astrophysical Journal Letters, Vol. 778, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ASTROPHYSICS
BOLOMETERS
CARBON
CARBON MONOXIDE
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
CORRELATIONS
COSMOLOGY
DIAGRAMS
HYDRODYNAMICS
IMPACT PARAMETER
NICKEL 56
NUCLEOSYNTHESIS
OXYGEN
SUPERNOVAE
THERMONUCLEAR EXPLOSIONS
TWO-DIMENSIONAL CALCULATIONS
VISIBLE RADIATION
WHITE DWARF STARS