Bradley E. Schaefer, Ashley Pagnotta
Type Ia supernova (SNe Ia) are thought to originate in the explosion of a
white dwarf. The explosion could be triggered by the merger of two white dwarfs
('double-degenerate' origin), or by mass transfer from a companion star (the
'single-degenerate' path). The identity of the progenitor is still
controversial; for example, a recent argument against the single-degenerate
origin has been widely rejected. One way to distinguish between the double- and
single-degenerate progenitors is to look at the center of a known SN Ia remnant
to see whether any former companion star is present. A likely ex-companion star
for the progenitor of Tycho's supernova has been identified, but that claim is
still controversial. Here we report that the central region of the supernova
remnant SNR 0509-67.5 (the site of a Type Ia supernova 400+-50 years ago, based
on its light echo) in the Large Magellanic Cloud contains no ex-companion star
to a limit of V=26.9 magnitude (M_V=+8.4) within the extreme 99.73% region with
radius 1.43". The lack of any ex-companion star to deep limits rules out all
published single-degenerate models. The only remaining possibility is that the
progenitor for this particular SN Ia was a double-degenerate system.
View original:
http://arxiv.org/abs/1201.2195
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