SN 2008D: A WOLF-RAYET EXPLOSION THROUGH A THICK WIND

作者：Svirski Gilad^*; Nakar Ehud

来源：Astrophysical Journal Letters, 2014, 788(1): L14.

DOI：10.1088/2041-8205/788/1/L14

• radiation mechanisms: non-thermal
• stars: mass-loss
• stars: Wolf-Rayet
• supernovae: general
• supernovae: individual (2008D)
• X-rays: bursts

Supernova (SN) 2008D/XRT 080109 is considered to be the only direct detection of a shock breakout from a regular SN to date. While a breakout interpretation was favored by several papers, inconsistencies remain between the observations and current SN shock breakout theory. Most notably, the duration of the luminous X-ray pulse is considerably longer than expected for a spherical breakout through the surface of a type Ibc SN progenitor, and the X-ray radiation features, mainly its flat spectrum and its luminosity evolution, are enigmatic. We apply a recently developed theoretical model for the observed radiation from a Wolf-Rayet SN exploding through a thick wind and show that it naturally explains all of the observed features of SN 2008D X-ray emission, including the energetics, the spectrum, and the detailed luminosity evolution. We find that the inferred progenitor and SN parameters are typical for an exploding Wolf-Rayet. A comparison of the wind density found at the breakout radius and the density at much larger radii, as inferred by late radio observations, suggests an enhanced mass-loss rate taking effect about 10 days prior to the SN explosion. This finding joins accumulating evidence for a possible late phase in the stellar evolution of massive stars, involving vigorous mass loss a short time before the SN explosion.

• 出版日期2014-6-10