Evolutionary Paths to Type Ia Supernovae

我们提出了Ia型超新星（SN Ia）祖先的新演化模型，引入了质量吸积白矮星（WD）的风对主序星（MS）或轻微演化伴星的质量剥离效应。质量剥离降低了伴体到钻杆的传质速率。因此，一个非常大质量的伴星可以避免形成一个共同的包络层，从而可以增加WD质量，直到SN Ia爆炸。考虑质量剥离效应，我们跟踪了不同WD + MS体系的二元演化，得到了发生Ia型超新星的初始供体质量-轨道周期平面内的参数区域。新获得的SN - Ia区域延伸到6- 7msolar的施主质量，尽管其延伸取决于质量剥离效应的效率。剥离物质主要分布在轨道平面上，并在Ia超新星周围形成非常大质量的星周物质（CSM）。这可以解释Ia/Iin（Iia）型超新星SN 2002ic和SN 2005gj周围的巨大CSM，以及正常Ia型超新星SN 2006X周围的纤细CSM。我们的新模型表明存在非常年轻（< ~ 10^8年）的Ia新星种群，这与最近观测到的Ia新星年轻种群的迹象一致。

We present new evolutionary models for Type Ia supernova (SN Ia) progenitors, introducing the mass-stripping effect on a main-sequence (MS) or slightly evolved companion star by winds from a mass-accreting white dwarf (WD). The mass stripping attenuates the rate of mass transfer from the companion to the WD. As a result, a very massive MS companion can avoid forming a common envelope and thus can increase the WD mass up until the SN Ia explosion. Including the mass-stripping effect, we follow binary evolutions of various WD + MS systems and obtain the parameter region in the initial donor mass-orbital period plane in which SNe Ia occur. The newly obtained SN Ia region extends to donor masses of 6-7 Msolar, although its extension depends on the efficiency of the mass-stripping effect. The stripped matter would mainly be distributed on the orbital plane and would form very massive circumstellar matter (CSM) around the SN Ia progenitor. This can explain the massive CSM around the Type Ia/Iin(Iia) supernovae SN 2002ic and SN 2005gj, as well as the tenuous CSM around the normal Type Ia supernova SN 2006X. Our new model suggests the presence of very young(<〜10^8 yr) populations of Sne Ia, which is consistent with recent observational indications of young-population Sne Ia.