Evolutionary Paths to Type Ia Supernovae

我们提出了新的演化模型Ia型超新星（SN Ia）的祖先，引入质量剥离效应的主序星（MS）或轻微演变的同伴星星的风从质量吸积白色矮星（WD）。质量汽提减弱了从同伴到WD的质量传递速率。因此，一个非常大质量的MS伴星可以避免形成一个共同的包层，从而可以增加WD的质量，直到超新星Ia爆炸。在考虑质量剥离效应的情况下，我们跟踪了不同WD + MS系统的双星演化，得到了Ia型超新星在初始施主质量-轨道周期平面上的参数区域。新获得的超新星Ia区延伸到6-7 Msolar的施主质量，尽管其延伸取决于质量剥离效应的效率。被剥离的物质主要分布在轨道平面上，并在SN Ia祖星周围形成非常大质量的星周物质（CSM）。这可以解释Ia/Iin型超新星SN 2002 ic和SN 2005 gj周围的大质量CSM，以及正常Ia型超新星SN 2006 X周围的稀薄CSM。我们的新模型表明，存在非常年轻（<10^8年）的Sne Ia种群，这与最近观察到的Sne Ia种群数量非常少的迹象一致。

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.