On the nature and detectability of Type Ib/c supernova progenitors
On the nature and detectability of Type Ib/c supernova progenitors
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DOI：
10.1051/0004-6361/201219790
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发表时间：
2012-07
影响因子：
6.5
通讯作者：
Sung-Chul Yoon;G. Gräfener;J. Vink;A. Kozyreva;R. Izzard
中科院分区：
文献类型：
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作者：
Sung-Chul Yoon;G. Gräfener;J. Vink;A. Kozyreva;R. Izzard
上下文。许多II型超新星的祖先已经被观测到，但是寻找Ibc型超新星（SN Ibc）的祖先到目前为止还没有成功，尽管它们被期望是发光的沃尔夫-拉叶星（WR）。目标。我们研究了大质量氦恒星的演化如何影响它们的视觉外观，并讨论了SN Ibc祖恒星的可探测性。方法。分析了大质量氦恒星的演化模型，并与银河系WR恒星进行了比较。结果。大质量WR恒星通过恒星风的质量损失迅速失去氦包层，当它们的有效温度（与它们的流体静力表面相关）超过大约150 kK时，它们的生命就会结束。在前超新星阶段，它们的表面性质类似于WO亚型的银河系WR热恒星。尽管它们的辐射光度（logL/L = 5.6··5.7）比银河系WR恒星的大部分（Mv < - 4）高，但它们在视觉上是微弱的，窄带视星等为Mv = - 1.5···- 2.5。相比之下，相对低质量的氦恒星保留了厚厚的氦包层，在光学波段上显得相当明亮，这取决于最终质量和演化后期的包层膨胀历史。结论。我们的结论是，到目前为止，即使是最深入的搜索，SNe Ibc的观测也没有提供对其前身的辐射光度和质量的强有力的限制。我们还认为，在任何光学图像中，Ic祖细胞比Ib祖细胞更具有挑战性。
Context. The progenitors of many Type II supernovae have been observationally identified but the search for Type Ibc supernova (SN Ibc) progenitors has thus far been unsuccessful, despite the expectation that they are luminous Wolf-Rayet (WR) stars. Aims. We investigate how the evolution of massive helium stars affects their visual appearances, and discuss the implications for the detectability of SN Ibc progenitors. Methods. Evolutionary models of massive helium stars are analysed and their properties compared to Galactic WR stars. Results. Massive WR stars that rapidly lose their helium envelopes through stellar-wind mass-loss end their lives when their effective temperatures – related to their hydrostatic surfaces – exceed about 150 kK. At their pre-supernova stage, their surface properties resemble those of hot Galactic WR stars of WO sub-type. These are visually faint with narrow-band visual magnitudes Mv = −1.5 ··· −2.5, despite their high bolometric luminosities (logL/L� = 5.6 ··· 5.7), compared to the bulk of Galactic WR stars (Mv < −4). In contrast, relatively low-mass helium stars that retain a thick helium envelope appear fairly bright in optical bands, depending on the final masses and the history of the envelope expansion during the late evolutionary stages. Conclusions. We conclude that SNe Ibc observations have so far not provided strong constraints on progenitor bolometric luminosities and masses, even with the deepest searches. We also argue that Ic progenitors are more challenging to identify than Ib progenitors in any optical images.