Valenti S, Pastorello A, Cappellaro E, Benetti S, Mazzali P A, Manteca J, Taubenberger S, Elias-Rosa N, Ferrando R, Harutyunyan A, Hentunen V P, Nissinen M, Pian E, Turatto M, Zampieri L, Smartt S J
Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN, UK.
Nature. 2009 Jun 4;459(7247):674-7. doi: 10.1038/nature08023.
The final fate of massive stars depends on many factors. Theory suggests that some with initial masses greater than 25 to 30 solar masses end up as Wolf-Rayet stars, which are deficient in hydrogen in their outer layers because of mass loss through strong stellar winds. The most massive of these stars have cores which may form a black hole and theory predicts that the resulting explosion of some of them produces ejecta of low kinetic energy, a faint optical luminosity and a small mass fraction of radioactive nickel. An alternative origin for low-energy supernovae is the collapse of the oxygen-neon core of a star of 7-9 solar masses. No weak, hydrogen-deficient, core-collapse supernovae have hitherto been seen. Here we report that SN 2008ha is a faint hydrogen-poor supernova. We propose that other similar events have been observed but have been misclassified as peculiar thermonuclear supernovae (sometimes labelled SN 2002cx-like events). This discovery could link these faint supernovae to some long-duration gamma-ray bursts, because extremely faint, hydrogen-stripped core-collapse supernovae have been proposed to produce such long gamma-ray bursts, the afterglows of which do not show evidence of associated supernovae.
大质量恒星的最终命运取决于许多因素。理论表明，一些初始质量大于25至30个太阳质量的恒星最终会成为沃尔夫-拉叶星，由于通过强烈的恒星风造成质量损失，它们的外层氢元素匮乏。这些恒星中质量最大的恒星具有可能形成黑洞的核心，并且理论预测其中一些恒星最终的爆炸会产生低动能的抛射物、微弱的光学光度以及少量的放射性镍。低能量超新星的另一个起源是质量为7至9个太阳质量的恒星的氧氖核心坍缩。迄今为止尚未观测到弱的、贫氢的核心坍缩超新星。在此我们报告，超新星2008ha是一颗微弱的贫氢超新星。我们提出，其他类似事件已被观测到，但被错误地归类为特殊热核超新星（有时被标记为类超新星2002cx事件）。这一发现可能将这些微弱的超新星与一些长持续时间的伽马射线暴联系起来，因为有人提出极其微弱的、氢被剥离的核心坍缩超新星会产生这样的长伽马射线暴，其余晖并未显示出相关超新星的迹象。
