Shock‐heating of stellar envelopes: a possible common mechanism at the origin of explosions and eruptions in massive stars
Shock‐heating of stellar envelopes: a possible common mechanism at the origin of explosions and eruptions in massive stars
复制标题
恒星包层的激波加热：大质量恒星爆炸和喷发起源的可能常见机制
DOI：
10.1111/j.1365-2966.2010.16626.x
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发表时间：
2009
影响因子：
4.8
通讯作者：
R. Waldman
中科院分区：
文献类型：
--
作者：
L. Dessart;E. Livne;R. Waldman
Observations of transient phenomena in the Universe reveal a spectrum of mass-ejection properties associated with massive stars, covering from Type II/Ib/Ic core-collapse supernovae (SNe) to giant eruptions of luminous blue variables (LBV) and optical transients. In this work, we hypothesize that a large fraction of these phenomena may have an explosive origin, the distinguishing ingredient being the ratio of the prompt energy release E dep to the envelope binding energy E binding . Using one-dimensional one-group radiation hydrodynamics and a set of 10-25 M massive-star models, we explore the dynamical response of a stellar envelope subject to a strong, sudden and deeply rooted energy release. Following energy deposition, a shock systematically forms, crosses the progenitor envelope on a time-scale of a day and breaks out with a signal of a duration of hours to days and a 10 5 ―10 11 L luminosity. We identify three different regimes, corresponding to a transition from dynamic to quasi-static diffusion transport. For E dep > E binding , full envelope ejection results with an SN-like bolometric luminosity and kinetic energy, modulations being commensurate to the energy deposited and echoing the diversity of Type II-Plateau SNe. For E dep ∼ E binding , partial envelope ejection results with a small expansion speed and a more modest but year-long luminosity plateau, reminiscent of LBV eruptions or so-called SN impostors. For E de p < E binding , we obtain a 'puffed-up' star, secularly relaxing back to thermal equilibrium. In parallel with gravitational collapse and Type II SNe, we argue that thermonuclear combustion, for example of as little as a few 0.01 M of C/O, could power a wide range of explosions/eruptions. Besides massive stars close to the Eddington limit and/or critical rotation, 8-12 M red supergiants, which are amongst the least bound of all stars, represent attractive candidates for transient phenomena.
