论文标题
预测无氢的脉冲配对超新星的射流
Predictions for the hydrogen-free ejecta of pulsational pair-instability supernovae
论文作者
论文摘要
当前的时间域天文学工作将揭示各种罕见的瞬变。我们在这里专注于脉冲配对进化，这可能会导致可观察到电磁和重力波的签名。我们模拟裸氦星的网格，以表征所得的黑洞（BH）质量和射流组成，速度和热状态。恒星不会“弹性”对热核爆炸的反应：配对驱动的点火和质量弹出之间没有一对一的对应关系，从而导致可观察到的脉冲的歧义。与先前的研究一致，我们发现对于碳氧核心质量28msun <m_co <30.5msun爆炸不足以影响表面。随着质量的增加，它们首先引起大径向膨胀（30.5msun <m_co <31.4msun），最后还引起质量弹射发作（M_CO> 31.4msun）。在成对稳定的超新星中完全破坏的最低质量是m_co = 57msun。具有M_CO> 121msun的模型达到了光电散发体制，导致M_BH> 125msun的BHS。如果脉动模型通过（弱）爆炸产生BHS，则先前发射的材料可能会被爆炸波击中。我们从氦气核的脉动配对中表征了无h的室外材料，假设射流后射流保持恒定速度。我们的模型产生质量10^{-3} msun <m_csm <40msun的质量弹射。这些喷射通常以几千kms的速度启动，并在核心折叠之前达到〜10^{12} -10^{15} cm的距离。质量弹出事件和最终崩溃之间的延迟范围范围很广，质量依赖性范围（从小时到10^4年），而被喷出的壳也可能相互碰撞。我们发现的属性范围表明与（某些）IBN超新星类型的连接。
Present time-domain astronomy efforts will unveil a variety of rare transients. We focus here on pulsational pair-instability evolution, which can result in signatures observable with electromagnetic and gravitational waves. We simulate grids of bare helium stars to characterize the resulting black hole (BH) masses and ejecta composition, velocity, and thermal state. The stars do not react "elastically" to the thermonuclear explosion: there is not a one-to-one correspondence between pair-instability driven ignition and mass ejections, causing ambiguity in what is an observable pulse. In agreement with previous studies, we find that for carbon-oxygen core masses 28Msun< M_CO<30.5Msun the explosions are not strong enough to affect the surface. With increasing mass, they first cause large radial expansion (30.5Msun<M_CO<31.4Msun), and finally, also mass ejection episodes (M_CO>31.4Msun). The lowest mass to be fully disrupted in a pair-instability supernova is M_CO=57Msun. Models with M_CO>121Msun reach the photodisintegration regime, resulting in BHs with M_BH>125Msun. If the pulsating models produce BHs via (weak) explosions, the previously-ejected material might be hit by the blast wave. We characterize the H-free circumstellar material from the pulsational pair-instability of helium cores assuming simply that the ejecta maintain a constant velocity after ejection. Our models produce He-rich ejecta with mass 10^{-3}Msun<M_CSM<40Msun. These ejecta are typically launched at a few thousand \kms and reach distances of ~10^{12}-10^{15} cm before core-collapse. The delays between mass ejection events and the final collapse span a wide and mass-dependent range (from sub-hour to 10^4 years), and the shells ejected can also collide with each other. The range of properties we find suggests a possible connection with (some) type Ibn supernovae.
