标题： 超新星1994D及未来Ia型超新星的寄主星周H-α辐射：对前身星模型的观测检验 显示英文标题

标题： Circumstellar H-alpha from SN 1994D and future Type Ia supernovae: an observational test of progenitor models

摘要： 搜寻吸积盘物质的存在目前是区分Ia型超新星不同前身星系统的唯一直接方法。 因此，我们在Ia型超新星1994D的一次高分辨率光谱中寻找窄波段的H-α发射线，这次观测是在超新星达到亮度峰值前10天和爆炸后仅6.5天进行的。 我们得出未分辨发射线在局地H II区速度处的上限为 2.0E-16 erg cm^{-2} s^{-1}。 为了估算这个限制对风密度的影响，我们进行了时变光致电离计算。 假设球对称性，我们发现质量损失率的上限大约为对于10 km s^{-1}的风速，每年约为1.5E-5个太阳质量。 这一限制只能排除最高质量损失率的共生系统作为前身星。 我们讨论了不对称性的影响，并评估了早期光学、射电和X射线限制在约束Ia型超新星前身星质量损失方面的相对优势。 我们发现X射线观测可能提供有关前身星质量损失最有效的限制，而高分辨率光学光谱学是我们实际识别吸积盘氢的唯一机会。 显示英文摘要

摘要： Searching for the presence of circumstellar material is currently the only direct way to discriminate between the different types of possible progenitor systems for Type Ia supernovae. We have therefore looked for narrow H-alpha in a high-resolution spectrum of the normal Type Ia supernova 1994D taken 10 days before maximum and only 6.5 days after explosion. We derive an upper limit of 2.0E-16 erg cm^{-2} s^{-1} for an unresolved emission line at the local H II region velocity. To estimate the limit this puts on wind density, we have made time-dependent photoionization calculations. Assuming spherical symmetry we find an upper limit of the mass loss rate which is roughly 1.5E-5 solar masses per year for a wind speed of 10 km s^{-1}. This limit can exclude only the highest-mass-loss-rate symbiotic systems as progenitors. We discuss the effect of asymmetry and assess the relative merits of early optical, radio and X-ray limits in constraining mass loss from Type Ia progenitors. We find that X-ray observations can probably provide the most useful limits on the progenitor mass loss, while high-resolution optical spectroscopy offers our only chance of actually identifying circumstellar hydrogen.