标题： 氦壳爆炸作为低质量白矮星可能解释SN 2005E的原因 显示英文标题

标题： Helium Shell Detonations on Low Mass White Dwarfs as a Possible Explanation for SN 2005E

摘要： 最近，几种类型 Ib 超新星（SNe；以典型的 SN 2005E 为代表）已被证明具有非典型特性。这些 SNe 较暗（峰值绝对星等约为 -15），并且是快速的 SNe，表现出独特的组成。它们被推断具有较低的抛射质量（约十分之一个太阳质量），并且富含钙元素，但硅元素和镍含量较少。因此，这些 SNe 被认为属于一种新的钙丰富的暗弱 SNe 爆炸类别。它们的特性被认为是由可能发生在吸积氦的白矮星上的氦爆炸所致。在本文中，我们从理论上研究了氦爆炸的情景，并重点研究了在低质量碳-氧（CO）核心上的吸积氦层中的爆炸结果。我们展示了此类爆炸的一维模拟的新结果，包括它们的光变曲线和光谱。我们发现，当氦层的密度足够低时，氦爆炸会产生大量中间元素，如钙和钛，以及大量未燃烧的氦。我们的结果表明，钙丰富的暗弱 SNe 的特性确实可以与小 CO 核心上的氦爆炸情景一致。在某一密度以上（较大的 CO 核心），爆炸主要留下 56Ni 和未燃烧的氦，预测的光谱不太可能符合这类 SNe 的独特特征。最后，我们研究的所有模型都无法再现另一种被认为起源于氦爆炸的特殊 SNe（SNe 1885A、1939B 和 2002bj）的明亮、快速演化的光变曲线。 显示英文摘要

摘要： Recently several type Ib supernovae (SNe; with the prototypical SN 2005E) have been shown to have atypical properties. These SNe are faint (absolute peak magnitude of ~ -15) and fast SNe that show unique composition. They are inferred to have low ejecta mass (a few tenths of a solar mass) and to be highly enriched in calcium, but poor in silicon elements and nickel. These SNe were therefore suggested to belong to a new class of calcium-rich faint SNe explosions. Their properties were proposed to be the result of helium detonations that may occur on helium accreting white dwarfs. In this paper we theoretically study the scenario of helium detonations, and focus on the results of detonations in accreted helium layers on low mass carbon-oxygen (CO) cores. We present new results from one dimensional simulations of such explosions, including their light curves and spectra. We find that when the density of the helium layer is low enough the helium detonation produces large amounts of intermediate elements, such as calcium and titanium, together with a large amount of unburnt helium. Our results suggest that the properties of calcium-rich faint SNe could indeed be consistent with the helium-detonation scenario on small CO cores. Above a certain density (larger CO cores) the detonation leaves mainly 56Ni and unburnt helium, and the predicted spectrum will unlikely fit the unique features of this class of SNe. Finally, none of our studied models reproduces the bright, fast evolving light curves of another type of peculiar SNe suggested to originate in helium detonations (SNe 1885A, 1939B and 2002bj).