一个天生的超大质量白矮星——热亚矮星超钱德拉塞卡候选体
A born ultramassive white dwarf-hot subdwarf super-Chandrasekhar candidate
AI总结：
本文发现双星Lan 11中存在一颗天生的超大质量ONe白矮星候选体，系统总质量超钱德拉塞卡极限，预计5亿至5.4亿年后并合并可能触发AIC。
摘要：
尽管超新星是吸积白矮星众所周知的终点，但其他理论可能性也得到广泛讨论，例如以吸积诱发坍缩（AIC）事件作为氧氖（ONe）白矮星的终点，其方式可以是通过吸积达到或通过并合而超过钱德拉塞卡极限（稳定白矮星的最大质量）。AIC是形成中子星的重要渠道，尤其对于那些难以由核心坍缩超新星产生的特殊系统而言。然而，这一理论预言事件及其前身星的观测证据都非常有限。在所有已知前身星中，白矮星都通过吸积增加质量。在此，我们报告发现了一个引人关注的双星系统Lan 11，它由一颗被剥离的核心氦燃烧热亚矮星和一个质量为1.08至1.35倍太阳质量的不可见致密天体组成。我们的双星种群合成计算，加上五百米口径球面射电望远镜深度射电观测未探测到信号，有力表明后者是一颗ONe白矮星。该双星的总质量为1.67至1.92倍太阳质量，显著超过钱德拉塞卡极限。对其演化历史的复现表明，这一独特系统经历了两个阶段的公共包层抛射，意味着这颗大质量ONe白矮星具有天生性质，而非通过来自伴星的吸积增长形成。这些结果连同该双星较短的轨道周期（3.65小时）表明，该系统将在5亿至5.4亿年内并合，极有可能触发AIC事件，尽管仍不能完全排除Ia型超新星的可能性。无论最终导致AIC还是超新星，这一发现都为我们理解恒星终点提供了宝贵约束。
英文摘要：
Although supernovae is a well-known endpoint of an accreting white dwarf, alternative theoretical possibilities has been discussing broadly, such as the accretion-induced collapse (AIC) event as the endpoint of oxygen-neon (ONe) white dwarfs, either accreting up to or merging to excess the Chandrasekhar limit (the maximum mass of a stable white dwarf). AIC is an important channel to form neutron stars, especially for those unusual systems, which are hardly produced by core-collapse supernovae. However, the observational evidences for this theoretical predicted event and its progenitor are all very limited. In all of the known progenitors, white dwarfs increase in mass by accretion. Here, we report the discovery of an intriguing binary system Lan 11, consisted of a stripped core-helium-burning hot subdwarf and an unseen compact object of 1.08 to 1.35 $M_{\odot}$. Our binary population synthesis calculations, along with the absence of detection from the deep radio observations of the Five-hundred-meter Aperture Spherical Radio Telescope, strongly suggest that the latter is an ONe white dwarf. The total mass of this binary is 1.67 to 1.92 $M_{\odot}$}, significantly excessing the Chandrasekhar limit. The reproduction of its evolutionary history indicates that the unique system has undergone two phases of common envelope ejections, implying a born nature of this massive ONe white dwarf rather than an accretion growth from its companion. These results, together with short orbital period of this binary (3.65 hours), suggest that this system will merge in 500-540 Myr, largely triggering an AIC event, although the possibility of type Ia supernova cannot be fully ruled out. This finding greatly provides valuable constraints on our understanding of stellar endpoints, whatever leading to an AIC or a supernova.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
