Is the X-ray pulsating companion of HD 49798 a possible type Ia supernova progenitor?  

作　　者：Dong-Dong Liu Wei-Hong Zhou Cheng-Yuan Wu Bo Wang 

机构地区：[1]Yunnan Observatories, Chinese Academy of Sciences [2]Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences [3]University of Chinese Academy of Sciences [4]National Astronomical Observatories, Chinese Academy of Sciences [5]Yunnan Minzu University

出　　处：《Research in Astronomy and Astrophysics》2015年第11期1813-1822,共10页天文和天体物理学研究（英文版）

基　　金：supported by the National Basic Research Program of China (973 program, 2014CB845700);the National Natural Science Foundation of China (Grant Nos. 11322327, 11390374 and 61561053);the Natural Science Foundation of Yunnan Province (Grant Nos. 2013FB083 and 2013HB097)

摘　　要：HD 49798（a hydrogen depleted subdwarf O6 star） with its massive white dwarf（WD） companion has been suggested to be a progenitor candidate of a type Ia supernova（SN Ia）. However, it is still uncertain whether the companion of HD 49798 is a carbon-oxygen（CO） WD or an oxygen-neon（ONe） WD. A CO WD will explode as an SN Ia when its mass grows and approaches the Chandrasekhar limit, but the outcome of an accreting ONe WD is likely to be a neutron star. We generated a series of Monte Carlo calculations that incorperate binary population synthesis to simulate the formation of ONe WD ＋ He star systems. We found that there is almost no orbital period as large as HD 49798 with its WD companion in these ONe WD ＋ He star systems based on our simulations, which means that the companion of HD 49798 might not be an ONe WD. We suggest that the companion of HD 49798 is most likely a CO WD, which can be expected to increase its mass to the Chandrasekhar limit by accreting He-rich material from HD 49798. Thus, HD 49798 and its companion may produce an SN Ia as a result of its future evolution.HD 49798（a hydrogen depleted subdwarf O6 star） with its massive white dwarf（WD） companion has been suggested to be a progenitor candidate of a type Ia supernova（SN Ia）. However, it is still uncertain whether the companion of HD 49798 is a carbon-oxygen（CO） WD or an oxygen-neon（ONe） WD. A CO WD will explode as an SN Ia when its mass grows and approaches the Chandrasekhar limit, but the outcome of an accreting ONe WD is likely to be a neutron star. We generated a series of Monte Carlo calculations that incorperate binary population synthesis to simulate the formation of ONe WD ＋ He star systems. We found that there is almost no orbital period as large as HD 49798 with its WD companion in these ONe WD ＋ He star systems based on our simulations, which means that the companion of HD 49798 might not be an ONe WD. We suggest that the companion of HD 49798 is most likely a CO WD, which can be expected to increase its mass to the Chandrasekhar limit by accreting He-rich material from HD 49798. Thus, HD 49798 and its companion may produce an SN Ia as a result of its future evolution.

关 键 词：progenitor primordial likely uncertain depleted ejection neutron orbital unstable dwarf 

分 类 号：P145.3[天文地球—天体物理] TN78[天文地球—天文学]