A strange star scenario for the formation of eccentric millisecond pulsar PSR J1946+3417  

作　　者：Long Jiang Na Wang Wen-Cong Chen Wei-Min Liu Chun-Wei Leng Jian-Ping Yuan Xiang-Li Qian 

机构地区：[1]Xinjiang Astronomical Observatory,Chinese Academy of Sciences,Urumqi 830011,China [2]School of Science,Qingdao University of Technology,Qingdao 266525,China [3]School of Physics and Electrical Information,Shangqiu Normal University,Shangqiu 476000,China [4]Department of Intelligent Engineering,Shandong Management University,Jinan 250357,China

出　　处：《Research in Astronomy and Astrophysics》2021年第9期185-192,共8页天文和天体物理学研究（英文版）

基　　金：supported by the CAS‘Light of West China’Program(Grant No.2018-XBQNXZ-B-022);the National Natural Science Foundation of China(Grant Nos.11803018,11733009,11773015,U2031116 and 11605110);the National Key Research and Development Program of China(Grant No.2016YFA0400803);the Program for Innovative Research Team(in Science and Technology)at the University of Henan Province;the Key laboratory of Modern Astronomy and Astrophysics(Nanjing University),Ministry of Education。

摘　　要：PSR J1946+3417 is a millisecond pulsar(MSP)with a spin period P?3.17 ms.Harbored in a binary with an orbital period Pb?27 days,the MSP is accompanied by a white dwarf(WD).The masses of the MSP and the WD were determined to be 1.83 M⊙,and 0.266 M⊙,respectively.Specially,its orbital eccentricity is e?0.134,which is challenging the recycling model of MSPs.Assuming that the neutron star in a binary may collapse to a strange star when its mass reaches a critical limit,we propose a phase transition(PT)scenario to account for the origin of the system.The sudden mass loss and the kick induced by asymmetric collapse during the PT may result in the orbital eccentricity.If the PT event takes place after the mass transfer ceases,the eccentric orbit cannot be re-circularized in the Hubble time.Aiming at the masses of both components,we simulate the evolution of the progenitor of PSR J1946+3417 via MESA.The simulations show that an NS/main sequence star binary with initial masses of 1.4+1.6 M⊙in an initial orbit of 2.59 days will evolve into a binary consisting of a 2.0 M⊙MSP and a 0.27 M⊙WD in an orbit of~21.5 days.Assuming that the gravitational mass loss fraction during PT is 10%,we simulate the effect of PT via the kick program of BSE with a velocity ofσPT=60 km s-1.The results show that the PT scenario can reproduce the observed orbital period and eccentricity with higher probability than other values.

关 键 词：stars:neutron stars:evolution pulsars:individual(J1946+3417) 

分 类 号：P145.6[天文地球—天体物理]