The missing compact star of SN1987A: a solid quark star?

Abstract

To investigate the missing compact star of Supernova 1987A, we analyzed both the cooling and the heating processes of a possible compact star based on the upper limit of observational X-ray luminosity. From the cooling process we found that a solid quark-cluster star, which has a stiffer equation of state than that of conventional liquid quark star, has a heat capacity much smaller than a neutron star. It can cool down quickly, which can naturally explain the non-detection of a point source (neutron star or quark star) in X-ray band. On the other hand, we consider the heating process from magnetospheric activity and possible accretion, and obtain some constraints to the parameters of a possible pulsar. We conclude that a solid quark-cluster star can be fine with the observational limit in a large and acceptable parameter space. A pulsar with a short period and a strong magnetic field (or with a long period and a weak field) would has luminosity higher than the luminosity limit if the optical depth is not large enough to hide the compact star. The constraints of the pulsar parameters can be tested if the central compact object in 1987A is discovered by advanced facilities in the future.Comment: 5 pages, 2 figures (submitted to MNRAS

A Strange Star Scenario for the Formation of Eccentric Millisecond Pulsar/Helium White Dwarf Binaries

“…Considering that the strange quark matter is most stable, the concept of SS was proposed (Itoh 1970;Bodmer 1971;Farhi & Jaffe 1984;Witten 1984;Alcock et al 1986;Haensel et al 1986;Xu 2003;Lai & Xu 2009;Liu et al 2012), i. e. some pulsars may be SSs instead of NSs. Believing that both NSs and SSs coexist in the Universe, it was argued that NS-SS PT may occur when the central density of an NS rises above the quark de-confinement density (Berezhiani et al 2003;Bombaci 2004;Bombaci et al 2008;Zhu et al 2013;Bombaci et al 2016;Drago et al 2016;Bhattacharyya et al 2017;Wiktorowicz et al 2017;Hou et al 2018;Alvarez-Castillo et al 2019).…”

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

“…Considering that the strange quark matter is most stable, the concept of SS was proposed (Itoh 1970;Bodmer 1971;Farhi & Jaffe 1984;Witten 1984;Alcock et al 1986;Haensel et al 1986;Xu 2003;Lai & Xu 2009;Liu et al 2012), i.e., some pulsars may be SSs instead of NSs. Believing that both NSs and SSs coexist in the Universe, it was argued that NS-SS PT may occur when the central density of an NS rises above the quark de-confinement density (Berezhiani et al 2003;Bombaci et al 2004Bombaci et al , 2008Zhu et al 2013;Bombaci et al 2016;Drago et al 2016;Bhattacharyya et al 2017;Wiktorowicz et al 2017;Hou et al 2018;Alvarez-Castillo et al 2019).…”