beecee Posted June 8, 2021 Posted June 8, 2021 https://phys.org/news/2021-06-source-gw190814-event-black-hole-strange.html JUNE 8, 2021 Could the source of the GW190814 event be a black hole-strange quark star system? On the 14th of August 2019, the LIGO-Virgo collaboration detected a gravitational wave signal believed to be associated with the merging of a binary stellar system composed of a black hole with a mass of 23 times the mass of the sun (M⊙) and a compact object with a mass of about 2.6 M⊙. The nature of GW190814ʼs secondary star is enigmatic, since, according to the current astronomical observations, it could be the heaviest neutron star or the lightest black hole ever observed. Researchers at University of Pisa, University of Ferrara and the National Institute for Nuclear Physics (INFN) in Italy have recently carried out a study exploring the possibility that the source of the GW190814 event detected by LIGO-Virgo is a black hole-strange quark star system. Their paper, published in Physical Review Letters, is based on an astrophysical model that they developed several years ago. more at link........... the paper: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.162702 Was GW190814 a Black Hole–Strange Quark Star System? Abstract: We investigate the possibility that the low mass companion of the black hole in the source of GW190814 was a strange quark star. This possibility is viable within the so-called two-families scenario in which neutron stars and strange quark stars coexist. Strange quark stars can reach the mass range indicated by GW190814, M∼(2.5–2.67) M⊙ due to a large value of the adiabatic index, without the need for a velocity of sound close to the causal limit. Neutron stars (actually hyperonic stars in the two-families scenario) can instead fulfill the presently available astrophysical and nuclear physics constraints which require a softer equation of state. In this scheme it is possible to satisfy both the request of very large stellar masses and of small radii while using totally realistic and physically motivated equations of state. Moreover it is possible to get a radius for a 1.4 M⊙ star of the order or less than 11 km, which is impossible if only one family of compact stars exists.
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