Original title of
: will collisions of neutron stars produce black holes?
in principle it is easy to create a black hole of stellar mass. Just wait for a big star to reach the end of its lifetime watch its core collapse under its own weight. If the mass of the core is greater than 2-3 suns it will become a black hole. Less than about 2.2 solar mass it will become a neutron star. Less than 1.4 solar mass it becomes a white dwarf. The collision of
neutron stars may also form black holes. If they are combined into an object that exceeds the critical limit a black hole should be created. But what exactly is that restriction? A new study in Physical Review Letters tries to answer this question. The team conducted several computer simulations of neutron star merging found that the critical limit is not only related to the total mass of the two stars. Instead the result depends on the internal structure of the neutron star which we still don’t fully underst. Examples of
quark cores are found in neutron stars. Image source: the interior of the neutron star
at CSC’s Jyrki Hokkanen – it science technology center depends on the equation of state of nuclear matter which describes things such as the hardness of matter its ability to conduct heat. There are several proposed EOS each with slightly different properties so the team simulated the merge using a series of EOS.
they found that if the interior of a neutron star is relatively elastic or “soft” even the merging of small neutron stars will produce black holes. But if the interior is hard they don’t collapse into black holes. Instead they will produce a giant fast spinning neutron star that can withst gravitational collapse. A key factor in determining the result is whether the nucleon splits into quarks during the collision.
LIGO Virgo discovered neutron star merging. Photo source: LIGO Virgo / Frank elavsky / Northwestern University
this study may prove crucial to our understing of neutron stars black holes. In 2017 the gravitational wave observatory LIGO Virgo discovered a merger of two neutron stars although they could not tell whether the result was a black hole or a large medium-sized satellite. Over time more mergers should be seen we should be able to identify the key constraints for creating black holes. Combined with this new work we should be able to determine which equation of state best describes the interior of a neutron star.
(Reference: Andreas bauwein et al. “Equation of state constraints from the threshold binary mass for prompt collapse of neutron star mergers.” Physical Review Letters 125.14 (2020): 141103.) return to Sohu to see more