Quark stars are a bit like neutron stars, they have very large masses and small radii. Can we detect gravitational waves emitted in a binary of two quark stars or the gravitational waves from a not perfectly round quark star which is rotating? If it is possible, could LIGO detect it or is it on another frequency? How could the detectors see the difference between quark stars and neutron stars?

  • $\begingroup$ Quark stars are hypothetical in nature, though on the grounds of the question, it could be detected, though I can't say how strong would the gravitational waves be. $\endgroup$
    – Orion 73
    Apr 15, 2020 at 12:07

1 Answer 1


Quark stars, if they exist, would emit gravitational waves in a similar manner as neutron stars. In fact, their gravitational wave signals would be almost identical to that of a pair of merging neutron stars. The different composition of the objects would only express itself in differences in the tidal deformability, which would lead to a small but potentially measurable difference in the gravitational waveform (especially close to merger).

  • $\begingroup$ Why are quark stars are more 'fluid', why do they have a greater tidal deformability then neutron stars? What does that deformability change in the gravitational waves? $\endgroup$
    – BOB
    Apr 15, 2020 at 13:31
  • $\begingroup$ I'm not saying that the tidal deform-ability would be greater, I'm saying it would be different. (Intuitively I would expect quark stars to be harder to deform.) The mutual tidal deform-ability of the stars leads to extra gravitational interactions between the stars. Consequently, the orbit evolves at a different rate, leading the gravitational waves to be slightly out of phase relative to a similar mass neutron star. This same principle is used in LIGO to try to learn about the behaviour of neutron star interiors. $\endgroup$
    – TimRias
    Apr 15, 2020 at 14:09
  • $\begingroup$ And how does LIGO learn about the interiors of the neutron stars? $\endgroup$
    – BOB
    Apr 15, 2020 at 16:32
  • $\begingroup$ Quark stars generally have smaller tidal deformabilitiea as they have "softer" equations of state. In future, we may be able to measure gravitational waves from the postmerger remnant and this will help determine whether the original stars were neutron stars or quark stars. If this is the case then we will know a lot more about the tidal parameters and hence equation of state from the inspiral chirp. $\endgroup$
    – PaulEaster
    Jul 6, 2021 at 13:46

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