The equation of state of dense matter: Stiff, soft, or both?

Drago, A.; Moretti, M.; Pagliara, Giuseppe

doi:10.1002/asna.201913586

Cited by 15 publications

(16 citation statements)

References 39 publications

(49 reference statements)

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“…The above rather incomplete discussion points to an intrinsic tension for the equations of state of dense matter that need to be both stiff and soft [95]. On the other hand, for P-stars there are no problems since, as shown in Fig.…”

Section: Gw170817mentioning

confidence: 99%

P-stars in the gravitational wave era

Cea

2020

Preprint

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P-stars are compact relativistic stars made of deconfined up and down quarks in a chromomagnetic condensate proposed by us long time ago. P-stars do not admit a critical mass thereby they are able to overcome the gravitational collapse to black holes. In this work we discuss in greater details our theoretical proposal for Pstars. We point out that our theory for compact relativistic stars stems from our own understanding of the confining quantum vacuum supported by estensive nonperturbative numerical simulations of Quantum ChromoDynamics on the lattice. We compare our proposal with the constraints arising from the recent observations of massive pulsars, the gravitational event GW170817 and the precise determination of the PSR J0030+0451 mass and radius from NICER data. We argue that corecollapsed supernovae could give rise to a P-star instead of a neutron star. In this case we show that the birth of a P-star could solve the supernova explosion problem leading to successful supernova explosions with total energies up to 10 53 erg. We critically compare P-stars with the gravitational wave event GW170817 and the subsequent electromagnetic follow-up, the short Gamma Ray Burst GRB170817A and the kilonova AT2017gfo. We also present an explorative study on gravitational wave emission from coalescing binary P-stars with masses M 1 ≃ M 2 ≃ 30 M ⊙ . We attempt a qualitative comparison with the gravitational wave event GW150914. We find that the gravitational wave strain amplitude from massive P-star binaries could mimic the ringdown gravitational wave emission by coalescing black hole binaries. We point out that a clear signature for massive P-stars would be the detection of wobble frequencies in the gravitational wave strain amplitude in the post-merger phase of two coalescing massive compact objects with unequal masses.

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Section: Gw170817mentioning

confidence: 99%

P-stars in the gravitational wave era

Cea

2020

Preprint

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“…In particular, when adopting the most simple prescription i.e. the constant speed of sound (CSS) EoS p = c 2 s (e − e 0 ) where p and e are pressure and energy density [23][24][25][26] 2 one can show that the maximum mass m max ∝ e −1/2 0 [28]. Unfortunately, there is no such a simple scaling with c s .…”

Section: Introductionmentioning

confidence: 99%

Speed of sound in dense matter and two families of compact stars

Traversi,

Char,

Pagliara

et al. 2021

Preprint

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We investigate the possibility of having massive compact stars, (M > 2M ), and at the same time fulfilling the theoretical bounds on the speed of sound cs in dense matter suggesting that the conformal limit of c 2 s = 1/3 is approached from below as the density increases. This is possible if two families of stars exist: hadronic stars and quark stars, the latter being entirely composed by quark matter. By using astrophysical data on electromagnetic and gravitational waves signals of a few sources interpreted as quark stars, we show, within a Bayesian analysis framework, that the posterior distribution of c 2 s is peaked around 0.3, and the maximum mass of the most probable equation of state is ∼ 2.13M . We finally discuss also the possibility that the maximum mass is larger than 2.6M as it could be the case if the secondary component of GW190814 is a compact star and not a black hole.

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“…This kind of process is endothermic and it requires an amount of energy equal at least to the binding (or ionization) energy I. In the following we concentrate on I in the range (50 − 70)MeV, since these values correspond to the ones needed to stabilize QSs up to about 2 M [22]. A first estimate of the evaporation rate stems from the detailed balance principle and it reads [4]:…”

mentioning

confidence: 99%

“…The most basic mechanism to re-heat the strangelet is based on neutrinos: T s is determined by an equilibrium condition between the energy lost by the strangelet, both because of the evaporation and of the neutrino emission, and the energy provided to the strangelet by the neutrino absorption (see eqs. (15,22)…”

mentioning

confidence: 99%

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Formation and evaporation of strangelets during the merger of two compact stars

Bucciantini¹,

Drago²,

Pagliara³

et al. 2019

Preprint

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We study the partial fragmentation of a strange quark star into strangelets during the process of the merger of two strange quark stars or of a strange quark star with a neutron star. We discuss the fate of the fragments considering their possible evaporation into nucleons. We show that only the small amount of large size strangelets produced by tidal forces can survive evaporation, while the strangelets formed during and after the merger evaporate completely into nucleons. In this way we show that: 1) the density of strangelets in the galaxy is too low to be able to affect significantly the evolution of stars and the probability of direct detection of a strangelet is negligible; 2) the matter ejected by the strange quark star during and after the merger evaporates into nucleons and therefore can contribute to the kilonova signal.

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The equation of state of dense matter: Stiff, soft, or both?

Cited by 15 publications

References 39 publications

P-stars in the gravitational wave era

P-stars in the gravitational wave era

Speed of sound in dense matter and two families of compact stars

Formation and evaporation of strangelets during the merger of two compact stars

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