A corresponding-state approach to quark-cluster matter

Guo, Y.; Lai, Xiaoyu; Xu, R. X.

doi:10.1088/1674-1137/38/5/055101

Cited by 28 publications

(42 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In order to reduce them, searching for very high mass NSs is an essential method since the maximum mass of NSs determine the stiffness of the EoS. In the case of accretion disc reflection, the derived mass and radius of the NS in 4U 1746-37 could be reproduced in the framework of self-bound NS EoSs, including quark-cluster stars and bare strange stars (Guo et al 2014;Lai et al 2013;Lai & Xu 2009). On the other hand, searching for very low mass NSs is also an attractive way.…”

Section: Discussionmentioning

confidence: 99%

4U 1746–37: An ultra‐low‐mass compact star candidate

2015

Astron Nachr

View full text Add to dashboard Cite

Key words dense matter -equation of state -stars: neutron -X-rays: bursts -X-rays: binaries the Rossi X-ray Timing Explorer observed three photospheric radius expansion bursts in 4U 1746-37, all with low touchdown fluxes. We discuss the possibility of a low-mass neutron star in 4U 1746-37 if the touchdown flux corresponds to its Eddington limit. 4U 1746-37 is a dipping binary system which has a high inclination angle. Two geometric effects, the reflection of the far side accretion disc and the obscuration of the near side accretion disc have also been included. We apply a Monte-Carlo simulation, with typical values of hydrogen mass fraction and color correction factor, to constrain the mass and radius of the neutron star in 4U 1746-37. We found that the mass of 4U 1746-37 is 0.41 +0.70 −0.30 M at 99.7 % confidence which is an ultra-low-mass compact star candidate. It could be reproduced by a self-bound compact star, i.e., quark star or quark-cluster star, from an ccretion-induced collapse process.

show abstract

Section: Discussionmentioning

confidence: 99%

4U 1746–37: An ultra‐low‐mass compact star candidate

2015

Astron Nachr

View full text Add to dashboard Cite

show abstract

“…The hadron star and hybrid/mixed star are gravity bound and covered by crusts with nuclei and electrons, whereas the quark star and The left black lines show the general relativity limit and the central density limit, respectively. Theoretical mass-radius relations for several NS EoS models are displayed, which were introduced by GS1 (Glendenning & Schaffner-Bielich 1999), AP4 (Akmal & Pandharipande 1997), MPA1 (Müther et al 1987), PAL1 (Prakash et al 1988), MS2 (Müller & Serot 1996), GLX123 (Guo et al 2014), and LX12 (Lai & Xu 2009;Lai et al 2013). The purple dot-dashed line represents the bare strange stars obtained from the MIT bag model EoS.…”

Section: Discussionmentioning

confidence: 99%

“…self-bound NS EoSs, including quark-cluster stars and bare strange stars (Lai & Xu 2009;Lai et al 2013;Guo et al 2014). In the case of accretion disk obscuration, the self-bound NSs and gravity-bound NSs (Akmal & Pandharipande 1997;Müther et al 1987) are acceptable in 1σ and 2σ confidence levels of the mass and radius of NSs in 4U 1746-37, respectively.…”

Section: Discussionmentioning

confidence: 99%

An Ultra-Low-Mass and Small-Radius Compact Object in 4u 1746-37?

Chen

et al. 2014

ApJ

View full text Add to dashboard Cite

Photospheric radius expansion (PRE) bursts have already been used to constrain the masses and radii of neutron stars. RXTE observed three PRE bursts in 4U 1746-37, all with low touchdown fluxes. We discuss here the possibility of a low-mass neutron star in 4U 1746-37 because the Eddington luminosity depends on stellar mass. With typical values of hydrogen mass fraction and color correction factor, a Monte Carlo simulation was applied to constrain the mass and radius of a neutron star in 4U 1746-37. 4U 1746-37 has a high inclination angle. Two geometric effects, the reflection of the far-side accretion disk and the obscuration of the near-side accretion disk, have also been included in the mass and radius constraints of 4U 1746-37. If the reflection of the far-side accretion disk is accounted for, a low-mass compact object (mass of 0.41 ± 0.14M and radius of 8.73 ± 1.54 km at 68% confidence) exists in 4U 1746-37. If another effect operated, 4U 1746-37 may contain an ultra-low-mass and small-radius object (M = 0.21 ± 0.06M , R = 6.26 ± 0.99 km at 68% confidence). Combining all possibilities, the mass of 4U 1746-37 is 0.41 +0.70 −0.30 M at 99.7% confidence. For such low-mass neutron stars, it could be reproduced by a self-bound compact star, i.e., a quark star or quark-cluster star.

show abstract

“…It is reasonable that electromagnetic [17,19] non-atomic X-rays Plankian radiation of X-ray very thin atmosphere above surface [10,11] absorption in thermal spectra hydromagnetic oscillation of e − sea [23] strangeness barrier low-z emission, type-I XRB 2-flavored matter separated from 3-f [9] optical/UV excess of XDINS bremsstrahlung radiation [10] global stiff EoS high M max (2 ∼ 3M ⊙ ) non-relativistic strangeon, hard core [3,4,24,25] anisotropic pressure SGR/AXPs burst and flare quake-induced energy release [20,26,27] rigidity precession, GW radiation solid, mountain building [2,28] matter should be separated sharply from strong matter. Bare surface of strangeon star could help in understanding the non-atomic spectra of XDINSs [11].…”

Section: Strangeon Star Identificationmentioning

confidence: 99%

Strangeon Stars

Lu¹,

Xu²

2018

Proceedings of the Workshop on Quarks and Compact Stars 2017 (QCS2017)

View full text Add to dashboard Cite

Stable micro-nucleus is 2-flavored (u and d), whereas stable macro-nucleus could be 3-flavored (u, d and s) if the light flavor symmetry restores there. Nucleons are the constituent of a nucleus, while strangeons are named as the constituent of 3-flavored baryonic matter. Gravity-compressed baryonic object created after core-collapse supernova could be strangeon star if the energy scale (∼ 0.5 GeV) cannot be high enough for quark deconfinement and if there occurs 3-flavor symmetry restoration. Strangeon stars are explained here, including their formation and manifestation/identification. Much work, coupled with effective micro-model of strangeon matter, is needed to take advantage of the unique opportunities advanced facilities will provide. KEYWORDS: pulsar: general, dense matter, equation of stateAlthough the state equation of dense matter around nuclear density is a great challenge for physicists, it is usually a thought that strangeness could be relevant to the solution. As noted in the QC-S2014 proceedings [1], such kind of strange matter is conjectured to be strangeon matter, being manifested in the form of compact stars, cosmic rays, and even dark matter. In this contribution, we are focusing on strangeon star, which is a key ingredient of strangeon matter in astrophysics.It is half a century since the first pulsar was discovered, but the real nature of pulsar remains one of the most puzzling problems both in physics and in astronomy. Pulsars are always thought to be neutron stars, but the issue of their real structure is still controversial. Different observations (e.g., the spin period, the measurements of mass and radius) show that the typical density of pulsar-like compact stars could be only a few nuclear density, and the separation between quarks is ∼ 0.5 fm and hence the energy scale is order of ∼ 0.5 GeV according to Heisenberg's uncertainty relation. The pulsar structure is then a problem of non-perturbative QCD (quantum chromo-dynamics), an unsolved issue for fundamental strong interaction at low energy regime ( 1 GeV). Similar to the issue of turbulence, the strong interaction physics at low-energy is still challenging though QCD is mathematically well-defined. In fact, both of "Navier-Stokes Equation" and "Yang-Mills and Mass Gap" are prize problems named by the Clay Mathematical Institute. Hitherto now, no one can derive pulsar structure from ab-initio calculations, nonetheless astrophysicists could speculate phenomenologically.In Fig. 1, we summarize pulsar inner structures (i.e., models) speculators suggest. All of the pulsar structure models fell into four categories: hadron star, quark star, hybrid/mixed star and strangeon star, as are shown in Fig. 1. In the hadron star model, quarks are confined in hadrons, and the hadron liquid is the dominated part of the star. Hadron stars are bounded by gravity, and they must have crusts composed of ions and electrons. A hadron star is called a neutron star if only the nucleon (proton and neutron) degree of freedom is introduced. Conversely, a quark...

show abstract

A corresponding-state approach to quark-cluster matter

Abstract: A corresponding-state approach to quark-cluster matter * GUO Yan-Jun( ) 1;1) LAI Xiao-Yu( ) 2;2) XU Ren-Xin( ) 1,3;3)

Cited by 28 publications

References 35 publications

4U 1746–37: An ultra‐low‐mass compact star candidate

4U 1746–37: An ultra‐low‐mass compact star candidate

An Ultra-Low-Mass and Small-Radius Compact Object in 4u 1746-37?

Strangeon Stars

Contact Info

Product

Resources

About