A roadmap to strange star

Xu, R. X.; Lai, Xiaoyu; Xia, Caichu

doi:10.1002/asna.202113927

Cited by 5 publications

(7 citation statements)

References 26 publications

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“…According to the magnetospheric geometry of this pulsar (Wang et al 2023b), we analyze the single pulses in order to unravel the radiation characteristics and the stellar surface of this pulsar even further. It is then evident that the non-symmetrical sparking may hint "zits" on a pulsar surface (Xu & Wang 2023).…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…Besides the puzzling magnetospheric activity, to be related closely to the nature of pulsar surface, understanding pulsar's inner structure (i.e., the equation of state of supra-nuclear matter at low temperature) should be more challenging in today's physics and astrophysics. As for the state of dense supra-nuclear matter, neutronization was proposed for "gigantic nudelus" more than 90 years ago (Landau 1932), but strangonization has also been conjectured (Lai & Xu 2017;Xu 2003) after the establishment of the standard model of particle physics. The latter is the focus of this paper, and we are investigating the observational consequence of preferential discharges for PSR B0950 + 08 as an example, since small hills would grow naturally on the surface of strangeon matter with rigidity, and sparking may occur preferentially around the hills.…”

Section: Introductionmentioning

confidence: 99%

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Non‐symmetrical sparking may hint “zits” on a pulsar surface

Wang,

Lu,

Jiang

et al. 2024

Astron Nachr

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Pulsar electrodynamics could be relevant to the physics of stellar surface, which remains poorly understood for more than half a centenary and is difficult to probe due to the absence of direct and clear observational evidence. Nevertheless, highly sensitive telescopes (e.g., China's Five‐hundred‐meter Aperture Spherical radio Telescope, FAST) may play an essential role to solve the problem since the predicted surface condition would have quite different characteristics in some models of pulsar structure, especially after the establishment of the standard model of particle physics. For instance, small hills (or “zits”) may exist on solid strangeon star surface with rigidity, preferential discharge, that is, gap sparking, may occur around the hills in the polar cap region. In this work, with the 110‐min polarization observation of PSR B095008 targeted by FAST, we report that the gap sparking is significantly non‐symmetrical to the meridian plane on which the rotational and magnetic axes lie. It is then speculated that this asymmetry could be the result of preferential sparking around zits which might rise randomly on pulsar surface. Some polarization features of both single pulses and the mean pulse, as well as the cross‐correlation function of different emission regions, have also been presented.

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Section: Conclusion and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Non‐symmetrical sparking may hint “zits” on a pulsar surface

Wang,

Lu,

Jiang

et al. 2024

Astron Nachr

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“…This is a question meaningful not only in thought experiments but also in understanding realistic stuff of compact stars and even dark matter, to be solved potentially in the era of gravitational-wave astronomy (e.g., Baiotti 2019). Historically, exactly 90 years ago, Lev Landau proposed that neutron ("protons and electrons ... very close together" in his words) matter forms when a huge number of atomic nuclei come in close contact after a gravitational collapse (Landau 1932), but the building units of such resultant matter could be quarks or strangeons if the symmetry restoration of three-flavour quarks (u, d and s) works there (see, e.g., Xu et al (2021) for a brief note about the long history). How can we test these speculated models by observations?…”

Section: Introductionmentioning

confidence: 99%

Quakes of compact stars

Yue

Lai

et al. 2023

Monthly Notices of the Royal Astronomical Society

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Glitches are commonly observed for pulsars, which are explained by various mechanisms. One hypothesis attributes the glitch effect to the instantaneous moment of inertia change of the whole star caused by a starquake, which is similar to earthquakes caused by fast dislocation occurring on planar faults for the static stress, though the quake-induced dynamics responsible for glitch (superfluid vortex vs. pure starquake) remains still unknown. However, a theoretical model to quantitatively explain the stress loading, types of starquakes, and co-seismic change of moment of inertia is rarely discussed. In this study, we incorporate elastic deformation theories of earthquakes into the starquake problems. We compute the field of stress loading associated with rotation deceleration and determine the optimal type of starquakes at various locations. Two types of pulsar structure models, i.e. neutron and strangeon star models, are included in the computation and their differences are notable. Our calculation shows that the observed glitch amplitude can be explained by the starquakes in the strangeon star model, though the required scaled starquake magnitude is much larger than that occurred on the Earth. We further discuss the possibility to compute the energy budget and other glitch phenomena using the starquake model in the elastic medium framework.

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“…It is still under debate if the main constitution of pulsar-like compact stars is twoflavored or three-flavored matter. The gravity-compressed matter produced after a core-collapse supernova of an evolved massive star is currently speculated be either neutron matter or strange matter, and a historical roadmap to these ideas is introduced briefly by Xu et al (2021).…”

Section: Introductionmentioning

confidence: 99%

Merging strangeon stars II: the ejecta and light curves

Lai¹,

Xia²,

Yu³

et al. 2021

Res. Astron. Astrophys.

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The state of supranuclear matter in compact stars remains puzzling, and it is argued that pulsars could be strangeon stars. The consequences of merging double strangeon stars are worth exploring, especially in the new era of multi-messenger astronomy. To develop the “strangeon kilonova” scenario proposed in Paper I, we make a qualitative description about the evolution of ejecta and light curves for merging double strangeon stars. In the hot environment of the merger, the strangeon nuggets ejected by tidal disruption and hydrodynamical squeezing would suffer from evaporation, in which process particles, such as strangeons, neutrons and protons, are emitted. Taking into account both the evaporation of strangeon nuggets and the decay of strangeons, most of the strangeon nuggets would turn into neutrons and protons, within dozens of milliseconds after being ejected. The evaporation rates of different particles depend on temperature, and we find that the ejecta could end up with two components, with high and low opacity respectively. The high opacity component would be in the directions around the equatorial plane, and the low opacity component would be in a broad range of angular directions. The bolometric light curves show that the spin-down power of the long-lived remnant would account for the whole emission of kilonova AT2017gfo associated with GW170817, if the total ejected mass ∼ 10−3 M ⊙. The detailed picture of merging double strangeon stars is expected to be tested by future numerical simulations.

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A roadmap to strange star

Cited by 5 publications

References 26 publications

Non‐symmetrical sparking may hint “zits” on a pulsar surface

Non‐symmetrical sparking may hint “zits” on a pulsar surface

Quakes of compact stars

Merging strangeon stars II: the ejecta and light curves

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