Strange Star Surface: A Crust with Nuggets

Jaikumar, Prashanth; Reddy, Sanjay; Steiner, Andrew W.

doi:10.1103/physrevlett.96.041101

Cited by 136 publications

(184 citation statements)

References 27 publications

(48 reference statements)

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“…Moreover it would be interesting to study whether strangelet crystals could form on the star surface [47]. One should investigate whether these strangelet nuggets might coexist with the CCSC phase, presumably assuming that the surface tension of quark matter is not too large, eventually leading to a drastic reduction of the surface charge density.…”

Section: Discussionmentioning

confidence: 99%

Electromagnetic signals from bare strange stars

et al. 2014

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The crystalline color superconducting phase is believed to be the ground state of deconfined quark matter for sufficiently large values of the strange quark mass. This phase has the remarkable property of being more rigid than any known material. It can therefore sustain large shear stresses, supporting torsional oscillations of large amplitude. The torsional oscillations could lead to observable electromagnetic signals if strange stars have a crystalline color superconducting crust. Indeed, considering a simple model of strange star with a bare quark matter surface, it turns out that a positive charge is localized in a narrow shell about ten Fermi thick beneath the star surface. The electrons needed to neutralize the positive charge of quarks spill in the star exterior forming an electromagnetically bounded atmosphere hundreds of Fermi thick. When a torsional oscillation is excited, for example by a stellar glitch, the positive charge oscillates with typical kHz frequencies, for a crust thickness of about one-tenth of the stellar radius, to hundreds of Hz, for a crust thickness of about nine-tenths of the stellar radius. Higher frequencies, of the order of few GHz, can be reached if the star crust is of the order of few centimeters thick. We estimate the emitted power considering emission by an oscillating magnetic dipole, finding that it can be quite large, of the order of 10 45 erg/s for a thin crust. The associated relaxation times are very uncertain, with values ranging between microseconds and minutes, depending on the crust thickness. The radiated photons will be in part absorbed by the electronic atmosphere, but a sizable fraction of them should be emitted by the star.

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Section: Discussionmentioning

confidence: 99%

Electromagnetic signals from bare strange stars

et al. 2014

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“…A strange star with M ns = 1.5 M can have a nuclear crust of only 100-500 m thickness (Glendenning & Weber 1992). Recently, it was proposed by Jaikumar et al (2006) that the crust of strange stars can be composed of strange quark nuggets and electrons. The thickness of such a crust is calculated to be just 50 m. The neutrino mean free path is then similar to a bare strange star, and one can ignore effects from the neutrino interactions, so that the final kick is maximal.…”

Section: Eν Mementioning

confidence: 99%

Pulsar kicks by anisotropic neutrino emission from quark matter in strong magnetic fields

Sagert¹,

Schaffner-Bielich²

2008

A&A

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Aims. We critically discuss a pulsar acceleration mechanism based on asymmetric neutrino emission from the direct quark Urca process in the interior of proto neutron stars. Methods. The neutrinos are emitted by the cooling strange quark matter core with an anisotropy caused by a strong magnetic field. We calculate the kick velocity of the proto neutron star in dependence of the temperature and radius of the quark phase. The results are compared with the necessary magnetic field strength, as well as the neutrino mean free path. Results. We find that within a quark phase radius of 10 km and temperatures higher than 5 MeV kick velocities of 1000 km s −1 can be reached only when neutrino quark scattering is ignored. When taking the neutrino mean free paths in quark matter into account kick velocities higher than 100 km s −1 cannot be reached. The same holds even when effects from colour superconductivity are included. For pulsar kicks powered by quark phase transitions from an ungapped quark phase to the CFL phase the final velocity depends crucially on the pairing gap and the quark chemical potential and reaches 1000 km s −1 only in marginal cases. Conclusions. We find that the phenomenon of pulsar kick velocities higher than 100 km s −1 cannot be explained by asymmetric neutrino emission from either cooling normal strange quark or colour superconducting quark matter due to the small neutrino mean free paths. If neutrinos are produced by a phase transition to colour-superconducting quark matter, high kick velocities can only be reached for temperatures below 1 MeV.

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“…This change is most easily interpreted as the result of starquakes in the less dense, more familiar matter on top of the neutron core. It is difficult to explain these glitches with SQSs since there is a limit to the mass of a familiar matter crust that can rest on a SQM core [47] (although one SQM model appears to do so [48]). Then there are the explosions from time to time on soft gamma ray repeaters (SGRs).…”

Section: Are They There?mentioning

confidence: 99%

Charges on strange quark nuggets in space

et al. 2009

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Since Witten's seminal 1984 paper on the subject, searches for evidence of strange quark nuggets (SQNs) have proven unsuccessful. In the absence of experimental evidence ruling out SQNs, the validity of theories introducing mechanisms that increase their stability should continue to be tested. To stimulate electromagnetic SQN searches, particularly space searches, we estimate the net charge that would develop on an SQN in space exposed to various radiation baths (and showers) capable of liberating the SQN's less strongly bound electrons, taking into account recombination with ambient electrons. We consider, in particular, the cosmic microwave background , radiation from the sun, and diffuse galactic and extragalactic ultraviolet backgrounds. The largest charge,for the settings considered, develops on a solar system SQN exposed to a solar X-ray flare. A possible dramatic signal of SQNs in explosive astrophysical events is noted.

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Strange Star Surface: A Crust with Nuggets

Cited by 136 publications

References 27 publications

Electromagnetic signals from bare strange stars

Electromagnetic signals from bare strange stars

Pulsar kicks by anisotropic neutrino emission from quark matter in strong magnetic fields

Charges on strange quark nuggets in space

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