Quark star

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A curd rating (also English strange star , rating strange ') is a hypothetical compact object , which as a product of a Super Nova ( Quark-Nova could arise). In the quark star, the matter would be so tightly packed that neutrons would lose their identity and quasi-free quarks would be present ( quark-gluon-plasma ). The English name stems from the fact that this matter would also contain strange quarks and could therefore be assigned to strange matter .

Emergence

The nuclear fusion in a star generates heat and pressure with the gravity is in equilibrium. If the nuclear fuel is used up, the matter is very strongly compressed by the remaining gravity. Depending on the mass of the star, a white dwarf , a neutron star , a (hypothetical) quark star, a (also hypothetical) gravastern or a black hole is created , sometimes accompanied by a supernova or hypernova .

There is an upper mass limit for neutron stars, the Tolman-Oppenheimer-Volkoff limit , the value of which, according to observations of the event GW170817, is approximately 2.17  solar masses . If a neutron star crosses this limit, it collapses into a black hole. However, the closer a neutron star only approaches this upper mass limit , the larger the suspected quark-gluon-plasma sphere inside it would be.

According to theoretical models, quark stars could form in X-ray binary stars of low mass. In this, matter is transferred to a neutron star by a companion. Accordingly, a neutron star would have a mass of 1.4 solar masses have 0.5 solar masses accrete to convert into a quark star. The candidate for this is V395 Carinae (2S 0921-63). However, the mass determinations in X-ray binary stars are always fraught with great uncertainties, and a mass of 1.44 solar masses, which is typical for a neutron star, cannot be ruled out.

observation

So far there have been no observations that prove that the theoretically possible compression of the neutron matter of an existing neutron star into the quark-gluon plasma of a quark star takes place in the universe . But it is possible that many neutron stars have such a plasma, at least in their interior.

Detecting a quark star is considered difficult because its remotely observable properties are similar to those of a neutron star. So far, a pulsar has been discovered as a candidate for a possible quark star:

  • PSR J0205 + 6449 in supernova remnant 3C 58 is assigned to supernova 1181 , which was observed by Japanese and Chinese astronomers in 1181. Because of its great distance of around 10,000 light years from Earth, its diameter could not yet be calculated, but its luminosity is 16 times less than that of comparable young pulsars. This could be an indication that it is a quark star.

Individual evidence

  1. ^ Matt Visser, David L Wiltshire: Stable gravastars — an alternative to black holes? In: Classical and Quantum Gravity . tape 21 , no. 4 , January 22, 2004, ISSN  0264-9381 , p. 1135–1151 , doi : 10.1088 / 0264-9381 / 21/4/027 .
  2. ^ B. Margalit, BD Metzger: Constraining the Maximum Mass of Neutron Stars from Multi-messenger Observations of GW170817 . In: The Astrophysical Journal . 850, No. 2, December 1, 2017. arxiv : 1710.05938 . bibcode : 2017ApJ ... 850L..19M . doi : 10.3847 / 2041-8213 / aa991c .
  3. ↑ M. Shibata, S. Fujibayashi, K. Hotokezaka, K. Kiuchi, K. Kyutoku, Y. Sekiguchi, M. Tanaka: Modeling GW170817 based on numerical relativity and its implications . In: Physical Review D . 96, No. 12, December 22, 2017, p. 123012. arxiv : 1710.07579 . bibcode : 2017PhRvD..96l3012S . doi : 10.1103 / PhysRevD.96.123012 .
  4. ^ M. Ruiz, SL Shapiro, A. Tsokaros: GW170817, general relativistic magnetohydrodynamic simulations, and the neutron star maximum mass . In: Physical Review D . 97, No. 2, January 11, 2018, p. 021501. arxiv : 1711.00473 . bibcode : 2018PhRvD..97b1501R . doi : 10.1103 / PhysRevD.97.021501 . PMID 30003183 . PMC 6036631 (free full text).
  5. ↑ L. Rezzolla, ER Most, LR Weih: Using Gravitational-wave Observations and Quasi-universal Relations to Constrain the Maximum Mass of Neutron Stars . In: Astrophysical Journal . 852, No. 2, January 9, 2018, p. L25. arxiv : 1711.00314 . bibcode : 2018ApJ ... 852L..25R . doi : 10.3847 / 2041-8213 / aaa401 .
  6. ↑ Chunhua Zhu, Guoliang Lv, Zhaojun Wang, Jinzhong Liu: Low-mass X-ray Binaries with Strange Quark Stars . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1303.2458v1 .
  7. ↑ Slane, PO et al .: New Constraints on Neutron Star Cooling from Chandra Observations of 3C 58 . The Astrophysical Journal, Volume 571, Issue 1, L45 – L49, 2002 ( preprint )

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