{{Short description|Hypothetical types of stars}} {{Use dmy dates|date=August 2018}} An '''exotic star''' is a hypothetical compact star composed of exotic matter (something not made of electrons, protons, neutrons, or muons), and balanced against gravitational collapse by degeneracy pressure or other quantum properties.
Types of exotic stars include * quark stars (composed of quarks) * strange stars (composed of strange quark matter, a condensate of up, down, and strange quarks) * preon stars (speculative material composed of preons, which are hypothetical particles and "building blocks" of quarks and leptons, should quarks be decomposable into component sub-particles).
Of the various types of exotic star proposed, the most well evidenced and understood is the quark star, although its existence is not confirmed.
==Quark stars and strange stars== {{main|Quark star|Strange star}} A '''quark star''' is a hypothesized object that results from the decomposition of neutrons into their constituent quarks under extremely intense gravitational pressure balanced by electrical repulsion and degeneracy pressure.<ref>{{Cite journal |last=Ivanenko |first=D. D. |last2=Kurdgelaidze |first2=D. F. |date=1967 |title=Hypothesis concerning quark stars |url=http://link.springer.com/10.1007/BF01042830 |journal=Astrophysics |language=en |volume=1 |issue=4 |pages=251–252 |doi=10.1007/BF01042830 |issn=0571-7256|url-access=subscription }}</ref><ref>{{Cite journal |last=Oks |first=Eugene |date=2021-12-01 |title=Brief review of recent advances in understanding dark matter and dark energy |url=https://www.sciencedirect.com/science/article/pii/S1387647321000191 |journal=New Astronomy Reviews |volume=93 |article-number=101632<!--Despite the BibTeX citation giving this as page number, it is in fact article number--> |doi=10.1016/j.newar.2021.101632 |issn=1387-6473|arxiv=2111.00363 }}</ref> Such a star would be smaller and denser than a neutron star, and may survive in this new state indefinitely, if no extra mass is added. Quark stars that contain strange matter are called '''strange stars'''.<ref>{{Cite journal |last=Farhi |first=Edward |last2=Jaffe |first2=R. L. |date=1984-12-01 |title=Strange matter |url=https://link.aps.org/doi/10.1103/PhysRevD.30.2379 |journal=Physical Review D |language=en |volume=30 |issue=11 |pages=2379–2390 |doi=10.1103/PhysRevD.30.2379 |issn=0556-2821|url-access=subscription }}</ref> Such a star, first proposed by Edward Witten, would consist of confined quarks, essentially a giant nucleon.<ref>{{Cite journal |last=Celotti |first=A. |last2=Miller |first2=J. C. |last3=Sciama |first3=D. W. |date=1999-12-01 |title=Astrophysical evidence for the existence of black holes |url=https://iopscience.iop.org/article/10.1088/0264-9381/16/12A/301 |journal=Classical and Quantum Gravity |volume=16 |issue=12A |pages=A3–A21 |doi=10.1088/0264-9381/16/12A/301 |issn=0264-9381|arxiv=astro-ph/9912186 }}</ref>
Based on observations released by the Chandra X-Ray Observatory on 10 April 2002, two objects, named RX J1856.5−3754 and {{nobr|3C 58,}} were suggested as quark star candidates. The former appeared to be much smaller and the latter much colder than expected for a neutron star, suggesting that they were composed of material denser than neutronium. However, these observations were met with skepticism by researchers who said the results were not conclusive.{{Who|date=August 2011}} After further analysis, RX J1856.5−3754 was excluded from the list of quark star candidates.<ref name=Truemper2004> {{cite journal | last1 = Truemper | first1 = J. E. | last2 = Burwitz | first2 = V. | last3 = Haberl | first3 = F. | last4 = Zavlin | first4 = V. E. | date = June 2004 | title = The puzzles of RX J1856.5-3754: neutron star or quark star? | journal = Nuclear Physics B: Proceedings Supplements | volume = 132 | pages = 560–565 | doi = 10.1016/j.nuclphysbps.2004.04.094 | s2cid = 425112 | bibcode = 2004NuPhS.132..560T | arxiv = astro-ph/0312600 }} </ref>
==Electroweak stars== An '''electroweak star''' is a hypothetical type of exotic star in which the gravitational collapse of the star is prevented by radiation pressure resulting from electroweak burning; that is, the energy released by the conversion of quarks to leptons by the electroweak force. This proposed process might occur in a volume at the star's core approximately the size of an apple, containing about two Earth masses, and reaching temperatures on the order of 10<sup>15</sup> K (1 PK).<ref name = "Dai">{{Cite journal |last1=Dai |first1=De-Chang |last2=Lue |first2=Arthur |last3=Starkman |first3=Glenn |last4=Stojkovic |first4=Dejan |date=2010-12-06 |title=Electroweak stars: How nature may capitalize on the standard model's ultimate fuel |journal=Journal of Cosmology and Astroparticle Physics |volume=2010 |issue=12 |page=004 |doi=10.1088/1475-7516/2010/12/004 |issn=1475-7516|arxiv=0912.0520 |bibcode=2010JCAP...12..004D |s2cid=118417017 }}</ref><ref name=newscientist> {{cite magazine |author=Shiga, D. |date=4 January 2010 |title=Exotic stars may mimic Big Bang |magazine=New Scientist |url=https://www.newscientist.com/article/dn18334-exotic-stars-may-mimic-big-bang.html |access-date=2010-02-18 |url-status=live |archive-url=https://web.archive.org/web/20100118074423/https://www.newscientist.com/article/dn18334-exotic-stars-may-mimic-big-bang.html |archive-date=18 January 2010 }} </ref> Electroweak stars could be identified through the equal number of neutrinos emitted of all three generations, taking into account neutrino oscillation.<ref name = "Dai"/>
==Preon stars{{anchor|Preon_star}}==
A '''preon star''' is a proposed type of compact star made of preons, a group of hypothetical subatomic particles. Preon stars would be expected to have huge densities, exceeding {{10^|23}} kg/m<sup>3</sup>. They may have greater densities than quark stars, and they would be heavier but smaller than white dwarfs and neutron stars.<ref>{{cite journal |last1=Hannson |first1=J. |last2=Sandin |first2=F. |date=9 June 2005 |title=Preon stars: A new class of cosmic compact objects |journal=Physics Letters B |volume=616 |issue=1–2 |pages=1–7 |doi=10.1016/j.physletb.2005.04.034 |arxiv = astro-ph/0410417 |bibcode = 2005PhLB..616....1H |s2cid=119063004}}</ref>
==Boson stars== A '''boson star''' is a hypothetical astronomical object formed out of particles called bosons. Conventional stars are formed from mostly protons and electrons, which are fermions, but also contain a large proportion of helium-4 nuclei, which are bosons, and smaller amounts of various heavier nuclei, which can be either. For this type of star to exist, there must be a stable type of boson with self-repulsive interaction; one possible candidate particle<ref> {{cite journal |author=Kolb, Edward W. |author2=Tkachev, Igor I. |date= 29 March 1993 |title=Axion miniclusters and Bose stars |journal=Physical Review Letters |volume=71 |issue=19 |pages=3051–3054 |bibcode=1993PhRvL..71.3051K |arxiv=hep-ph/9303313 |doi=10.1103/PhysRevLett.71.3051 |pmid=10054845 |s2cid=16946913 }} </ref> is the still-hypothetical "axion" (which is also a candidate for the not-yet-detected "non-baryonic dark matter" particles, which appear to compose roughly 25% of the mass of the Universe). It is theorized<ref> {{cite news | author=Clark, Stuart | date=15 July 2017 | title=Holy moley! (Astronomers taking a first peek at our galaxy's black heart might be in for a big surprise) | magazine=New Scientist | page=29 }} </ref> that unlike normal stars (which emit radiation due to gravitational pressure and nuclear fusion), boson stars would be transparent and invisible. The immense gravity of a compact boson star would bend light around the object, creating an empty region resembling the shadow of a black hole's event horizon. Like a black hole, a boson star would absorb ordinary matter from its surroundings, but because of the transparency, matter (which would probably heat up and emit radiation) would be visible at its center. Rotating boson star models are also possible. Unlike black holes these have quantized angular momentum, and their energy density profiles are torus-shaped, which can be understood as a result of deformation due to centrifugal forces.<ref> {{cite journal |last1 = Yoshida |first1 = Shijun |last2 = Eriguchi |first2 = Yoshiharu |year = 1997 |title = Rotating boson stars in general relativity |journal = Physical Review D |volume = 56 |issue = 2 |page = 762 |doi=10.1103/PhysRevD.56.762 |bibcode = 1997PhRvD..56..762Y |url=https://journals.aps.org/prd/abstract/10.1103/PhysRevD.56.762 }} </ref>
There is no significant evidence that such stars exist. However, it may become possible to detect them by the gravitational radiation emitted by a pair of co-orbiting boson stars.<ref> {{cite book | first=Bernard F. | last=Schutz | year=2003 | title=Gravity from the Ground Up | edition=3rd | publisher=Cambridge University Press | isbn=0-521-45506-5 | url=https://archive.org/details/gravityfromgroun00schu_469 | url-access=limited | page=[https://archive.org/details/gravityfromgroun00schu_469/page/n170 143] }} </ref><ref> {{cite journal | author1=Palenzuela, C. | author2=Lehner, L. | author3=Liebling, S.L. | date=2008 | title=Orbital dynamics of binary boson star systems | journal=Physical Review D | volume=77 | issue=4 | article-number=044036 | doi=10.1103/PhysRevD.77.044036 | s2cid=115159490 | bibcode = 2008PhRvD..77d4036P | arxiv = 0706.2435 }} </ref> GW190521, thought to be the most energetic black hole merger ever recorded, may be the head-on collision of two boson stars.<ref> {{cite journal |last1 = Bustillo |first1 = Juan Calderón |last2 = Sanchis-Gual |first2 = Nicolas |last3 = Torres-Forné |first3 = Alejandro |last4 = Font |first4 = José A. |last5 = Vajpeyi |first5 = Avi |last6 = Smith |first6 = Rory |last7 = Herdeiro |first7 = Carlos |last8 = Radu |first8 = Eugen |last9 = Leong |first9 = Samson H.W. |display-authors = 6 |year = 2021 |title = GW190521 as a merger of Proca stars: A potential new vector Boson of 8.7×{{10^|−13}} eV |journal = Physical Review Letters |volume = 126 |issue = 8 |article-number = 081101 |pmid = 33709746 |arxiv=2009.05376 |hdl = 10773/31565 |s2cid = 231719224 |doi = 10.1103/PhysRevLett.126.081101 |url=https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.126.081101 }} </ref> In addition, gravitational wave signals from compact binary boson star mergers can be degenerate with those from black hole mergers, suggesting that some gravitational wave observations interpreted as originating in a black hole binary could really originate in a boson star binary.<ref> {{cite journal |last1 = Evstafyeva |first1 = Tamara |last2 = Sperhake |first2 = Ulrich |last3 = Romero-Shaw |first3 = Isobel M. |last4 = Agathos |first4 = Michalis |year = 2024 |title = Gravitational-Wave Data Analysis with High-Precision Numerical Relativity Simulations of Boson Star mergers |journal = Physical Review Letters |volume = 133 |issue = 13 |article-number = 131401 |arxiv=2406.02715 |s2cid = 231719224 |doi = 10.1103/PhysRevLett.133.131401 |pmid = 39392956 |bibcode = 2024PhRvL.133m1401E |url=https://link.aps.org/doi/10.1103/PhysRevLett.133.131401 }} </ref> The invisible companion to a Sun-like star identified by Gaia mission could be a black hole or either a boson star or an exotic star of other types.<ref>{{Cite journal |last1=Pombo |first1=Alexandre M |last2=Saltas |first2=Ippocratis |date=September 2023 |title=A Sun-like star orbiting a boson star |url=https://academic.oup.com/mnras/article/524/3/4083/7226209 |journal=Monthly Notices of the Royal Astronomical Society |volume=524 |issue=3 |pages=4083–4090 |doi=10.1093/mnras/stad2151 |doi-access=free |issn=0035-8711|arxiv=2304.09140 }}</ref><ref>{{Cite web |title=This star might be orbiting a strange 'boson star' |url=https://phys.org/news/2023-05-star-orbiting-strange-boson.amp |access-date=2024-12-26 |website=phys.org |language=en}}</ref>
Boson stars may have formed through gravitational collapse during the primordial stages of the Big Bang.<ref> {{cite journal | author1=Madsen, Mark S. | author2=Liddle, Andrew R. | year=1990 | title=The cosmological formation of boson stars | journal=Physics Letters B | volume=251 | issue=4 | page=507 | doi=10.1016/0370-2693(90)90788-8 | bibcode = 1990PhLB..251..507M }} </ref> At least in theory, a supermassive boson star could exist at the core of a galaxy, resulting in effects similar to a supermassive black hole.<ref> {{cite journal | author1=Torres, Diego F. | author2=Capozziello, S. | author3=Lambiase, G. | year=2000 | title=A supermassive Boson star at the galactic center? | journal=Physical Review D | volume=62 | issue=10 | article-number=104012 | doi=10.1103/PhysRevD.62.104012 | s2cid=16670960 |arxiv = astro-ph/0004064 |bibcode = 2000PhRvD..62j4012T }}</ref> However, more recent general-relativistic magnetohydrodynamic simulations, combined with imaging performed by the Event Horizon Telescope, is believed to have largely ruled out the possibility that Sagittarius A*, the supermassive object at the center of the Milky Way, could be a boson star.<ref>{{Cite journal |last1=Olivares |first1=Hector |last2=Younsi |first2=Ziri |last3=Fromm |first3=Christian M |last4=De Laurentis |first4=Mariafelicia |last5=Porth |first5=Oliver |last6=Mizuno |first6=Yosuke |last7=Falcke |first7=Heino |last8=Kramer |first8=Michael |last9=Rezzolla |first9=Luciano |date=2020-09-01 |title=How to tell an accreting boson star from a black hole |journal=Monthly Notices of the Royal Astronomical Society |volume=497 |issue=1 |pages=521–535 |doi=10.1093/mnras/staa1878 |doi-access=free |issn=0035-8711|arxiv=1809.08682 }}</ref>
Bound states in cosmological bosonic fields have also been proposed as an alternative to dark matter.<ref>{{Cite journal |last1=Vogelsberger |first1=Mark |last2=Marinacci |first2=Federico |last3=Torrey |first3=Paul |last4=Puchwein |first4=Ewald |date=2020-01-08 |title=Cosmological simulations of galaxy formation |url=https://www.nature.com/articles/s42254-019-0127-2 |journal=Nature Reviews Physics |language=en |volume=2 |issue=1 |pages=42–66 |doi=10.1038/s42254-019-0127-2 |issn=2522-5820|arxiv=1909.07976 }}</ref> The dark matter haloes surrounding most galaxies might be viewed as enormous "boson stars."<ref> {{cite journal |author1=Lee, Jae-weon |author2=Koh, In-guy |year=1996 |title=Galactic halos as Boson stars |journal=Physical Review D | volume=53 | issue=4 |pages=2236–2239 |pmid=10020213 |bibcode=1996PhRvD..53.2236L |s2cid=16914311 |arxiv=hep-ph/9507385 |doi=10.1103/PhysRevD.53.2236 }} </ref>
Compact boson stars and boson shells are often modelled using massive bosonic fields, such as complex scalar fields and U(1) gauge fields, coupled to gravity. The presence of a positive or negative cosmological constant in the theory facilitates a study of these objects in de Sitter and anti-de Sitter spaces.<ref> {{cite journal | author1=Kumar, S. | author2=Kulshreshtha, U. | author3=Kulshreshtha, D.S. | year = 2016 | title = Charged compact boson stars and shells in the presence of a cosmological constant | journal = Physical Review D | volume = 94 | issue = 12 | article-number = 125023 | doi = 10.1103/PhysRevD.94.125023 | s2cid=54590086 | bibcode=2016PhRvD..94l5023K | arxiv=1709.09449 }} </ref><ref> {{cite journal | author1=Kumar, S. | author2=Kulshreshtha, U. | author3=Kulshreshtha, D.S. | year = 2016 | title = Charged compact boson stars and shells in the presence of a cosmological constant | journal = Physical Review D | volume = 93 | issue = 10 | article-number = 101501 | doi=10.1103/PhysRevD.93.101501 | s2cid=118474697 | arxiv=1605.02925 | bibcode=2016PhRvD..93j1501K }} </ref><ref> {{cite journal | author1=Kleihaus, B. | author2=Kunz, J. | author3=Lammerzahl, C. | author4=List, M. | year = 2010 | title = Boson Shells Harbouring Charged Black Holes | journal = Physical Review D | volume = 82 | issue = 10 | article-number = 104050 | doi=10.1103/PhysRevD.82.104050 | arxiv=1007.1630 | bibcode=2010PhRvD..82j4050K | s2cid=119266501 }} </ref><ref> {{cite journal | author1=Hartmann, B. | author2=Kleihaus, B. | author3=Kunz, J. | author4=Schaffer, I. | year = 2013 | title = Compact (A)dS Boson stars and shells | journal = Physical Review D | volume = 88 | issue = 12 | article-number = 124033 | doi=10.1103/PhysRevD.88.124033 | arxiv=1310.3632 | bibcode=2013PhRvD..88l4033H | s2cid=118721877 }} </ref><ref> {{cite journal | author1=Kumar, S. | author2=Kulshreshtha, U. | author3=Kulshreshtha, D.S. | author4=Kahlen, S. | author5=Kunz, J. | year = 2017 | title = Some new results on charged compact boson stars | journal = Physics Letters B | volume = 772 | pages=615–620 | doi=10.1016/j.physletb.2017.07.041 | arxiv=1709.09445 | bibcode=2017PhLB..772..615K | s2cid=119375441 }} </ref>
By changing the potential associated with the matter model, different families of boson star models can be obtained. The so-called '''solitonic''' potential, which introduces a degenerate vacuum state at a finite value of the field amplitude, can be used to construct boson star models so compact that they possess a pair of photon orbits, one of which is stable.<ref>{{Cite journal |last1=Collodel |first1=Lucas G. |last2=Doneva |first2=Daniela D. |date=2022-10-28 |title=Solitonic boson stars: Numerical solutions beyond the thin-wall approximation |url=https://link.aps.org/doi/10.1103/PhysRevD.106.084057 |journal=Physical Review D |language=en |volume=106 |issue=8 |article-number=084057 |doi=10.1103/PhysRevD.106.084057 |arxiv=2203.08203 |bibcode=2022PhRvD.106h4057C |issn=2470-0010}}</ref> Because they trap light, such boson stars could mimic much of the observational phenomenology of black holes.
Boson stars composed of elementary particles with spin-1 have been labelled '''Proca stars'''.<ref> {{cite journal |last1=Brito |first1=Richard |last2=Cardoso |first2=Vitor |last3=Herdeiro |first3=Carlos A.R. |last4=Radu |first4=Eugen |date=January 2016 |title=Proca stars: Gravitating Bose–Einstein condensates of massive spin 1 particles |journal=Physics Letters B |volume=752 |pages=291–295 |doi=10.1016/j.physletb.2015.11.051 |arxiv=1508.05395 |bibcode=2016PhLB..752..291B |s2cid=119110645 |hdl=11573/1284757 |hdl-access=free |lang=en |url=https://linkinghub.elsevier.com/retrieve/pii/S0370269315009077 |access-date=25 July 2021 |url-status=live |archive-url=https://web.archive.org/web/20211125130438/https://linkinghub.elsevier.com/retrieve/pii/S0370269315009077 |archive-date=25 November 2021 }} </ref>
==Planck stars== {{Main|Planck star}}
In loop quantum gravity, a Planck star is a hypothetically possible astronomical object that is created when the energy density of a collapsing star reaches the Planck energy density. Under these conditions, assuming gravity and spacetime are quantized, there arises a repulsive "force" derived from Heisenberg's uncertainty principle. In other words, if gravity and spacetime are quantized, the accumulation of mass-energy inside the Planck star cannot collapse beyond this limit to form a gravitational singularity because it would violate the uncertainty principle for spacetime itself.<ref> {{cite journal |last1=Rovelli |first1=Carlo |last2=Vidotto |first2=Francesca |year=2014 |title=Planck stars |journal=International Journal of Modern Physics D |volume=23 |issue=12 |page=1442026 |arxiv=1401.6562 |bibcode = 2014IJMPD..2342026R |doi = 10.1142/S0218271814420267 |s2cid=118917980 }} </ref>
== Q-stars == Q-stars are hypothetical objects that originate from supernovae or the big bang. They are theorized to be massive enough to bend space-time to a degree such that some, but not all light could escape from its surface. These are predicted to be denser than neutron stars or even quark stars.<ref>{{Cite journal |last1=Bahcall |first1=Safi |last2=Lynn |first2=Bryan W |last3=Selipsky |first3=Stephen B |date=1990-02-05 |title=Are neutron stars Q-stars? |journal=Nuclear Physics B |volume=331 |issue=1 |pages=67–79 |doi=10.1016/0550-3213(90)90018-9 |issn=0550-3213|doi-access=free |bibcode=1990NuPhB.331...67B }}</ref>
== Dark stars == In Newtonian mechanics, objects dense enough to trap any emitted light are called ''dark stars'',<ref>{{Cite book |last=Israel |first=W. |url=https://ui.adsabs.harvard.edu/abs/1987thyg.book..199I/abstract |title=Three Hundred Years of Gravitation |date=1987 |publisher=Cambridge University Press. |location=United Kingdom |pages=199–276 |language=en |chapter=Dark stars: the evolution of an idea.|bibcode=1987thyg.book..199I }}</ref> as opposed to black holes in general relativity. However, the same name is used for hypothetical ancient "stars" which derived energy from dark matter.<ref>{{Cite journal |last1=Ilie |first1=Cosmin |last2=Paulin |first2=Jillian |last3=Freese |first3=Katherine |date=2023-07-25 |title=Supermassive Dark Star candidates seen by JWST |journal=Proceedings of the National Academy of Sciences |volume=120 |issue=30 |article-number=e2305762120 |doi=10.1073/pnas.2305762120 |doi-access=free |pmc=10372643 |pmid=37433001|arxiv=2304.01173 |bibcode=2023PNAS..12005762I }}</ref> Quantum effects may prevent true black holes from forming and give rise instead to dense entities called ''black stars''.<ref name=Visser-Barcelo-etal-2009-SciAm> {{cite magazine |author1 = Visser, Matt |author2 = Barcelo, Carlos |author3 = Liberati, Stefano |author4 = Sonego, Sebastiano |date = 30 September 2009 |title = How quantum effects could create black stars, not holes |magazine = Scientific American |issue = October 2009 |url = http://www.scientificamerican.com/article.cfm?id=black-stars-not-holes |access-date = 2022-12-25 |archive-url = https://web.archive.org/web/20131115192631/http://www.scientificamerican.com/article.cfm?id=black-stars-not-holes |archive-date = 2013-11-15 |quote = Originally published with title ''"Black Stars, Not Holes"''. }} </ref>
==See also== * Quasi-star * Quark nova * Degeneracy pressure
==References== {{reflist|25em}}
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==External links== * {{cite journal |author1=Miller, J.C. |author2=Shahbaz, T. |author3=Nolan, L.A. |year=1997 |title=Are Q-stars a serious threat for stellar-mass black hole candidates? |journal=Monthly Notices of the Royal Astronomical Society |volume=294 |issue=2 |pages=L25–L29 |doi=10.1111/j.1365-8711.1998.01384.x |arxiv=astro-ph/9708065 |s2cid=715726 }} * {{cite journal |author1=Abramowicz, Marek A. |author2=Kluzniak, Wlodek |author3=Lasota, Jean-Pierre |year=2002 |title=No observational proof of the black-hole event-horizon |journal=Astronomy & Astrophysics |volume=396 |issue=3 |pages=L31–L34 |doi=10.1051/0004-6361:20021645 |arxiv=astro-ph/0207270 |bibcode=2002A&A...396L..31A |s2cid=9771972 }} * {{cite magazine |title=Could preon stars reveal a hidden reality? |date=6 February 2008 |magazine=New Scientist |issue=2643 |url=https://www.newscientist.com/article/mg19726431.700-could-preon-stars-reveal-a-hidden-reality.html }} * {{cite magazine |title=Micro-stars may manage to avoid black-hole fate |date=6 November 2008 |magazine=New Scientist |issue=2472 |url=https://www.newscientist.com/article/mg18424722.300-microstars-may-manage-to-avoid-blackhole-fate.html }} * {{cite journal |author=Dai, De-Chang |author2=Lue, Arthur |author3=Starkman, Glenn |author4=Stojkovic, Dejan |year=2010 |title=Electroweak stars: How nature may capitalize on the standard model's ultimate fuel |journal=Journal of Cosmology and Astroparticle Physics |volume=2010 |issue=12 |page=004 |arxiv=0912.0520 |doi=10.1088/1475-7516/2010/12/004 |bibcode=2010JCAP...12..004D |s2cid=118417017 }} * {{cite web |date=15 December 2009 |title=Theorists Propose a New Way to Shine – And a New Kind of Star: 'Electroweak' |url=https://www.sciencedaily.com/releases/2009/12/091214131132.htm |website=ScienceDaily |access-date=2009-12-16 }} * {{cite web |date=16 December 2009 |title=A New Way To Shine, A New Kind Of Star |url=http://www.spacedaily.com/reports/A_New_Way_To_Shine_A_New_Kind_Of_Star_999.html |website=SpaceDaily |access-date=2009-12-16 }} * {{cite magazine |date=15 December 2009 |title=Theorists propose a new way to shine — and a new kind of star |url=http://www.astronomy.com/asy/default.aspx?c=a&id=8895 |magazine=Astronomy Magazine |access-date=2009-12-16 }} *{{cite web |date=10 December 2009 |title=Astronomers Predict New Class of 'Electroweak' Star |url=http://www.technologyreview.com/blog/arxiv/24505/ |website=Technology Review |access-date=2009-12-16 |archive-date=2012-10-19 |archive-url=https://web.archive.org/web/20121019220447/http://www.technologyreview.com/view/416636/astronomers-predict-new-class-of-electroweak-star/ }} * {{cite web |author=Vieru, Tudor |date=15 December 2009 |website=Softpedia |url=http://news.softpedia.com/news/New-Type-of-Cosmic-Object-Electroweak-Star-129779.shtml |title=New type of cosmic objects: Electroweak stars |access-date=2009-12-16 }} * {{Cite journal |author1=Dai, De-Chang |author2=Lue, Arthur |author3=Starkman, Glenn |author4=Stojkovic, Dejan |year=2010 |title=Electroweak stars: How nature may capitalize on the standard model's ultimate fuel |journal=Journal of Cosmology and Astroparticle Physics |volume=2010 |issue=12 |page=004 |arxiv=0912.0520 |doi=10.1088/1475-7516/2010/12/004 |bibcode=2010JCAP...12..004D |s2cid=118417017 }}
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Category:Degenerate stars Category:Hypothetical stars Category:Compact stars Category:Star types