Talk:Quark star

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Strange Matter[edit]

I can't decide whether strange stars deserve their own article, separate from strange matter. There is a Danish-language article on strange stars, so we get a nice interwiki link, and they make more sense if they link articles on the same things. But on the other hand, everything that one can say about a strange star is also something about strange matter, so we can't really remove the information from strange matter that I've moved here... Oh, I'll think about it later... -- Oliver P. 19:30 19 Jun 2003 (UTC)


It might be good to talk about Strange Matter/Quark Matter (I'd advocate the latter terminology) purely in terms of the physics of degenerate matter and the debate over it's plausibility (ie, does QCD allow the arrangement? Is the degeneracy pressure provided by the strong nuclear force strictly analogous to neutron or electron degeneracy pressure? Are exotic quark flavors required or implied by the theory?) and move the bulk of the astrophysical considerations to this writeup.

-Peter

Giant Hadron?

The star then becomes known as a "quark star" or "strange star", similar to a single gigantic hadron (but bound by gravity rather than the color force).

The force of gravity may have much to do with the binding of such a star, but wouldn't the color force also contribute to the binding energy? -- User:Kryptid Nov 2006

I have to say, is this an entirely appropriate line to include in the introduction to this article? Surely stating that a quark star is like a giant hadron is akin to stating that a neutron star is like a giant atomic nucleus -- misleading and factually inaccurate.
Not being an expert, I'd move for a second opinion, but I think that line should be reworded. --InvaderXan (talk) 13:48, 3 December 2009 (UTC)
Giant Hardon!
I don't know about the rest of you(s) but my Giant Hardon defies gravity and is not bound by it.
Epic Typo for the Win.
"Some of these quarks may then become strange quarks and form strange matter. The star then becomes known as a "quark star" or "strange star", similar to a single gigantic hardon (but bound by gravity rather than the strong force)"

August 9,2011 — Preceding unsigned comment added by 78.32.66.91 (talk) 00:21, 10 August 2011 (UTC)

Answers

Hello to all above in this section on "Strange Matter". Quark matter is highly unstable except under very extreme conditions of high temperature and/or pressure. This instability might change radically, by the introduction of strange quarks, at least if the Bodmer-witten assumption turns out to hold true. Therefore it is important to discuss strange quark matter in relation to quark matter and it is also important to discuss strange stars in relation to quark stars. If the Bodmer-Witten hypothesis is wrong, quark and strange stars will always by hybrid stars and could only exist as a subgroup of neutron stars. The whole idea of writing a separate article on quark stars, apart from neutron stars, is the Bodmer-Witten assumption, that strange quark matter is stable at low temperatures and pressures.

I have rewritten part of the article now and supplied some vital information on the differences and similarities of quark stars and strange stars. It can still be improved - especially the discussion on the binding forces of the "giant hadron" (not misspelled! :) and certainly the section on the "characteristics" of these stars -, but I believe the basics are represented in the article as of now. RhinoMind (talk) 13:45, 14 April 2014 (UTC)

Quark Star[edit]

Shouldn't this article redirect to Quark Star or vice versa?

--User:Killroy

Quark non-strange star[edit]

Is it strictly necessary to have strange quarks? If not then "Strange star" requres splitting into a separate section. Zzzzzzzzzzz 03:22, 10 June 2006 (UTC)

See discussion under "Strange Matter" above. And my comment specifically :-) RhinoMind (talk) 13:39, 22 April 2014 (UTC)

Sources[edit]

Wired, Popular Science, and Astronomy Picture of the Day are not authoritative sources. Please replace these references with links to the papers they cite (or quote but don't cite).--Cherlin (talk) 21:40, 17 January 2008 (UTC)

This article needs a serious overhaul. I hope to get to it in the near future, now that strangelet is in decent shape. Dark Formal (talk) 16:10, 6 February 2008 (UTC)

Size of Quark Star composed of ultra relativistic material[edit]

Revised: All the contents of a light containing star would be expected to be ultra relativistic. If the pressure P of ultra relativistic material is given as (rho)(c^2)/3 [where rho is the energy density], the total supporting energy or viral energy of this star would be ∫PdV = (Mc^2)/3, meaning a whopping 1/3 of the mass energy of the star would be used just to oppose the force of gravity. The Newtonian gravitational binding energy of a gas star is considered to be about G(M^2)/R . I do not know the formula for the gravitational binding energy of an ultra relativistic star - does someone know this or how to calculate this? Is the Newtonian ratio of viral energy to binding energy the same for ultra relativistic material? From my limited understanding of relativistic gravity it appears that the gravitational binding energy of an ultra relativistic star could be twice the newtonian value, or 2G(M^2)/R . Using the viral equation, if (Mc^2)/3 is equal to 1/2 the gravitational binding energy, or G(M^2)/R, the radius R of this star equals 3GM/(c^2), or 1.5 times the Schwarzchild radius. I do not know if this figure of 1.5 times the Schwarzchild radius is correct, maybe these calculations have a cancelation of errors. But note if a star of about 1.5 - 2 times the Schwarzchild radius exists it would still contain light but not as well as a singularity of the same mass; it would contain light up to a little less than 2 to 3 times the Schwarzchild radius. There is observational evidence that this type of star is contained in a black hole: (1) Some black holes eject more energy than would be expected. (2) Some super massive black holes have been observed spinning at about 1/10 RPM, which implies a star of very large radius. The existance of an about 1.5 - 2 Schwarzchild radius star, instead of a conventional black hole point singularity, would probably mean the end of the conventional big bang model as coming from a point singularity. If 2 approximately equal mass 1.5 - 2 Schwarzchild radius stars merged the contents would be expected to be ejected at the speed of light from the contact point. This model could explain where our inflationary universe came from. It could also explain a possible ancient explosion at the center of M87. 172.162.231.22 (talk) 22:29, 16 November 2013 (UTC)BG

Hello. What you are discussing here, has nothing to do with Quark Stars. If it is of any relevance at all, it would be on the talk page on black holes. I dont think it is even relevant there, as what you are writing about and searching for is an engaged discussion about your ideas about black holes and ultra relativistic stars, ie. something that could and should be discussed in a completely different fora than Wikipedia. If you need me to clarify specific details as to why this has nothing to do with Quark Stars, please post your questions below. Most of them however, will explain themselves to you, if you study the subject of Quark Stars on your own first. RhinoMind (talk) 00:10, 12 May 2014 (UTC)

Simply stated, by a Quark star do you mean a neutron star with some quark matter production in the core? If so, shouldn't there simultaneously be much larger radiation production that the star would not contain? — Preceding unsigned comment added by 172.162.3.65 (talk) 21:44, 19 May 2014 (UTC)

Is this a question to me? If so you need to use the ":" marks. Whoever the question was meant for, I believe I can answer it anyway: 1. Please read the article on what defines a Quark Star. 2. There is no particle reactions going on inside the quark matter, so there will be no production of light or other particles. Only when matter from the outside gets in contact with the qm, will there be some reactions and glitches will occur. Possibly gamma-glitches. 3. There will however be some residual heat radiating from the quark matter itself, just as well as from the degenerate neutron matter. The heat is caused by the supernova-process and is a manifestation of converted angular momentum and gravitational energy. Read about the Viral Theorem fx.. There is no differences from how ordinary neutron stars will behave in this respect. 4. Whatever happens inside the quark matter, it will all be hold together by gravity and will not dissolve, due to the incredibly strong forces of the neutron degenerate lattice surrounding it. RhinoMind (talk) 22:26, 19 May 2014 (UTC)

If neutrons in the core disintegrated collider results indicate that about 90% of the neutron mass should be converted to gamma rays (which would exit the star) and about 10% of the neutron mass should be converted to quark matter. Quark matter is mostly charged particles associated with high energy and should quickly recombine in a neutron star to form conventional nuclei. I don't see how quark matter could exist in a stable neutron star core in the way you describe. — Preceding unsigned comment added by 172.129.21.166 (talk) 23:55, 25 May 2014 (UTC)

Ah, I think I get your drift now? Yes, if the stellar core of the nova is small enough and light enough, it cannot resist the heavy radiation pressure bouncing back, when the neutron star/hybrid star (with quark matter core) is produced and the whole thing will disintegrate, just as you describes it. However, for a neutron star to be born in the first place, the core will be rather massive and the gravitational pressure will be exactly huge enough to resist the radiation pressure from the conversion-processes. It all depends on gravitation and mass (almost).
You are touching a very central issue in relation to stars in general here. A stars life is a balance between gravitational collapse and outward radiation pressure. If one of these opposing forces wins, the star will disintegrate. This holds true for all stars. A life in the balance :-) RhinoMind (talk) 00:34, 16 August 2014 (UTC)

The section on 'Strange stars'[edit]

As of now, the section on Strange Stars does not describe what a strange star is. RhinoMind (talk) 23:44, 5 March 2014 (UTC)

I have done some preliminary work by explaining what quark and strange stars are in the new "Creation" section. The "Strange Star" section still needs to be rewritten. RhinoMind (talk) 04:16, 15 March 2014 (UTC)
I believe I have cleared up this problem by now. From now on, the article calls for an elaboration on the characteristics of quark stars and strange stars specifically. RhinoMind (talk) 23:27, 13 April 2014 (UTC)

Dark matter[edit]

I cut this paragraph from the article:

It is speculated and subject to scientific investigation if (strange) quark matter once formed, might in fact be stable under zero external pressure (ie. in interstellar space). Nuggets of (strange) quark matter is thus one of several candidates for the theoretical and unknown dark matter, featured in many cosmological theories.[1][2]

References

  1. ^ Witten, Edward (1984). "Cosmic separation of phases". Physical Review D 30 (2): 272–285. Bibcode:1984PhRvD..30..272W. doi:10.1103/PhysRevD.30.272. 
  2. ^ Zhitnitsky, Ariel R (2003). "'Nonbaryonic' dark matter as baryonic colour superconductor". Journal of Cosmology and Astroparticle Physics 2003 (10): 010–010. arXiv:hep-ph/0202161. Bibcode:2003JCAP...10..010Z. doi:10.1088/1475-7516/2003/10/010. 

I think it first and foremost belongs to the article on quark matter and strange quark matter respectively. It can be fitted in here as well, but it would need a solid explanation on how quark stars contribute with nuggets. They would indeed do if they exist in the first place, but it would need an explanation.

RhinoMind (talk) 01:59, 6 March 2014 (UTC)

On the section: "Other theorized quark formations"[edit]

The presence of this section needs a good explanation. The quark states discussed here, is more related to neutron stars, than quark stars. The various quark states might form at the core of neutron stars, under the extreme pressure and temperature, but they are not equivalent to what we know as quark matter.

The section at hand, has been discussed for various reasons previously. For the sake of structure and readability, I have collected these comments and discussions below.

RhinoMind (talk) 13:20, 14 April 2014 (UTC)

Theorized Quark Formations[edit]

This section should be deleted. First of all, to requote the Pentaquark page, there is "overwhelming evidence that the claimed pentaquarks do not exist".[1] The idea of 4, 5, and 6 quark hadrons has been discarded by the particle physics community. But this is besides the point, theoretical hadrons have nothing to do with structure of a quark star. It would be more appropriate to reference Quark-gluon plasma. Pulu (talk) 05:54, 27 August 2012 (UTC)

I also think that this section is not relevant. Mi Tatara Buela (talk) 14:40, 20 November 2013 (UTC)

Classification[edit]

All Strange stars are Quark stars. But, not all Quark stars are Strange stars. Other Quark Stars. Strange Exotic States and Compact Stars

  • Jaffe 1977, suggested a four-quark state with strangeness (qsqs
  • H-dibaryon, a six-quark state with equal numbers of up-, down-, and strange quarks (uuddss)
  • bound multi-quark systems with heavy quarks QQqq
  • pentaquark states were first proposed with a charm anti-quark (qqqsc), 1987
  • pentaquark state with an antistrange quark & four light quarks consisting of up- and down-quarks only (qqqqs)
  • light pentaquarks are grouped within an antidecuplet, the lightest candidate, Ө+ (big epsilon)
    • can also be described by the diquark model of Jaffe and Wilczek (QCD)
  • Ө++ (big epsilon) & antiparticle Ө--
  • doubly strange pentaquark (sssddu), memeber of the light pentaquark antidecuplet
  • charmed pentaquark Өc(3100) (uuddc) state was detected by the H1 collaboration

http://xxx.lanl.gov/abs/astro-ph/0608317 Thanks, CarpD 1/07/06

Almost all of the particles suggested here contain strange quarks, and thus do not support your assertion.--Cherlin (talk) 21:40, 17 January 2008 (UTC)
almost is not the same as all - so it does support his assertion, since atleast one is not strange. 76.66.197.2 (talk) 06:51, 27 November 2009 (UTC)
Hello. You are right. As strange quark matter is a specific subgroup under quark matter, so are strange stars a subgroup under quark stars. The quark matter that might theoretically form in the core of neutron stars, can be very exotic and show a high degree of diversity though. Charm quark matter have also been discussed in the literature fx..
As the article is now here in 2014, I can see that this issue is no longer a problem? RhinoMind (talk) 23:24, 13 April 2014 (UTC)