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 last 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)

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]

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 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 . From my limited understanding of relativistic gravity it appears that the gravitational binding energy of ultra relativistic matter or light in a star would 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. It looks like this star would contain light within the surprisingly high radius of 6GM/(c^2), or 3 times the Schwarzchild radius. This might help explain the observed measurements of black hole size. 172.162.231.22 (talk) 22:29, 16 November 2013 (UTC)BG

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)


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