# Some black holes may actually be Quark Stars

1. Mar 18, 2010

### rhody

Some black holes may actually be "Quark Stars"

http://www.usatoday.com/tech/scienc...ies+(Tech+-+Science+and+Space+-+Top+Stories)": excerpts below:
So how is a "quark star" detected ?
http://en.wikipedia.org/wiki/Bremsstrahlung" [Broken] means braking radiation, produced by the acceleration of a charged particle when deflected by another charged particle. It was discovered over 100 years ago by Nikola Tesla.

So far, no "quark stars" have been confirmed, but:
Finally:
To summarize: Dark Stars should:

Emit (dim light) Bremsstrahlung radiation​
Have mass more than 1.4 times our sun​
Have 10% less mass than predicted around a (minimal?) black hole​
If dark stars are in fact, dark matter, they should weigh about 6 times that of normal matter​

PFer's are a pretty tough crowd, is there anything the article missed ?

Could quark stars cores contain the elusive: quark-gluon plasma created/detected at RHIC ?

Rhody...

Last edited by a moderator: May 4, 2017
2. Mar 19, 2010

### Chronos

Re: Some black holes may actually be "Quark Stars"

Quark stars could fill the gap between the mass of neutron stars and stellar black holes - it is a pretty big gap. They would be very dim and difficult to detect.

3. Mar 19, 2010

### Naty1

Re: Some black holes may actually be "Quark Stars"

Interesting, thanks for the post.

I'd have more to say,maybe, but Chronos quote always distracts me (heh,heh)

Ok, I have regained what little composure I possess:

I don't know enough about quarks to comment...do they have a degeneracy pressure, like say electrons...
they are spin 1/2 particles so Pauli exclusion applies, right??? Electron degeneracy pressure is computed here,
http://en.wikipedia.org/wiki/Electron_degeneracy_pressure

so I guess somebody knows what it is for quarks and whether that fits the described "strange star" at all....??

4. Mar 22, 2010

### rhody

Re: Some black holes may actually be "Quark Stars"

Thanks for the responses:

I have a question, does current thinking/theory predict that deconfined quarks in the form of quark-gluon plasma exist in the core of Quark Stars ?

Rhody...

5. Mar 22, 2010

### SpiffyKavu

Re: Some black holes may actually be "Quark Stars"

We unfortunately have no way of knowing this. Our current theory does, in fact, allow such states to exist. Whether they represent reality, though, is another question.

Our current theory which rules in the high density matter inside a neutron star is quantum chromodynamics (QCD). As one ventures deeper into a neutron star, the pressure will change, as will the density and temperature. The way pressure behaves as density and temperature changes is called the equation of state. Different types of matter have different equations of state, and there have been a large number of proposed equations of state to predict how matter behaves at the extreme conditions of a neutron star.

Because a neutron star is held up by the nucleon-nucleon interaction pressure, this equation of state really affects the size of the neutron star. The mass, and the pressure behavior, also depend on the mass of the star.

Currently, our observations of the masses and radii of neutron stars have significant errors associated with the measurements. In fact, every proposed realistic equation of state cannot be ruled out with our observations, whether it be the equation of state that predicts quark stars, strange stars, less exotic neutron stars, or something different.

6. Mar 23, 2010

### stevebd1

Re: Some black holes may actually be "Quark Stars"

It's a bit old but this is an interesting article regarding phase transitions in neutron stars-

http://www.lbl.gov/Science-Articles/Archive/sb/Nov-2004/03-neutron-stars.html" [Broken]

and a couple of papers that look at quark deconfinement in neutron/strange stars-

http://arxiv.org/abs/0705.2708v2
Neutron Star Interiors and the Equation of State of Superdense Matter

http://arxiv.org/abs/astro-ph/0407155
Strange Quark Matter and Compact Stars

Last edited by a moderator: May 4, 2017
7. Mar 23, 2010

### rhody

Re: Some black holes may actually be "Quark Stars"

Thanks stevebd1,

Those links led me to this:http://www.lbl.gov/Science-Articles/Research-Review/Highlights/1998/PHYS_neutron.html#"

which suggests that from the article:

meaning if a spinning pulsar can be detected that for a short period increases its rotational frequency, that this may be a signature that in fact, quark-gluon plasma has been created in the interior of the neutron star.

BTW...

Do you happen to know if Dr Norman Glendenning is still alive or not ? I tried searching for an obituary for him and could find none (for free that is).

He had some predictions of the quark-gluon plasma that may be of interest to the BNL folks who are analyzing the RHIC data, and may be of interest to members of the LHC who are about to start colliding those 3.5TEV beams in a week or so.

Its funny, but whenever you are looking into something deeply, it always pays to conduct an extensive search for those who blazed a trail before you did. History repeats this over and over.

From the little I have read so far about Dr Glendenning, it appears he was ahead of his peers, only time and new discoveries will confirm that for sure, though.

Rhody...

Last edited by a moderator: May 4, 2017
8. Apr 4, 2010

### rhody

Re: Some black holes may actually be "Quark Stars"

stevebd1,

This is a good paper, thanks. Glendenning is sited 4 times in the references (192 of them!), it appears that there are about 7 models (see page 4), and that the core appears to be made up of up, down, and strange quarks, and exist in what is known as color superconducting state (see page 12, 3.5). On page 24, the author(s) pose a series of 25 conclusions/questions. It is obvious to me that a great deal of work needs to be done in order to come to grips with the conclusions/questions presented below:

Rhody...

9. Apr 6, 2010

### Orion1

interior charge function...

Can anyone here demonstrate how to graph the interior charge function of a charged neutron star?

Neutron star interior charge function: (ref.1 - pg. 20 - eq. 24)
$$Q(r) = 4 \pi \int_0^r j^0 e^{\frac{(\nu(r) + \lambda(r))}{2}} dr$$

I specifically do not know what the solution is for the electric current $$I$$ for the relativistic current density $$j^0$$.

Relativistic current density ???: (ref.1 - pg. 21 - eq. 34)
$$j^0 = \frac{I}{A_s} = \frac{dQ(r)}{dt} \frac{e^{\frac{(\nu(r) + \lambda(r))}{2}}}{4 \pi r^2}$$

$$I$$ - electric current
$$A_s$$ - sphere surface area

Reference:
http://arxiv.org/abs/0705.2708v2" [Broken]
http://en.wikipedia.org/wiki/Electric_current#Current_density"
http://en.wikipedia.org/wiki/Sphere#Surface_area_of_a_sphere"

Last edited by a moderator: May 4, 2017