quark stars aka strange stars

[CPL.Luke]

http://www.cerncourier.com/main/article/42/5/10

 

any thoughts

 

I was also wondering how can any neutron star still be considered a star? it would seem that al fusion would have stopped if it was truly composed of neutrons.

[Martin]

The second part of your post, CPL

 

 

...I was also wondering how can any neutron star still be considered a star? it would seem that al fusion would have stopped if it was truly composed of neutrons.

 

it might still go on shining for millions of years because it is so hot

 

massive things take a while to cool

 

you are raising a point about words:

if something is as massive as a star

and is hot and shining as a star

 

then can you still call it a star, even if it is no

longer fusing elements in its core and generating energy that way

 

 

also what about gravitational energy, some stars continue generating energy because they continue to contract (convert gravitational energy to heat) even when they are no longer able to do nuclear fusion.

would you say that counts?

 

 

finally, when a neutron star cools down so it no longer glows, what do you call it? a dead star?

 

nature always eludes the net of language

[Martin]

Hey CPL,

your link was to a short article in Cern Courier and it mentioned

the name Slane and the year 2002

 

So I went to ARXIV search engine and put in Slane

and 2002

and got this

 

http://arxiv.org/abs/astro-ph/0204151

 

 

the article also mentioned Yakolev,

why dont you go to arxiv.org and search Yakolev

 

the scholarly journal article will usually have a lot more and clearer info

than the short press release

[Martin]

Hey CPL,

if you go to that Slane link I just posted

it will have a CITED BY thing to click

that finds you all the later papers which referenced this Slane paper

 

In other words, it is a way of getting more recent papers about the same thing.

 

I clicked the Cited By thing and got this

 

http://arxiv.org/abs/astro-ph/0305249

 

it looks cool.

it is called

 

Strange Quark Matter in Neutron Stars? - New Results from Chandra and XMM

Authors: Markus H. Thoma, Joachim Truemper, Vadim Burwitz

 

notice that these neutron stars are so hot (millions of degrees) that they shine with Xray light (as well as UV visible and infrared)

the sun is only a few thousand degrees so it shines with mostly just

infrared and visible and a little UV

hotter things shine with more energetic light

 

notice that the results are from the Chandra and XMM space telescopes

because these are Xray telescopes (not visible light)

 

congratulations for finding the original CernCourier lead, it led to some good stuff on arxiv.

 

someone should do a search with Yakolev and see if more comes up

[Martin]

I tried "CITED BY" on that last one and got a couple of papers that

are actually recent, like October 2004.

 

 

http://arxiv.org/abs/astro-ph/0410407

 

http://arxiv.org/abs/astro-ph/0407155

 

these are really good

 

they summarize all the stuff that has been figured out about

these supercompact stars since the 2002 papers that your CernCourier

report noted.

 

it is a really big deal

 

there might be particles which are more fundamental than quarks

and they are called "preons"

so if you squeeze iron hard enough you get neutron matter

and if you squeeze neutrons hard enough you get quarks

and then if you keep on squeezing you get "preons"

 

and maybe by observing compact stars astronomers will be able

to get evidence of this

 

and again it looks like astronomy/astrophysics is advancing and scouting ahead of

the huge accelerators and colliders that they have to build

to get ever higher energies, astronomy seems to be guiding the search

(providing ideas like dark matter and dark energy, too)

 

I wonder what Severian thinks. he does accelerator particle-physics, and he posts here sometimes. hav yu met?