Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download www.if.ufrgs.br
Document related concepts
Drake equation wikipedia , lookup
Observational astronomy wikipedia , lookup
Aquarius (constellation) wikipedia , lookup
Perseus (constellation) wikipedia , lookup
Cygnus (constellation) wikipedia , lookup
Star of Bethlehem wikipedia , lookup
Dyson sphere wikipedia , lookup
Corvus (constellation) wikipedia , lookup
Extraterrestrial life wikipedia , lookup
Space Interferometry Mission wikipedia , lookup
History of supernova observation wikipedia , lookup
Stellar evolution wikipedia , lookup
Type II supernova wikipedia , lookup
History of X-ray astronomy wikipedia , lookup
Crab Nebula wikipedia , lookup
Structure formation wikipedia , lookup
X-ray astronomy wikipedia , lookup
X-ray astronomy satellite wikipedia , lookup
X-ray astronomy detector wikipedia , lookup
Astronomical spectroscopy wikipedia , lookup
Timeline of astronomy wikipedia , lookup
Transcript
In this lecture we look at: 1) Neutron stars in x-ray binaries 2) Mass-radius relationship 3) Strange star candidates 4) Quark deconfinement at T=0 5) Astrophysical signals of quark matter Alfen radius RXJ 1856.5-3754 Drake et al. point out that this NS may in fact be a quark star (astro-ph/0204159) because of its small radius, which they argue is in the range between R' = 3.8 and 8.2 km!! ÄÄ Nasa press release of 10 April 2002: "Cosmic x-rays reveal evidence for new form of matter" WWW.msfc.nasa.gov/news Star's x-ray spectrum is well represented by a black body with a temperature of T'=7x105 K (X60 eV) The observed x-ray flux and temperature correspond to a stellar radius of R'= R (1-2M/R)-1/2 Y f (D/120 pc) km Drake et al.: R'=3.8 to 8.2 km Rotationally deformed, rotating neutron star Pulsar 3C58 " A 65 ms pulsar (J0205+6449) was discovered by Murray et al. (to appear in the ApJ, 2002). " This pulsar is at the center of 3C58, a young Crab-like supernova remnant (SN 1181). " Thus 3C58 is somewhat younger than Crab. " The pulsar's surface temperature is 1.12x106 K (Slane, Helfand, Murray, astro-ph/0204151, to appear in the ApJ) Nasa press release of 10 April 2002: "Cosmic x-rays reveal evidence for new form of matter" www.msfc.nasa.gov/news
