Low-Mass Normal-Matter Atmospheres of Strange Stars and Their Radiation

The quark surface of a strange star has a very low emissivity for X-ray photons. I find that a small amount of normal matter at the quark surface with temperature in the range 107 K ≲ TS ≪ mc2/k ≃ 6 × 109 K is enough to produce X-rays with high luminosity LX ≃ (1032-1034)[ΔM/(10-22 M☉)]2 ergs s-1. For a total atmospheric mass ΔM ~ 10-20 to 10-19 M☉, this luminosity may be as high as the Eddington limit. The mean energy of X-ray photons that are radiated from such a low-mass atmosphere of a strange star is ~102[TS/(108 K)]0.45, ≃30-300 times greater than the mean energy of X-ray photons that are radiated from the surface of both a neutron star and a strange star with a massive normal-matter envelope, ΔM ~ 10-5 M☉, for a fixed temperature at the stellar core. This raises the possibility that some black hole candidates with hard X-ray spectra are, in fact, such strange stars with a low-mass atmosphere. The X-ray emission from single strange stars is estimated.

[1]  A. Cherepashchuk.  REVIEWS OF TOPICAL PROBLEMS: Masses of black holes in binary stellar systems , 1996 .

[2]  C. Schaab,et al.  Thermal Evolution of Compact Stars , 1996, astro-ph/9603142.

[3]  A. Burrows,et al.  Pulsar recoil and gravitational radiation due to asymmetrical stellar collapse and explosion. , 1995, Physical review letters.

[4]  Cheng,et al.  Conversion of Neutron Stars to Strange Stars as a Possible Origin of gamma -Ray Bursts. , 1995, Physical review letters.

[5]  Dieter H. Hartmann,et al.  Models for classical gamma-ray bursts , 1995 .

[6]  D. Eichler,et al.  Baryon purity in cosmological gamma-ray bursts as a manifestation of event horizons , 1993 .

[7]  S. Woosley,et al.  The collapse of white dwarfs to neutron stars , 1992 .

[8]  F. Weber,et al.  Nuclear solid crust on rotating strange quark stars , 1992 .

[9]  R. Caldwell,et al.  Evidence against a strange ground state for baryons , 1991 .

[10]  P. Amsterdamski,et al.  Gamma-ray bursts from colliding strange stars , 1991 .

[11]  Madsen,et al.  Boiling of strange-quark matter. , 1991, Physical review. D, Particles and fields.

[12]  N. Glendenning.  Fast pulsars, strange stars; An opportunity in radio astronomy , 1990 .

[13]  L. Motz,et al.  The Structure and Evolution of Stars , 1989 .

[14]  K. Nomoto,et al.  Cooling of Neutron Stars: Effects of the Finite Time Scale of Thermal Conduction , 1987 .

[15]  E. Witten.  Cosmic separation of phases , 1984 .

[16]  P. Seymour.  Black Holes, White Dwarfs and Neutron Stars: The Physics of Compact Objects , 1984 .

[17]  E. H. Gudmundsson,et al.  Structure of neutron star envelopes , 1983 .

[18]  Saul A. Teukolsky,et al.  Black Holes, White Dwarfs, and Neutron Stars , 1983 .

[19]  T. Gaetz,et al.  Line radiation from a hot, optically thin plasma: collision strengths and emissivities , 1983 .

[20]  F. Dyson,et al.  Multiple Star Systems and X-Ray Sources , 1974 .

[21]  R. Latter,et al.  Electron Radiative Transitions in a Coulomb Field , 1961 .

[22]  D. E. Kerr.  Physics of Fully Ionized Gases. , 1956 .