Astronomy and Astrophysics – Astrophysics
Scientific paper
1997-04-14
Astronomy and Astrophysics
Astrophysics
TeX, 35 pages including 6 postscript figures. To be published in ApJ
Scientific paper
10.1086/304937
The outermost layers of some neutron stars are likely to be dominated by hydrogen, as a result of fast gravitational settling of heavier elements. These layers directly mediate thermal radiation from the stars, and determine the characteristics of X-ray/EUV spectra. For a neutron star with surface temperature $T\lo 10^6$ K and magnetic field $B\go 10^{12}$ G, various forms of hydrogen can be present in the envelope, including atom, poly-molecules, and condensed metal. We study the physical properties of different hydrogen phases on the surface of a strongly magnetized neutron star for a wide range of field strength $B$ and surface temperature $T$. Depending on the values of $B$ and $T$, the outer envelope can be either in a nondegenerate gaseous phase or in a degenerate metallic phase. For $T\go 10^5$ K and moderately strong magnetic field, $B\lo 10^{13}$ G, the envelope is nondegenerate and the surface material gradually transforms into a degenerate Coulomb plasma as density increases. For higher field strength, $B>> 10^{13}$ G, there exists a first-order phase transition from the nondegenerate gaseous phase to the condensed metallic phase. The column density of saturated vapor above the metallic hydrogen decreases rapidly as the magnetic field increases or/and temperature decreases. Thus the thermal radiation can directly emerge from the degenerate metallic hydrogen surface. The characteristics of surface X-ray/EUV emission for different phases are discussed. A separate study concerning the possibility of magnetic field induced nuclear fusion of hydrogen on the neutron star surface is also presented.
Lai Dong
Salpeter Edwin E.
No associations
LandOfFree
Hydrogen Phases on the Surface of a Strongly Magnetized Neutron Star does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Hydrogen Phases on the Surface of a Strongly Magnetized Neutron Star, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydrogen Phases on the Surface of a Strongly Magnetized Neutron Star will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-489679