Category: star

nemfrog:

nemfrog:

Fig. 7. Cassiopeia, showing where a new star appeared in the year 1572. Flowers of the sky. 1879.

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astronomyblog: X-ray binary (black hole devou…

astronomyblog:

X-ray binary (black hole devouring a star)

X-ray binaries are a class of binary stars that are luminous in X-rays. The X-rays are produced by matter falling from one component, called the donor (usually a relatively normal star), to the other component, called the accretor, which is very compact: a neutron star or black hole. The infalling matter releases gravitational potential energy, up to several tenths of its rest mass, as X-rays. (Hydrogen fusion releases only about 0.7 percent of rest mass.) The lifetime and the mass-transfer rate in an X-ray binary depends on the evolutionary status of the donor star, the mass ratio between the stellar components, and their orbital separation.

An estimated 1041 positrons escape per second from a typical low-mass X-ray binary.

Proxima. Artist: David A. Hardy

Proxima. Artist: David A. Hardy

Photo

Photo