NASA’s Kepler space telescope has observed the effects of a dead star bending the light of its companion red star.The findings are among the first detections of this effect — a result predicted by Einstein’s theory of general relativity — in binary, or double, star systems.

The dead star, also called a white dwarf, is the burnt-out core of what used to be a star . It is locked in orbiting dance with its partner, a small “red dwarf” star. While the tiny white dwarf is physically smaller than the red dwarf, it is more massive. When the white dwarf passes in front of its star, its gravity caused the starlight to observably bend and brighten.

The  team used Cornell-led ultraviolet measurements of the star called  KOI-256 taken by the Galaxy Evolution Explorer (GALEX), a NASA space telescope operated by Caltech.

White Dwarfs

Where a star ends up at the end of its life depends on the mass it was born with. Stars that have a lot of mass may end their lives as black holes or neutron stars. A low and medium mass star (with mass less than about 8 times the mass of our Sun) will become a white dwarf. A typical white dwarf is about as massive as the Sun, yet only slightly bigger than the Earth. This makes white dwarfs one of the densest forms of matter, surpassed only by neutron stars.

Red Star A red dwarf /red star is a small and relatively cool star on the main sequence, either late K or M spectral type. Red dwarfs range in mass from a low of 0.075 solar masses (the upper limit for a brown dwarf) to about 50% of the Sun and have a surface temperature of less than 4,000 K.

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