NASA's Kepler Telescope Discovers Dead Star Warping Light of Companion Red Star
Deep in space, a dead star is locked in an orbiting dance with a red star. Now, NASA's Kepler telescope discovered new evidence of the dead star bending the light of its companion. The findings are among the first detections of this effect, which was first predicted by Einstein's theory of general relativity.
The dead star is also called a white dwarf; it's essentially the burnt-out core of what used to be a star like our sun. The red star is a "red dwarf" star and while larger in size, it orbits the physically smaller white dwarf. Despite its small size, though, the dead star has a massive mass--enough to cause its companion's starlight to bend and brighten due to its gravity.
The red dwarf orbits the white dwarf in just 1.4 days, zipping around the dead star. In fact, the period is so short that the stars must have previously undergone a "common-envelope" phase in which the red dwarf orbited within the outer layers of the star that formed the white dwarf. This short orbital period also means that the red dwarf will soon expire. In a few billion years, the intense gravity from the dead star will strip material off of the red dwarf, forming a superheated accretion disk of in-falling material around the white dwarf.
In order to observe this effect, researchers used ultraviolent measurements of the star called KOI-256 that were taken by the Galaxy Evolution Explorer (GALEX), a NASA space telescope. The GALEX program actually measures ultraviolent activity in all of the stars in the Kepler field of view.
In the end, the researchers used gravitational lensing to determine the masses of the white dwarf and the red dwarf. In particular, they employed a technique called gravitational lensing. This method, which is based off of the notion that gravity bends light, has been used in the past to discover new planets and hunt for free-floating planets.
The findings are published in the Astrophysical Journal.
Want to see the dead star warping starlight? Check out the video below, courtesy of the California Institute of Technology.
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