An itty-bitty star, with a radius about the size of Saturn’s, is one of the smallest ever found.
Known as EBLM J0555-57Ab, the star is significantly smaller than the Jupiter-sized TRAPPIST-1, a peewee star famous for hosting a septet of Earth-sized planets. And it’s comparable in size to a previously reported runt, 2MASS J0523-1403.
Although the star’s girth is similar to Saturn’s, it is much heftier, at almost 300 times Saturn’s mass. Still, that’s only about 8 percent of the sun’s mass, meaning that the star barely meets the qualifications for joining the stellar ranks, scientists report July 12 in Astronomy & Astrophysics. The star is just at the limit at which nuclear fusion can occur in a stellar core. If the star were less massive, it would instead be a failed star known as a brown dwarf.
The miniature star orbits another, larger star. Scientists with the Wide Angle Search for Planets, or WASP, collaboration detected the star with a method typically used to scout out exoplanets, watching it pass in front of its companion and dim the larger star’s light.