Smallest known star

A star has to have a minimum mass in order to sustain the fusion of ordinary hydrogen into helium in its core and shine- if it is less than this amount, the object is called a brown dwarf. Astronomers believe this hydrogen burning limit is roughly 80 times the mass of Jupiter, or 7.6% the mass of the sun. The smallest star above this line is EBLM J0555-57Ab, which has a mass of 85 +/- 4 Jupiter masses, or 8.1% the mass of the sun, or 1.61103E29 kg. It is located in a triple star system roughly 600 light years from Earth, and is roughly the size of the planet Saturn.

However, several other candidates for the lowest mass star exist where their masses cannot be measured precisely enough to tell whether the object is a star, or a brown dwarf. It is hoped that the next generation of telescopes, such as the James Webb Space Telescope, will have sufficient sensitivity to better understand these smallest stars.