A planet-like object hotter than the sun has been discovered by an international team of astronomers. Their paper was accepted for publication in Nature Astronomy and is now available on the arXiv pre-print server.
Brown dwarfs are sometimes known as failed stars since they do not fit into either the planet or star categories. Researchers have discovered one that orbits a star so near that its temperature is hotter than our sun.
The brown dwarf was discovered orbiting a low-mass white dwarf dubbed WD0032-317, which has 40% the mass of our sun but is hotter, with a temperature of roughly 37,000 Kelvin (the sun’s surface temperature is approximately 5,778 Kelvin). The brown dwarf was renamed WD0032-317B, and its temperature was discovered to be around 8,000 Kelvin, substantially hotter than typical brown dwarfs due to its close closeness to the star.
A team reviewing data from the European Southern Observatory’s Very Large Telescope discovered WD0032-317 in early 2000. Researchers noticed something tugging on the star, implying it had a companion. The new team discovered that it was a brown dwarf, not a companion star. It has a mass of 75 to 88 Jupiters and orbits its star quickly, with a period of about 2.3 hours.
They also mention that the brown dwarf is tidally locked, resulting in heated temperatures on one side (about 7,250 to 9,800 Kelvin) and lower temperatures on the other (around 1,300 to 3,000 Kelvin). The hot side has temperatures that are approximately 5,100 Kelvin hotter than any other known large planet. That makes WD0032-317B the hottest known brown dwarf, as well as the hottest known planet. According to the researchers, this could reveal information about how hot stars cause companion objects to vaporize.
