According to a study published on the arXiv database and expected to be published in the journal Nature Astronomy, the newly discovered brown dwarf has a temperature of around 7,730 degrees Celsius, while the surface temperature of the Sun is only about 5,500 degrees Celsius, as reported by Newsweek on June 20th. An international team of experts led by astrophysicist Na’ama Hallakoun from the Weizmann Institute of Science in Israel has named this celestial object WD0032-317B.
Illustration of a brown dwarf. Image: NASA’s Goddard Space Flight Center
Brown dwarfs are a type of celestial object that is half star, half planet, sometimes referred to as “failed stars.” They are giant gas balls typically with a mass ranging from 13 to 80 times that of Jupiter, still not massive enough to sustain the necessary nuclear fusion process and become a true star like the Sun.
Brown dwarfs are usually much cooler than WD0032-317B, making it the hottest recorded brown dwarf to date. Brown dwarfs typically have temperatures ranging from 480 to 1,930 degrees Celsius because their energy production is not as high as that of a true star. WD0032-317B has a mass ranging from 75 to 88 times that of Jupiter and orbits its host star in just 2.3 hours.
The unusual heat of WD0032-317B is due to its close proximity to the host star and its surface receiving a significant amount of ultraviolet radiation. This can lead to a process called thermal dissociation, causing the atmosphere of the celestial object to evaporate, with molecules being stripped away. Another example of a celestial object orbiting so closely to its host star that thermal dissociation occurs is KELT-9b, a gas giant exoplanet with a surface temperature of about 4,430 degrees Celsius on its dayside.
The research team hopes that this new discovery can help them understand the conditions on giant gas planets similar to Jupiter, such as KELT-9b, that orbit massive and super-hot stars. Observing these planets is challenging due to their close proximity to their host stars.