Neither a planet nor a star: a strange space object found that is hotter than the Sun
The object WD0032-317B, orbiting a distant star 1,400 light-years away from Earth, has been found to be the hottest of its kind. Its existence contradicts scientists' ideas about what is possible in the Universe.
The discovery was reported by an international team of astrophysicists in an article published in the journal Nature Astronomy. WD0032-317B is a brown dwarf. Objects of this category are in an interesting state - not quite a planet, but not a star either. With about 13 times the mass of Jupiter, such an object can have enough pressure and heat in its core to trigger fusion of deuterium.
Brown dwarfs can reach sizes of about 80 Jupiter masses and temperatures of about 2,227 degrees Celsius. They are colder and dimmer than red dwarfs, but glow in the infrared.
Dwarfs are known to be the last stage of life for stars like the Sun, which eject their outer layers before dying, and their core is compressed into an ultra-dense object about the size of the Earth.
Interestingly, this object is actually a hellscape. Because its orbit passes close to a very hot star, the average surface temperature exceeds 7,727 degrees Celsius. This is significantly hotter than the outer temperature of our Sun (5,499 degrees Celsius) and hot enough to cause all molecules in the atmosphere to be torn apart into their component atoms.
Scientists know that it is quite natural for brown dwarfs to be hotter than ordinary planets, but this is the first time that such an object has reached the temperature of the Sun. Usually, brown dwarfs cannot even reach the temperatures of red dwarfs, whose maximum temperature is 3,727 degrees Celsius.
It is known that planets that are very close to their stars are irradiated by a huge amount of ultraviolet light, which can lead to the evaporation of their atmospheres, as well as to thermal dissociation, a process during which molecules are broken into atoms.
The object itself is orbiting a very hot, low-mass white dwarf star, WD0032-317, which has a mass of about 40% of the Sun's mass and burns at a temperature of about 36,726 degrees Celsius. It makes one revolution around the star in 2.3 hours.
One side of the brown dwarf is constantly facing the star, while the other side remains in constant night. The scientists calculated the temperatures on the surface of the object and were surprised by the data obtained.
It turned out that, depending on the model of the white dwarf's nucleus used, the temperature of the heated day side of the satellite varies between 6,977 and 9,527 degrees Celsius. The temperature of the night side varies between 1,027 and 2,727 degrees Celsius.
No other known planet or brown dwarf is hotter, making WD0032-317B not only extremely surprising, but also an excellent candidate for studying how extremely hot stars can vaporise their lower-mass companions.
The discovery of this object, scientists hope, will also help them better understand what happens to Jupiter-like gas giants in the vicinity of extremely hot massive stars. Scientists cannot observe such planets directly, as the dawn distorts the data.
Earlier, OBOZREVATEL also reported that astronomers have discovered the "Scary Barbie" - a powerful and impressive object that has never been seen before.