An object orbiting a star 1,400 light-years away seriously challenges our notions of what is possible in the universe. It’s a brown dwarf, a strange category of object between planets and stars, but it orbits so close to its very hot host star that its temperature exceeds an incredible 8,000 Kelvin (7,727 degrees Celsius or 13,940 degrees Fahrenheit) – hot enough. splitting the molecules in the atmosphere into their complex atoms.

This is much higher than the Sun’s surface temperature, which reaches a relatively pleasant 5,778 Kelvin. In fact, this brown dwarf is a temperature record holder – the hottest object of its kind we’ve ever found.

Although brown dwarfs are generally hotter than planets, they burn cooler than the coldest red dwarf stars – they have absolutely no way of reaching Sun-like temperatures in their fusion engines.

An international team led by astrophysicist Naama Hallakoon of the Weizmann Institute of Science in Israel named the object WD0032-317B.

The team says the discovery could help us understand what happens to Jupiter-like gas giants orbiting extremely hot, massive stars, which can be difficult to observe due to properties such as stellar activity and rotational speed. Planets orbiting close to their stars are irradiated with large amounts of ultraviolet light. This can cause their atmosphere to evaporate and break down the molecules within, a process known as thermal decomposition.

However, we don’t know much about this extreme environment. At such close proximity to a very bright star, it can be difficult to distinguish signals from an orbiting exoplanet from stellar activity.

We know of an exoplanet hot enough for thermal weathering. This KELT-9b orbits a blue supergiant star that heats the exoplanet’s day side to temperatures in excess of 4,600 Kelvin (4,327 degrees Celsius or 7,820 degrees Fahrenheit).

This is hotter than most stars – red dwarfs, the most common stars in the galaxy, have a maximum surface temperature of about 4,000 Kelvin.

However, one way to study these extreme regimes could be brown dwarfs in white dwarf binaries. White dwarfs are much, much smaller than blue supergiants like KELT-9, making them dimmer and making it easier to detect signals from overheated satellites.

A brown dwarf isn’t exactly a planet, but it’s not exactly a star either. A planet-like object with a mass of about 13 times that of Jupiter could have enough pressure and heat in its core to ignite deuterium fusion. It is a “heavy” isotope of hydrogen; The temperature and pressure required for its synthesis are much lower than the temperature and pressure required for the synthesis of ordinary hydrogen burning in the cores of stars.

Brown dwarfs can reach about 80 Jupiter masses and temperatures of about 2500 Kelvin. They are cooler and dimmer than red dwarfs, but glow in the infrared wavelength range.

White dwarfs, on the other hand, are the last stage of the life of stars like the Sun. When hydrogen runs out in a star’s core, it sheds its outer layers, and the core, no longer supported by the external pressure of fusion, collapses into a superdense object the size of Earth.

White dwarfs glow from residual heat, but the death process is very energetic – they are extremely hot, their temperature comparable to that of blue supergiants. This brings us to WD0032-317, a very hot, low-mass white dwarf star. It is about 40 percent of the mass of the sun and burns at a temperature of about 37,000 Kelvin.

In the early 2000s, data from the Ultra-Violet-Visual Echelle Spectrograph (UVES) instrument on the European Southern Observatory’s Very Large Telescope suggested that WD0032-317 was lurking around, dragging an unseen orbital companion in place. Later near-infrared observations revealed that this moon is a brown dwarf.

Hallakow and colleagues used UVES to obtain new observations of the star and found that the companion is a brown dwarf with a mass of 75 to 88 Jupiter in a separation orbit of only 2.3 hours.

The smoking weapon that led to the discovery was a kind of smoking star. When the brown dwarf’s daytime face is turned towards us, astronomers can detect the hydrogen it released as the star vaporized it.

Because the brown dwarf and the star are so close together, the brown dwarf is tidally locked. This means that one side – the day side – permanently turns to the star, while the other remains constantly at night. The team calculated the extreme temperatures, and the numbers are impressive.

“Depending on the white dwarf core model used, the companion’s heated day-side temperature ranges from ≈7250 to 9800 Kelvin – as hot as an A-type star – night-side temperature ranges from ≈1300 to 3000 Kelvin, or a temperature difference of ≈6000 K – KELT-9b About four times more than in ‘,” they write in their article.

“The nighttime temperature range covers T to M dwarfs. The ‘equilibrium’ blackbody temperature (intrinsic luminosity and albedo is neglected and assumed to be in thermal equilibrium with external radiation) of an irradiated companion is about 5100 Kelvin, hotter than any known giant planet and ≈1000 Kelvin hotter than KELT-9b, resulting in ≈5600 times the extreme ultraviolet flux.’

No known planet or brown dwarf is hotter, making WD0032-317B not only extremely remarkable, but an excellent candidate for studying how extremely hot stars evaporate their less massive companions. Researchers say studying objects like WD0032-317B could help us understand rare extraterrestrial objects like KELT-9b.