Very hot and very dynamic atmosphere on a planet with no star nearby

In just a few hours of observing with the James Webb Space Telescope, astronomers have discovered a surprisingly dynamic atmosphere on a planet that, despite not having any nearby stars, is very hot.

The finding is the work of the international team of Brittany Miles, from the University of Arizona in the United States.

Cataloged as VHS 1256 b, the planet, located about 40 light-years from Earth, does not orbit around one star, but around two. It takes about 10,000 years to go around the couple completely. VHS 1256 b is about four times farther from its stars than Pluto is from our Sun.

Despite the distance of both stars, the upper part of its atmosphere reaches about 830 degrees Celsius.

Such a high temperature on a planet that is not close to any star is explained by the fact that it is a newly formed planet. The process by which a planet is formed carries a lot of heat and that is why very young planets are very hot. As time goes by, they get colder. VHS 1256 b, created about 150 million years ago, is still very young, unlike Earth at approximately 4.5 billion years.

In VHS 1256 b, atmospheric masses are constantly moving and mixing during a 22-hour shift, pulling warmer material up and pushing cooler material down. Silicate clouds also circulate. The resulting changes in brightness are so dramatic that it is the most variable brightness object of any known planetary mass to date.

Artist’s recreation of VHS 1256 b. In the distance, the pair of stars around which it revolves can be seen. (Image: NASA/ESA/CSA/Joseph Olmsted/STScI)

In data captured by the Webb Space Telescope, Miles and his colleagues also detected the presence of water, methane, and carbon monoxide remarkably clearly, and found traces of carbon dioxide.

What will become of this planet in billions of years? Being so far from its stars, it will cool over time and its skies could turn from cloudy to clear.

The James Webb Space Telescope (JWST) is the result of an international collaboration led by NASA, ESA and CSA, respectively the US, European and Canadian space agencies.

The study is titled “The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems II: A 1 to 20 Micron Spectrum of the Planetary-Mass Companion VHS 1256-1257 b.” And it has been published in the academic journal The Astrophysical Journal Letters. (Fountain: NCYT by Amazings)