Astronomers using the «James Webb» telescope have obtained a unique image of the exoplanet 14 Herculis c, which turned out to be one of the coldest known.
It is noted that 14 Herculis c with a mass 7 times that of Jupiter is located 60 light years from Earth in the constellation Hercules. Using a powerful infrared camera (NIRCam) in the near-infrared, JWST took a rare photo one of the two planets, orbiting the star 14 Herculis, which is similar in age and temperature to our Sun, but slightly smaller and colder.
The planet 14 Herculis c has a surprisingly low surface temperature, only about -3 C°. Although astronomers about 6 thousand exoplanets were discovered. Only a small number of them could be directly photographed. The vast majority of them were extremely hot.
«The colder the exoplanet, the harder it is to detect. So this is a completely new mode of research, that Webb has discovered with its extraordinary sensitivity in the infrared range. We can now add to the catalog not only hot young exoplanets that have been photographed, but also older exoplanets that are much colder than we have seen before», — explains co-author and PhD student at Johns Hopkins University William Ballmer.
The second planet — 14 Herculis b is closer to the parent star. The orbits of the planets 14 Herculis b and 14 Herculis c are not in the same plane as the planets in our solar system. They intersect at an angle of 40°, forming something like the letter «X». The orbits of these planets are affected by the gravitational interaction between them.
According to astronomers, there are several versions of how the orbits of these planets could have shifted so much. One of the key hypotheses indicates that the orbital displacement of these planets occurred after the third planet was ejected from the system at an earlier stage of formation.
«The early evolution of our own solar system was determined by the motion and gravity of our gas giants. They scattered asteroids and rebuilt other planets. Here we see the consequences of a more violent planetary confrontation. It reminds us that something similar could have happened to our own solar system, and that the outcomes for small planets like Earth are often dictated by much larger forces», — William Ballmer notes.
With the help of JWST, astronomers have found that 14 Herculis c moves in an elongated elliptical orbit at a distance that is 15 times the distance of the Earth from the Sun. If you put this planet in the solar system, it would be somewhere between Saturn and Uranus.
The brightness of the planet measured at 4.4 microns, combined with its mass and the age of the system, indicates complex dynamics in the atmosphere. The brightness of 14 Herculis c at this wavelength was weaker than astronomers expected for a planet of similar mass and age.
«This exoplanet is so cold, that the best comparisons we have and that are well studied are the coldest brown dwarfs. In these objects, as in 14 Herculis c, we see carbon dioxide and carbon monoxide existing at temperatures where we should see methane. This is due to mixing in the atmosphere», — emphasized the co-author of the study Danielle S. Bardales Gagliuffi of Amherst College.
The study of 14 Herculis c is only the first step. Spectroscopic observations in the future will help to clarify the composition of the planet’s atmosphere and reveal the history of the formation of this unique system.
Source: SkiTechDaily
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