Astronomers have announced the discovery of a previously unknown exoplanet, which has been designated IRAS 04125+2902 b. The find is interesting because it is the youngest world found using the transit method.
Youngest exoplanet ever
IRAS 04125+2902 b orbits a protostar located in the Taurus molecular cloud. It is a region of active star formation 430 light-years from Earth, and is home to hundreds of newborn luminaries.
The proximity of the Taurus cloud makes it a very attractive target for astronomers. However, the situation is different in terms of how much they can learn about star formation, with exoplanets forming in their vicinity. The fact is that protostars are usually surrounded by clouds of debris. They do not allow astronomers to use the transit method to detect worlds in their vicinity.
But in the case of IRAS 04125+2902 b, astronomers got lucky. For some reason, the disk surrounding the protostar deformed, allowing the TESS space telescope to detect transits of the exoplanet. Its orbital period is 8.83 days and its diameter is about the same as Jupiter’s. Astronomers estimate that this world is only 3 million years old. Prior to this, researchers have not yet managed to find exoplanets younger than 10 million years using the transit method.
Subsequent radial velocity measurements showed that the exoplanet’s mass is no more than one-third that of Jupiter. This means it has a relatively low density and probably a bloated atmosphere. So this world is probably not a gas giant like Jupiter. Instead, it may well be a planet whose atmosphere is gradually shrinking. When it finally calms down, it could become a gaseous mini-Neptune or even a rocky super-Earth. These are the two most common types of planets in the Milky Way — despite neither of them being found in our Solar System.
Mystery of the warped disk
As for the reasons for the warping of the circumstellar disk, it remains a mystery to astronomers for now. They may be related to the migration of the exoplanet itself, which is approaching the star. Such a thing is possible if there is another massive object in this system — but astronomers have not found any trace of it yet.
It is true that the protostar has a distant stellar companion, which may also be the culprit behind the warping of the outer disk. However, the angle of inclination of its orbit coincides with that of the exoplanet and its parent star. Stars and planets tend to take the gravitational path of least resistance, so this arrangement conversely should push the disk to align more closely with the rest of the system, rather than such a radical deviation.
Another theory is that the disk could have been affected by the environment. The Taurus molecular cloud is a very busy place. Computer modeling has shown that the deformation of the disk may be caused by rains of falling material from the surrounding star-forming region. However, both modeling and observations have not answered the question of how often deformed disks occur in such regions.
Provided by NASA
