On some levels, the formation of stars and planets is simple: They are formed where there are more things. Thus, while the raw material for a star may be a diffuse gas cloud, the distribution of this gas is not completely uniform. Over time, the gravitational pull of areas that had somewhat more material will pull more and more material, eventually resulting in enough material to form a star. Or two – in many cases, more than one concentration of matter will form. In other cases, a single concentration will be split in two. Planets are also formed where matter is located, produced by the disk of material that feeds the star that forms. While this may be true in general, there are some problems with this. First, there is no clear dividing line between small stars such as brown dwarfs and the huge planets we have placed in a category called super-Jupiter. And the few planets we were able to visualize directly seem to be orbiting far from the star that hosts them, where there would not have to be much matter around to guide their formation. This week, astronomers announced the depiction of a super-Jupiter in the formation process, away from the star that appears to be orbiting. This suggests that the planet was probably formed through a process that usually produces stars and not through one that produces gas giants like Jupiter.

We were watching you

This star is called AB Aurigae, a very young star located about 500 light-years from the Sun. It is embedded in a cloud of gas, some of which is still likely to fall on the star. Outside is a cloud of dust. This cloud is thought to be a good candidate for planet formation for a number of reasons. First: The dust has been cleared from the area closest to the star. Second: The gas in the inner disk is formed into spiral arms by gravitational influences. Advertising
A team of researchers used the telescope to look for planets in AB Aurigae. And the researchers apparently found one, now called AB Aurigae b, in about 100 Astronomical Units from AB Aurigae (each AU is the standard distance between the Earth and the Sun). This is more than double the distance between the Sun and Pluto. This position places AB Aurigae b inside the dust ring and in a position where it should be able to create the kind of spiral arms seen in the gas between the dust and the star. This should also be far outside the area where the density of matter is high enough to accommodate normal planet formation. A look at the image files shows that we had indications that the planet was there for quite some time. The pictures clearly show that AB Aurigae b is in orbit. The researchers used modeling to determine what size planet could produce the light we have seen coming from AB Aurigae b. The models suggest that while the planet is still likely to grow, it already has at least four times the mass of Jupiter. An alternative approach to modeling suggests that it is likely to be nine times the mass of Jupiter. In both cases, the planet certainly fits into the category of super-Jupiter. The illustration also shows some fainter objects that are similar to AB Aurigae b, but even further away (430 and 580 AU). These may be extra planets, but we need additional observations to confirm this.

What is happening here?

So what’s going on here? Closer to a host star, gas giants are believed to form from the accumulation of a large rocky core which then begins to pump gas. This adds to the mass of the growing planet and further enhances its growth. This dramatic growth is interrupted because the gas that feeds it is eventually removed by the young star’s radiation. However, at the distances shown here, this process is unlikely to work. While more gas will have to stick longer, there is not enough high density material to build a large core. Dramatic development would never begin. Alternative is a process similar to creating a binary star system. Random fluctuations in the amount of material cause a concentration of matter that performs a similar function to the rock core. And because the formation site is so far away from the star, there is a chance that the growth process will continue further, creating a super-Jupiter. Nature Astronomy, 2022. DOI: 10.1038 / s41550-022-01634-x (About DOIs).