This Giant Exoplanet Is Forming in a Very Strange Way, Astronomers Say

The discovery of a gas giant exoplanet in the process of forming could change our understanding of planet formation.

The planet is forming at a large distance from its star, and is coming together in a strange way.

Evidence suggests that the planet is forming through a top-down collapse of clouds of gas, rather than the more commonly accepted bottom-up model.

The idea that there are multiple pathways for planet formation is supported by this.

In the last few years, AB Aurigae has been studied intensely. It is a very young star, no more than 5 million years old, and the Sun is 4.5 billion years old.

The star is surrounded by a disk of gas and dust. This gas and dust is what feeds the growth of a young star. It is an excellent laboratory for studying planetary system formation because it is so close to the star.

The planets, asteroids, dwarf planets, comets, and other rocks will be formed from what is left over of that disk. Smaller objects can form planets in the core accretion model according to our current understanding of planet formation.

In this model, pieces of rock in the disk of dust and gas stick together, first via gravity and then via electrostatic forces, forming a larger and larger body. The exoplanet has a solid core, which makes it relatively cool and dim.

The disk instability model is the other model for planet formation. The cooling disk causes instabilities and breaks apart when formed this way. Part of the disk collapses into a gas giant. The exoplanet has no solid core and forms hotter and brighter.

It has been difficult to tease out what is happening in the disk ofAB Aurigae.

Astronomers thought they saw an exoplanet similar to Neptune. Astronomers said the object could be a second star.

A team of scientists used the Hubble Space Telescope and the National Astronomical Observatory of Japan's Subaru Telescope to take more detailed observations of a star.

The observations show a clump and other features in the disk that are consistent with the formation of an exoplanet, not at Neptune's distance from the Sun, but over three times farther.

The spiral arm features we observed in this disk are what we should expect if we have a planet with a mass of Jupiter or more.

A massive planet should perturb them like we are seeing here.

The amount of rock in the disk would not be enough to form a planet. The baby exoplanet is nine times the mass of Jupiter, according to the calculations by the team. The disk instability model is the most likely formation pathway, according to the researchers.

Currie says that nature can produce planets in a range of different ways.

The team found features in the disk at distances of 430 and 580 astronomical units and suggested that exoplanets might be forming there too.

The findings shed some new light on the processes involved in planet formation, and could help us better understand our own Solar System.

Future studies of theAB Aurigae system using more powerful instruments may allow us to explore the evolution of our own little corner of the galaxy.

This new discovery is strong evidence that some gas giant planets can form by the disk instability mechanism, says Alan Boss of the Carnegie Institution of Science, who did not participate in the research.

The leftovers of the star-formation process will end up being pulled together by gravity to form planets, one way or the other.

Nature Astronomy has published the research.