Massive stars prevent the formation of gas giants

#Massive #stars #prevent #formation #gas #giants

Massive stars hinder the formation of Jupiter-like planets, so-called gas giants. About 1,350 light-years from Earth, astronomers saw that massive stars ‘blow away’ gas from the dense disk of dust and gas surrounding a young, low-mass star with their emitted ultraviolet light. Gas giants need that gas to form.

The idea that massive stars push away gas around young stars with their UV light has existed for a long time. That followed from computer models. But now the phenomenon has been seen for the first time, astronomers wrote last week Science. The team of international researchers relied on observations from the James Webb space telescope (JWST) and the Atacama Large Millimeter Array (ALMA) high in the Chilean Andes.

Many bright, young stars are surrounded by a disk of gas and dust for several million years. By clumping together in a protoplanetary disk, planets slowly form. The formation of a gas giant (which consists mainly of gas) takes at least a million years.

But sometimes massive stars nearby ‘blow away’ the gas before gas giants have a chance to form. Young stars are often in a cluster together with massive stars. The ultraviolet or X-ray radiation from those massive stars can heat the gas in the protoplanetary disk. This causes the molecules in the gas to move faster and faster and eventually the gas escapes from the disk.

Orionnevel

Astronomers previously found indirect indications that this happens at d203-506, a protoplanetary disk in the Orion Nebula. But direct evidence is difficult to find, according to astronomer Alessandra Candian of the University of Amsterdam and author of the study. “Protoplanetary disks are small celestial objects compared to galaxies. In addition, the nearest star-forming regions, where we can find the disks, are far away from us.” The Orion Nebula, the closest star-forming region, is about 1,350 light-years from Earth.

By combining observations from JWST and ALMA, the astronomers were able to observe the disk d203-506 with enough detail to clearly see the escaping gas. JWST and ALMA each see in different light: JWST observes in infrared light and ALMA in radio waves.

When the astronomers calculated how much gas escaped from the disk, they saw that all the gas could disappear from the disk within a million years. That would mean that gas giants would not have a chance here.

Why did Jupiter, a gas giant in our solar system, form? Candian: “In the disk around the young sun – which eventually grew into our solar system – the radiation from nearby stars was not so strong. Enough gas remained for giant gaseous planets like Jupiter.”

Rare

Astronomer Nienke van der Marel from Leiden University, who was not involved in the research, finds the observations convincing. “It’s always really cool when we actually observe something that our models predict. I am curious whether the astronomers’ discovery is a coincidence, or whether this occurs in many places in the universe. We know that among low-mass stars – stars that have less than half the mass of the Sun – gas giants are rare. It would be interesting to see whether the places in the universe without gas giants are indeed near massive stars with strong UV radiation.”

Share Email the editor