Birth Of Jupiter-like Planet Watched By Astronomers

Astronomers at the Very Large Telescope in Chile, using a high-resolution infrared camera, have confirmed that a young gas planet, presumed to be similar to Jupiter in our own solar system, is orbiting the star designated HD 100546.

A relatively close 335 light years away, HD 100546 is one of our close cosmic neighbors. Its age of five to ten million years also makes it relatively young in astronomical terms.

Not unlike many young stars, it is surrounded by a massive disk of gas and dust.

The outer regions of the disk are home to the protoplanet, which lies at a distance from its parent star that is some fifty times greater than the distance between the Earth and the Sun.

The team first proposed the existence of this young planet in a research paper published in 2013. At that time the researchers were still debating another possible explanation for the data they had collected, whether the observed object might be a more massive and older giant planet that had formed further inside the circumstellar disk before being hurled outward.

“It’s a scenario we still can’t rule out completely,” says ETH Zurich’s Sascha Quanz, who led the team. “But it’s much less likely than our explanation, which suggests that what we’re seeing is the birth of a planet.”

Named HD 100546 b, the planet is the first object of its type to be discovered.

“It provides us with unique observational data on what happens when a gas giant is formed,” Quanz says.

Scientists have previously investigated how, where and when giant planets form in the disks surrounding young stars only in theory or using computer simulations. “Now we have a kind of ‘laboratory’ that can give us empirical data,” Quanz explains.

Besides the parent star’s circumstellar disk, there may also be a smaller, circumplanetary disk encircling the newly formed planet from where matter is accreted onto the planet.

“Our object still seems to be surrounded by a lot of dust and gas,” Quanz says.

Future observations using the Alma radio telescope in Chile’s Atacama Desert should be able to confirm if the protoplanet is in fact surrounded by its own disk, as well as provide indications regarding the disk’s mass and size.

The Very Large Telescope is part of the European Southern Observatory on Paranal Mountain.

Aascha P. Quanz, Adam Amara, Michael R. Meyer, Julien H. Girard, Matthew A. Kenworthy, and Markus Kasper
ApJ 807 64 doi:10.1088/0004-637X/807/1/64