Scientists have spotted what appears to be evidence of a planet forming near a young star. And they’ve got pictures.
The star is AB Aurigae. It’s 520 light-years away in the constellation Auriga. (Auriga is Latin for “the chariot driver,” which the constellation is supposed to depict.) At just 4 million years old, AB Aurigae is about one-thousandth the age of our sun. “It’s really a baby,” Emmanuel Di Folco says. He works at the University of Bordeaux in France. As an astrophysicist, he studies the interactions of mass and energy within the cosmos.
Astronomers have seen gaps and large-scale spirals around young stars before. They thought these must have been created by unseen exoplanets — planets outside of our solar system.
Developing planets pull in material from nearby space. In the process, their motions twist the gas around them like swirling skirts. Scientists can hunt for these swirls to pinpoint a planet’s location.
Di Folco and his colleagues used observations from two telescopes in Chile: the Atacama Large Millimeter/submillimeter Array and the Very Large Telescope. These scout for infrared light — a type the human eye can’t see. Images from the telescopes show a spiral disk of gas and dust surrounding AB Aurigae. Near the spiral’s center was a small S-shaped twist.
That twist “is the precise spot where a new planet must be forming,” says Di Folco. He and his colleagues described their find May 20 in Astronomy & Astrophysics. “It was amazing,” Di Folco says. “It was exactly as we were expecting.”
The apparent planet’s mass is not known. It did make very big waves in the disk of gas. That means it probably has to be a gas giant like Jupiter rather than a rocky planet like Earth. And it might not be alone. The researchers detected a hint of a second planet near the disk’s outer edge.