For the first time,
astronomers may have seen direct evidence of a planet forming around a young
A spiral disk of gas and
dust surrounding the star AB Aurigae contains a small S-shaped twist near the spiral’s
center, infrared telescope images show.
That twist “is the precise
spot where a new planet must be forming,” says astrophysicist Emmanuel Di Folco
of the University of Bordeaux in France.
Previously, astronomers have
seen gaps (SN:
11/6/14) and large-scale spirals (SN: 6/14/18) that are thought to be created by unseen planets
in disks of gas and dust around young stars. Theories of how planets coalesce and gather material from these
disks predict that planets’ motions
would further twist the gas around them like swirling skirts, pinpointing a
planet’s location (SN: 5/11/18).
Now, Di Folco and colleagues
have used infrared observations from the Atacama Large Millimeter/submillimeter
Array and the Very Large Telescope, both in Chile, to find a spiral and zero in on one such S-shaped twist around AB Aurigae. The team describes its findings in
the May Astronomy & Astrophysics.
“It was amazing,” Di Folco
says. “It was exactly as we were expecting from the theoretical predictions of
The star, about 520
light-years away in the constellation Auriga, is just 4 million years old, about
one one-thousandths of the age of the sun. “It’s really a baby,” Di Folco says.
The potential planet’s exact mass is not known, but it probably would have to be a gas giant like Jupiter rather than a rocky planet like Earth to make such big waves in the disk. And it might not be alone — there’s a hint of another planet near the disk’s outer edge.