Evidence of baby planets found around young star

Tokyo

The data analysis related to a very young star named HL Tauri — estimated to be only about a million years old — has provided scientists firm evidence of baby planets around it.

The data collected by the Atacama Large Millimetre/submillimetre Array (ALMA) radio telescopes helped researchers uncover two gaps in the gas disk around HL Tauri.

Astronomers have not yet reached a definitive answer for what makes the gaps in the dust disk.

Because these disks are the sites of planet formation, some suggest that infant planets are the key.

The dark gaps are carved by planets forming in the disk that attract or sweep away the dust along their orbits, researchers said.

Others, however, doubt the planet explanation because HL Tauri is very young and studies indicate that it takes more than tens of millions of years for planets to form from small dust.

The team led by Hsi-Wei Yen at Academia Sinica Institute of Astronomy and Astrophysics in Taiwan and Shigehisa Takakuwa at Kagoshima University, Japan, focused on the distribution of gas in the disk to better understand the true nature of the disk.

If the dust gaps are caused by the variance of the dust properties, that wouldn't directly affect the gas, so no gaps would be seen in the gas distribution.

On the other hand, the gaps in the dust are caused by the gravity of forming planets, the gravity would be expected to created gaps in the gas as well.

Using ALMA's unprecedented sensitivity, the team yielded the sharpest image ever of the gas distribution around a young star.

The image revealed at least two gaps in the disk, at the radii of 28 and 69 astronomical units.

"To our surprise, these gaps in the gas overlap with the dust gaps. This supports the idea that the gaps are the footprints left by baby planets," said Yen in a paper appeared in the Astrophysical Journal Letters.

"Our results indicate that planets start to form much earlier than what we expected," Yen added.  — IANS