Rings Form Around A Young Star: Are These Planets In The Making?

An international team of researchers discovered a young star with rings around it, hinting a planet formation.

Over the past years, there is a growing body of knowledge on the presence of exoplanets lurking in the solar system. Some scientists have seen much evidence of how these planets form, linking them to young stars. However, there are still many questions left unanswered.

Now, researchers at Rice University and their colleagues mapped gases in three distinct dark rings around a distant star for the first time. These rings mark where planets are believed to have formed from gas and dust around the star.

The new observations made with the Atacama Large Millimeter/submillimeter Array (ALMA) show that two newborn planets, each approximately the size of Saturn, are orbiting around a young star called HD 163296. The planets, which are not fully formed, unveiled themselves by the dual imprint they left in the dust and have portions of the star's disk.

According to Andrea Isella, lead author of the study and a Rice astronomer, he is sure that planets are responsible for clearing the outermost ones. However, the inner ring has far more carbon monoxide compared to the other two, making them speculate that there is no planet there.

The finding published in the journal Physical Review Letters  shows compelling evidence that there are two planets uniting far from the central star, and each potential planet is approximately the same mass as Saturn. "The inner gap is mysterious," Isella said in a press release by Rice University. "Whatever is creating the structure is removing the dust but there's still a lot of gas," he added.

The observations unveiled the presence of three distinct gaps in the star's protoplanetary disk. The first one is at about 60 astronomical units (AU) from the central star and the other two are 100 AU and 160 AU from the central star.

"Dust and gas behave very differently around young stars," Isella said in a statement released by the National Radio Astronomy Observatory (NRAO).

"We know, for example, that there are certain chemical and physical process that can produce ringed structures in the dust like the ones we have seen previously. We certainly believe these structures could be the work of a nascent planet plowing through the dust, but we simply can't rule out other possible explanations. Our new observations provide intriguing evidence that planets are indeed forming around this one young star," he added.

HD163296 is about 5 million years old and twice the mass of the Sun. It is located 400 lightyears away from Earth.