Evidence of a small planet in the process of formation more than 500 light-years away


Astronomers agree that planets are born in protoplanetary disks – rings of dust and gas that surround newborn stars, RT reports.

While hundreds of these discs have been observed throughout the universe, monitoring the birth and formation of actual planets within these environments has proven difficult.

Now, astronomers at the Center for Astrophysics at Harvard and Smithsonian University have developed a new way to discover these elusive baby planets — and with them, evidence of a small Neptune or Saturn-like planet lurking in a disk.

The results of this study were published in full in The Astrophysical Journal Letters.

“Direct detection of minor planets is very difficult and has so far only been successful in one or two cases,” says Fang Long, a postdoctoral fellow at the Center for Astrophysics, who led the new study. Because it is embedded in thick layers of gas and dust.”

Instead, scientists must look for evidence to conclude that a planet is developing under dust. To study it, Long decided to re-examine a protoplanetary disk known as LkCa 15.

The disk is located 518 light-years away in the constellation Taurus in the sky. Scientists have previously reported evidence of planet formation in the disk using observations with the ALMA observatory.

Scientists have long examined the new, high-resolution “ALMA” data about LkCa 15, which the observatory obtained mainly in 2019, and discovered two hidden features that had not been discovered before.

About 42 astronomical units from the star, or 42 times the distance the Earth is from the sun, he discovered long ago a dusty ring with two separate, bright groups of matter circling within it. The material took the form of a small block and a larger arc, and was separated by 120 degrees.

Scientists have long studied the scenario using computer models to find out why the material accumulated and learned that its size and locations matched the model for the existence of a planet.

They said, “This arc and the lump are about 120 degrees apart. And this degree of separation doesn’t just happen, it’s mathematically significant.”

Long points to locations in space known as Lagrange points, where two moving objects — such as a star and an orbiting planet — produce enhanced attractions around them where matter may accumulate.

“We see that this material not only floats freely, but that it is stable and has a preference for where you want to locate it based on the physics and things involved,” Long explains.

In this case, the arc and the long-discovered agglomeration are located at the L4 and L5 Lagrangian points. And hidden at a position 60 degrees between them, a small planet causes dust to accumulate at points L4 and L5.

The results show that the planet is about the size of Neptune or Saturn, and its age is about one to three million years, and this is relatively small when it comes to planets.

Direct imaging of the young, newborn planet may not be possible any time soon due to technology limitations, but Long believes that more “alma” observations of LkCa 15 could provide additional evidence to support her planetary discovery.

Long also hopes that her new method of planet-finding – with material accumulating preferentially at Lagrange points – will be used by astronomers in the future.

“I hope this method will be widely adopted in the future, the only caveat is that this requires very deep data because the signal is weak,” she says.

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