A new study by astronomers from the Center for Astrophysics proves that there is a new planet in the neighborhood. Planets are formed in protoplanetary disks, which are belts of gas and dust that surround newly formed young stars. Although the universe has hundreds of these disks, it has been challenging to observe actual planetary birth and evolution in these environments .Astronomers have developed a new method to find these elusive newborn planets, along with “smoking gun” evidence of a small Neptune- or Saturn-like planet hidden in the disk. The Astrophysical Journal Letters published a description of the findings today.
According to Feng Long, a postdoctoral scholar at the Center for Astrophysics and project leader, “finding young planets directly is very difficult and has only been effective in one or two situations so far.” Because they are enveloped by a significant amount of gas and dust, the planets are always too faint to be seen. Instead, they must look for signs that a planet is forming beneath the dust. Long notes that in recent years, “many structures have appeared in the disks that we think are due to the existence of the planet, but it could also be due to something else.” “We need new methods to explore and provide evidence that a planet exists.”
For her research, Long decided to revisit the protoplanetary disk LkCa 15. The disk is located in the constellation Taurus, 518 light-years away. Previous research using images from the ALMA observatory showed that a planet was forming in the disk. I spent a long time digging through fresh high-resolution ALMA data on LkCa 15, mostly from 2019, and found two faint features that weren’t there before.
Long found a dusty ring with two distinct, glowing clumps of material orbiting it at a distance of about 42 AU from the star, 42 times the distance between Earth and the Sun. The material was split 120 degrees and looked like a small cluster and a larger arc. He had long used computer simulations to analyze the situation and determine what was accumulating the material. He found that the sizes and locations of the objects were consistent with the presence of a planet. He explains, “This arc and the cluster are separated by about 120 degrees.” This degree of disparity is significant mathematically; it doesn’t just happen.The findings suggest the planet is between one and three million years old and as large as Neptune or Saturn.