A new planet is born!
Only months ago, Steph Sallum and Kate Follette were working on independent research projects when something suddenly brought them together: they were both observing a very special star.
This star, LkCa15, located about 450 light years away from Earth, is distinctive because of a rotating disk of dense gas that surrounds it, making it the perfect birthplace for a planet. Scientists suspect that planets form inside protoplanetary disks such as this one by sweeping up and accumulating dust and debris, which creates a gap in which they can reside.
Scientists have been studying exoplanets — planets orbiting a star other than our own — for many years, but only 10 have ever been photographed. Even more fascinating is that this is the first time that pictures are being taken of one during its formation.
In a statement, Follette said: “No one has successfully and unambiguously detected a forming planet before. There have always been alternate explanations, but in this case we’ve taken a direct picture, and it’s hard to dispute that.”
Image shows a composite where blue represents the MagAO data taken at H-alpha, and green and red show the LBT data taken at Ks and L' bands. The greyscale is a previously published millimeter image of the disk. Photo credit: Stephanie Sallum, University of Arizona
Researchers are only just beginning to make this kind of observation, thanks to instruments like the world’s largest telescope, the Large Binocular Telescope (LBT) located in Arizona, as well as the UA’s Magellan Telescope with its Adaptive Optics System (MagAO), located in Chile.
Pictures were originally taken using the LBT and its novel image-sharpening technique. But, distant planets are particularly hard to photograph because of the mixing of hot and cold air that causes atmospheric turbulence and makes stars shimmer. This is where MagAO came in to independently corroborate the discovery.
Follette explained that cosmic objects get extremely hot as they form and glow deep red because of their hydrogen composition. Both the planet and the star emitted this particular wavelength of red light. “We were able to separate the light of the faint planet from the light of the much brighter star and to see that they were both growing and glowing in this very distinct shade of red," she said.
University of Sydney's Professor Peter Tuthill who co-authored on the paper published today in Nature said: "It's fantastic to see these cutting-edge instruments now enabling us to make such exciting discoveries."
When Follette first made the discovery, she didn’t want to assume anything too quickly: "I was pretty excited as soon as I processed the data, but I wanted to be cautious, I was pretty sure I had found something interesting, but in this field we're always chasing objects that are just at the edge of what we can detect. The really cool thing is that it survived all of our tests to make sure it was real."
She is hopeful that this research could help us to better understand how exoplanets form and whether our own solar system formed in a unique manner.
Watch the video below to see some of the first images of the birth of an alien planet: