The Hubble Space Telescope is getting its first look at a planet beyond our solar system, a mystery of astronomy for more than two decades.
The so-called exoplanet, officially named HD 116899Ab, lies about 42 light-years away in the constellation Aquarius. If you could look up at the star in the constellation, you would probably see the small, faint planet passing in front of the star, its starlight emitted by the star momentarily scattered by the planet’s light and travelling out to space.
HD 116899Ab. NASA
HD 116899Ab. NASA
HD 116899Ab. NASA
“This is our first big planet to orbit the star and allow us to study it,” Chris Landolf, associate principal investigator of the Hubble at the California Institute of Technology in Pasadena, said in a news release. “If we look back at the very beginning of astronomy, when the first classically designed instruments were being used, this was the first time that something like this was observed.”
The planet is still very far away and does not appear much brighter than the faint star. What makes it remarkable, however, is the fact that the planet has been spotted and confirmed using the same instrument that has hunted for astronomers’ answer to what brought us here, the Hubble Space Telescope.
HD 116899Ab. NASA
HD 116899Ab. NASA
“The discoveries presented at the American Astronomical Society in March confirmed once and for all that Hubble was absolutely unique in its ability to document and detect planets,” Irina Krasnova, co-author on the Hubble paper and a postdoc in astrophysics at the Harvard-Smithsonian Center for Astrophysics, said in the release. “The ability to observe exotic and remote worlds with this perspective has finally given astronomers an opportunity to study objects we never expected to see. Thanks to Hubble and the [WISE] Wide Field Planetary Camera 2, we discovered a new type of planet for the first time. And with the upcoming Kepler Mission, we may even find other exoplanets with even better eyes.”
The new discoveries come during the current phase of Hubble’s primary mission, which was to characterize the distant, faraway universe using the telescope. In 2017, astronomers from Caltech and the Harvard-Smithsonian Center for Astrophysics measured HD 116899Ab using the WISE Wide Field Planetary Camera 2. When NASA launched the Hubble Space Telescope in 1990, the telescope was tasked with uncovering the composition and chemical composition of the universe, but on that day it had no chance of finding a distant, distant planet to study.
The result of that early mission was that the results looked like something from a popular science story, like a prequel to The Hitchhiker’s Guide to the Galaxy.
This latest finding marks the earliest detection of a planet outside our solar system to make it into the public record. The previous record was held by HD 106849b, found by the Kepler spacecraft, which pointed at one out of one thousand stars and found a planet orbiting a star located about 6,500 light-years away in the constellation Arp 267.