This artist’s concept shows the planet KOI-5Ab moving over the face of a Sun-like star, which is part of a three-star system located 1,800 light-years away from the star. -bhad Cygnus. Credit: Caltech / R. Hurt (IPAC)
Shortly after NASA’s Kepler mission began operations back in 2009, the space telescope saw what was thought to be a planet about half the size of Saturn in a multi-star system. KOI-5Ab was just the second planetary candidate found by the mission, and inspiring as it was at the time, it was sidelined as Kepler solved more and more planetary missions.
By the end of the spacecraft’s work in 2018, Kepler had discovered 2,394 exoplanets, or planets erupting stars outside our solar system, and an additional 2,366 exoplanet candidates still needing confirmation.
“KOI-5Ab was abandoned because it was complex, and we had thousands of candidates,” said David Ciardi, a senior scientist at NASA’s Exoplanet Science Institute. “Choosing was easier than KOI-5Ab, and we were learning something new from Kepler every day, so that KOI-5 would be largely forgotten. ”
Now, after a long and long hunt and many telescopes, Ciardi said he has “resurrected KOI-5Ab from the dead.” Thanks to new ideas from NASA’s second planetary hunting mission, the Transiting Exoplanet Survey Satellite, or TESS, and several ground-based telescopes, Ciardi was finally able to decipher and prove all the evidence surrounding KOI-5Ab that he was there. There are interesting details about crossing it.
Our solar system seems to have a gas giant planet like Jupiter or Saturn due to its size, KOI-5Ab is unusual in that it moves a star in a system with two other companion stars, orbiting a plane is out of alignment with at least one of the stars. The arrangement raises the question of how each member of this system formed out of the same moving clouds of gas and dust. Ciardi, based at Caltech in Pasadena, California, presented the findings at a landmark meeting of the Astronomical Society of America.
Building the trail
After it was first discovered by Kepler, Ciardi and other researchers built the route on KOI-5Ab as part of a chest of planetary candidates they were pursuing. Using data from the WM Keck Observatory in Hawaii, the Palomar Caltech Observatory near San Diego, and Gemini North in Hawaii, Ciardi and other astronomers determined that KOI-5b appeared to orbit a single star in a system three-star. However, it was not yet possible for them to determine whether the planet’s signal was an erroneous signal from one of the other two stars, or, if the planet was real, which stars it was changing.
Then, in 2018, TESS came forward. Like Kepler, TESS is looking to emit a star light that comes when a planet orbits in front of it, or moves over a star. TESS saw a portion of Kepler’s field of view, including the KOI-5 system. Certainly, TESS also identified KOI-5Ab as a candidate planet, although TESS calls TOI-1241b. As Kepler had previously seen, TESS discovered that the planet erupts its star about every five days.
“I was thinking to myself, ‘I remember this target,'” Ciardi said, after seeing the TESS data. “But we have not yet been able to determine for sure whether the planet was real or whether the blip in the data came from another star in the system – it could be the fourth star. ”
Ears in the wobbles
He then went back and reviewed all the data, and then found new advertisements from ground-based telescopes. Applying another technique to Kepler and TESS, the Keck Observatory is often used for continuous investigations of exoplanets by measuring the small motion of a star as a planet orbits and takes its place. -out gravity thatching. Ciardi, working with other scientists through an exoplanet collaboration group called California Planet Research, looked for any shifts in Keck’s data on the KOI-5 system. They could look out for a wobble made by the inner companion star circling the primary star from a similar planetary motion as it moves around the main star. Together, the different collections of data from space-based and ground-based telescopes helped to prove that KOI-5Ab is, in fact, a planet orbiting the main star.
“Bingo – it was there! If it weren’t for TESS looking at the planet again, I would never have gone back and done this detective work, ”he said. It’s a lot of slippage within data collected from many different telescopes to finally go down this planet. ”
KOI-5Ab moves to Star A star, which has a relatively close companion, Star B. Star A and Star B orbit each other every 30 years. The third gravitationally connected star, Star C, moves stars A and B every 400 years.
The KOI-5 star system consists of three stars, with labels A, B, and C in this diagram. Stars A and B orbit each other every 30 years. Stars C move stars A and B every 400 years. The system hosts one known planet, called KOI-5Ab, which has been discovered and identified using data from NASA Kepler and TESS (Transiting Exoplanet Survey Satellite) missions, as well as ground-based telescopes on the ground. KOI-5Ab is about half the mass of Saturn and star orbit A about every five days. Its orbit is titled 50 degrees compared to the plane of stars A and B. Astronomers suspect that this false orbit was caused by a star B, which suddenly kicked the planet as it developed, it leaked out of orbit and caused it to migrate inward. Credit: Caltech / R. Hurt (IPAC)
Orbit skewed
The combined data set also reveals that the planet’s orbital plane is not aligned with the orbital plane of Star B, the second inner star as would be expected if all the stars and planet were on the planet. formed from the same disc of swirling material. Astronomers are not sure what caused the KOI-5Ab mismatch but believe that the planet’s second star suddenly exploded during its development, slipping its orbit and causing no migration. i in. Triple star systems make up about 10% of all star systems.
This is not the first evidence of planets in double and triple star systems. One interesting case involves the GW Orionis three-part star system, in which a disk in the shape of a planet is torn into special, unmarked rings, where planets could form. But despite the discovery of planets in a multi-star system, far fewer planets have been observed than in single-star systems. This could be due to observational bias (it is easier to find single-star planets), or because planetary formation is indeed so common in multi-star systems.
“This research underlines the importance of NASA’s full fleet of space telescopes and their collaboration with ground-based systems,” said Jessie Dotson, project scientist for the Kepler space telescope at NASA’s Ames Research Center in Silicon Valley in California. ” Look like this one. it is long. ”
New and future instruments, such as Palomar’s Radial Velocity Palomar Instrument at Palomar’s Hale Telescope, NASA’s NEID instrument and National Science Foundation in southern Arizona, and the Keck Planet Finder will open new avenues for learning about exoplanets.
Contact the media:
Elizabeth Landau
NASA Headquarters, Washington
202-923-0167
[email protected]
Alison Hawkes
NASA Ames Research Center, Silicon Valley, Calif.
650-604-4789
[email protected]