By Mia Becker-Hansen | Contributor
Astronomers may have glimpsed what appears to be a previously unknown planet circling one of the closest stars to Earth.
Alpha Centauri is the closest star system to the Earth at 4.37 light years (25 trillion miles) away, which is considered very local in cosmic terms. It is made up of three stars, two of which (Alpha Centauri A and B) form a binary star system that orbit around a common centre point. These two stars appear to the naked eye as a single star in our night sky.
The international team observed the star as a part of the “New Earths in the Alpha Centauri Region” experiment run by Breakthrough Watch. The experiment aims to locate and study Earth-sized rocky planets around Alpha Centauri and other local stars. Chief engineer of the Breakthrough Initiatives, Pete Klupar, said “we detected something. It could be an artefact in the machine, or it could be a planet, or it could be asteroids or dust”.
The scientists were using a new coronagraph on the Very Large Telescope instrument. It aided in the search by blocking out the light from Alpha Centauri, which makes it easier to spot any orbiting planets. Klupar describes the instrument as being similar to blotting out the Sun with a thumb at arm’s reach on the Earth. “We’re trying to see a flashlight right next to a lighthouse,” he said. It allows for extraordinary sensitivity to directly image planets beyond those of our Solar System.
If proven to be a planet after further investigations, the sighting would be the first to directly image an exoplanet around a nearby star.
“A lot of people say planets can’t form in this kind of binary and that’s one reason we are cautious about claiming it is actually a planet. But if it is, it would be about the size of Neptune,” Klupar added.
The planet would lie in the stars habitable zone, also known as the ‘goldilocks zone’, where the temperatures would allow liquid water to form, and would take about a decade to complete an orbit.
Professor Beth Biller, who studies exoplanets at the Institute of Astronomy at Edinburgh University, said the researchers had an “interesting candidate”, but are right to be cautious.
“It will require a separate, independent detection to really confirm this one,” she said. “If confirmed, it could be a detection of the dust disc around the star or an actual planet. Both would be very interesting outcomes.”
Klupar said the team want another look at the planet later in the year to see if it has moved to the location it is predicted to be in at the time. This could further confirm its identity as an exoplanet. However, new observations may not be possible soon with the coronavirus pandemic still going on.
This discovery could be very exciting news if it is indeed a new planet, it remains ambiguous for now but scientific observation will continue. Hopefully the pandemic will not hinder observations, if it does then the potential planet may remain shrouded in mystery for longer than scientists expect.