A team of scientists is going to hunt for planets around our nearest stars, in the continuing search for worlds on our doorstep that can be studied in great detail.
The project is called Red Dots, led by Guillem Anglada-Escudé from Queen Mary University of London. This same team was responsible for the Pale Red Dot campaign, which last year found the planet Proxima b around our nearest star, Proxima Centauri, 4.2 light-years away.
Now they are focusing their attention on two other stars, Barnard’s Star and Ross 154, in addition to continuing to observe Proxima Centauri. The former is 6 light-years from Earth and the latter is 9.7 light-years.
Using the European Southern Observatory’s (ESO) High Accuracy Radial velocity Planet Searcher (HARPS) in Chile, and other telescopes around the world, the team will observe the stars for about 100 nights. On June 15, scientists began photometric studies of the stars to model stellar activity. Today, they have begun spectrographic observations, looking for the noticeable wobble of planets.
All three of the stars are red dwarfs, or M-dwarfs, stars that are much smaller and dimmer than our Sun. These types of stars have become prime targets for planet hunters of late, as any exoplanets in orbit tend be easier to see and in smaller observable orbits than those around Sun-like stars.
“Red Dots is a more longer term initiative to make deep surveys for planets around all the M-dwarfs within 5 parsecs (16 light-years) from the Sun,” Anglada-Escudé told IFLScience, noting there are 40 such stars in this distance range. Proxima Centauri is the closest, Barnard’s star the second closest, and Ross 154 the eighth. These stars have been picked as they are visible by HARPS during the observing campaign.
While Proxima Centauri is known to have one planet so far, scientists think there might be others there too. Almost all stars in our galaxy are thought to have one or more planets in orbit, and red dwarfs are by far the most common type of star, making up three quarters of those in the Milky Way.
It will take a long time to analyze the data from this project, so we might not hear about any planets for up to a year, after any results have been peer reviewed. But judging by the success of the Red Dots campaign, there are grounds for cautious optimism.
If any planets are found, they could also be the subject of further study. Upcoming telescopes like the ESO’s Extremely Large Telescope, which should come online in 2024, could directly image some of these planets and work out what sort of atmosphere they have, if any.
“We will be releasing all the data on Proxima as soon as it comes down from the telescope,” said Anglada-Escudé. “I also hope that some of my colleagues (or at least enthusiastic PhDs and postdocs) will take the opportunity to look into the data.”
There has been a lot of debate about whether red dwarf planets can be habitable. These stars are prone to more flaring events than Sun-like stars, and as the planets orbit so close it’s thought their atmospheres might be blown away over time. This is still an open area of research.
But finding nearby worlds, habitable or not, is a key goal for planet hunters. And there’s even a chance we might visit a world like Proxima b via the Breakthrough Starshot project, on which the ESO is a partner. Finding other nearby planets like this would be a welcome boon.