These days, researchers commonly discover exoplanets, or planets outside our solar system. But sometimes there’s a special discovery, like an exoplanet right in our backyard — and that’s the case with a recent finding showing that our nearest stellar neighbor, Barnard’s Star, hosts up to four exoplanets.
It’s most common for scientists to discover planets which are large and which orbit close to their bright stars, because these are most visible using exoplanet detection methods. But Barnard’s Star is different — it’s a common type of cool, low-mass planet called a red dwarf. Red dwarfs are very numerous in our galaxy, so scientists are interested in the kinds of planets that they can host as they could be a good location to look for evidence of life.
The recent findings up the number of exoplanets orbiting Barnard’s Star from one to at least three, possibly four, as researchers were able to use the MAROON-X instrument on the Gemini North telescope to confirm the existence of planets that were previously only candidates.
“It’s a really exciting find — Barnard’s Star is our cosmic neighbor, and yet we know so little about it,” said lead author Ritvik Basan of the University of Chicago in a statement. “It’s signaling a breakthrough with the precision of these new instruments from previous generations.”
Previously, Barnard’s Star has been considered the “great white whale” for exoplanet hunters because although it is nearby to us, at just six light-years away, the fact it is so small and dim makes it difficult to be certain about the presence of exoplanets. In this case, two different groups of researchers using different instruments both found indications of exoplanets, making them confident that they exist there.
“We observed at different times of night on different days. They’re in Chile; we’re in Hawai‘i. Our teams didn’t coordinate with each other at all,” said Basant. “That gives us a lot of assurance that these aren’t phantoms in the data.”
The four planets likely hosted by Barnard’s Star are tiny, at just 20 to 30% of the mass of Earth, and orbit extremely close to the star so that a year there lasts just a few Earth days. It’s also harder for researchers to spot such tiny planets compared to big gas giants which are much more visible in their effects.
“The U.S. National Science Foundation is collaborating with the astronomy community on an adventure to look deeper into the Universe to detect planets with environments that might resemble Earth’s,” says Martin Still, NSF program director for the International Gemini Observatory. “The planet discoveries provided by MAROON-X mounted on Gemini North provide a significant step along that journey.”
The research is published in The Astrophysical Journal Letters.
