Rocky Exoplanets Were Discovered Circling A Red Dwarf Six Billion Light-Years Away From Earth
A total of four small, rocky exoplanets were found circling Barnard’s Star, a red dwarf with a mass about one-sixth that of the sun. It is around six billion light-years away from Earth and is the fourth-closest star to our solar system.
The dwarf’s proximity makes it possible for future generations of humans to visit with advanced rocket propulsion technology. However, it is unlikely that any life will be detected there.
The four planets are each only about 20 to 30 percent the size of Earth. They orbit so close to their home star that they can zip around it in just a few days, suggesting that they are too hot for life to exist.
“It’s a really exciting find—Barnard’s Star is our cosmic neighbor, and yet we know so little about it,” said Ritvik Basant, the first author of the study and a Ph.D. student at the University of Chicago.
“It’s signaling a breakthrough with the precision of these new instruments from previous generations.”
Astronomers have been studying Barnard’s Star for centuries, hoping to find planets around it. It was first discovered in 1916 by E.E. Barnard at Yerkes Observatory.
It is the nearest star system that is most similar to our own. The star system that is the closest to us is Proxima Centauri, but it has three stars circling each other.
Barnard’s Star is what is known as an M dwarf star, which is abundant in the universe. So, scientists want to learn more about the kinds of planets they host. But these planets are too far away and too tiny to be observed with even the most powerful telescopes.
So, a team of scientists from the University of Chicago created and installed an instrument called MAROON-X. It is attached to the Gemini telescope situated on a mountaintop in Hawaii, which is specifically designed to search for distant planets.
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MAROON-X’s job is to see if the star appears to wobble back and forth. The wobbling effect is caused by the gravity of each planet tugging on the star.
MAROON-X measures the color of the light with accuracy so it can detect these minor movements and determine the number and masses of the planets circling the star.
The team analyzed data collected during 112 nights across a span of three years. They found evidence of three planets around Barnard’s Star.
After combining their findings with data from an instrument called ESPRESSO at the Very Large Telescope in Chile, they believed there was a fourth one as well. These planets are likely rocky planets instead of gas planets like Jupiter.
“We observed at different times of night on different days. They’re in Chile; we’re in Hawaii. Our teams didn’t coordinate with each other at all. That gives us a lot of assurance that these aren’t phantoms in the data,” said Basant.
The scientists hope that this latest discovery is the beginning of a new era of finding more planets in the universe. The new study was published in The Astrophysical Journal Letters.
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