The planets were discovered orbiting Barnard's Star, one of the closest stars to the Sun that has intrigued scientists since its discovery in 1916 by E.E. Barnard.
Astronomers have discovered four sub-Earth-mass planets orbiting Barnard's Star, the closest single star system to Earth. The discovery was made, among other things, using the Gemini North telescope, part of the Gemini International Observing System. Notably, one of the detected planets represents the lowest-mass planet ever detected using the ray velocity technique, setting a new standard for the detection of small planets in close proximity to stars.
For over a century, scientists have studied Barnard's Star in the hope of finding planets around it. First discovered by EE Barnard at Yerkes Laboratory in 1916, this star is the closest single star system to Earth. Barnard is a red dwarf—a low-mass star that often hosts compact planetary systems that include several rocky planets. Because red dwarfs are the most common type of star in the universe, understanding their surrounding planets is an important part of broad astronomical studies.
MAROON-X: A Continuous Precision Instrument for Discovering Planets Outside the Solar System
One of the key efforts in this search was led by Jacob Bean of the University of Chicago. His team developed MAROON-X, a highly sensitive instrument specifically designed to detect planets around red dwarf planets. The instrument is mounted on the Gemini North Telescope, which increases the observational capacity to detect small planets.
MAROON-X uses the beam velocity technique to detect planets – a method that detects the small motion of a star’s altitude due to the pull of planets in its orbit. This motion causes tiny changes in the wavelength of light emitted by the star. The precision of MAROON-X allows these changes to be measured in a way that allows the number and masses of planets orbiting the star to be determined, thereby confirming their existence with an extraordinary degree of precision.
Confirmation of the existence of planets: a scientific breakthrough
After meticulous calibration and analysis of data collected over 112 nights over a three-year period, the research team found solid evidence for the existence of three planets around Barnard's Star, two of which were originally considered candidates. The research team also combined data from MAROON-X with data collected in the 2024 survey using the ESPRESSO instrument on the European Astronomy Institute's Very Large Telescope in Chile, confirming the existence of a fourth planet, which has also moved from candidate to established planet.
“This is a truly exciting discovery – Barnard’s Star is our cosmic neighbor, yet we know so little about it,” says Ritwik Basant, a doctoral student at the University of Chicago and lead author of the paper to be published in The Astrophysical Journal Letters. “This marks a breakthrough in the accuracy of these new instruments compared to previous generations.”
For a century, scientists have studied Barnard’s Star in the hope of finding planets around it. First discovered by EE Barnard at Yerkes Laboratory in 1916, it is the closest single-star system to Earth. Now, using the Gemini North Telescope—one of the halves of the International Gemini Observatory, funded in part by the U.S. National Science Foundation and operated by NSF NOIRLab—astronomers have discovered four sub-Earth-mass planets orbiting this star. One of the planets has the lowest mass ever detected using the ray-velocity technique, setting a new standard for the discovery of small planets in close proximity to stars. Credit: International Gemini Observatory/NOIRLab/NSF/AURA/R. Proctor/J. Pollard
What do we know about these rocky worlds?
The planets discovered are likely rocky worlds, unlike gaseous planets like Jupiter. However, it will be difficult to determine this with certainty, since due to the angle of view from Earth, the stars do not pass in front of their host – a method used to determine the composition of planets. However, by comparing data with similar planets around other stars, it will be possible to make more precise estimates of their composition.
Using the data collected, the researchers were able to rule out, based on solid evidence, the existence of additional planets with a mass similar to that of Earth in the habitable zone of Barnard's Star – the region around a star where conditions allow for the existence of liquid, such as water, on the surface of a planet.
Barnard has been called the "Great White Whale" of planetary scientists; over the past century, several scientific groups have announced evidence of planets around it, only to have these later proven false. However, the latest findings provide much more confidence than previously believed.
“Our meetings were held at different times on separate nights and days. They are in Chile and we are in Hawaii. Our teams were not coordinated at all,” Basant notes. “This gives us great confidence that these are not imaginary appearances in the data.”
Revealing the smallest planets yet using new technology
The four planets, each about 20 to 30 percent the mass of Earth, orbit so closely around their host star that they complete their orbits in just a few days. The fourth planet is the lowest mass yet detected using the beam velocity technique. The team hopes that this discovery will mark the beginning of a new era in the discovery of sub-Earth-mass planets in the universe.
Many of the rocky planets discovered so far are more massive than Earth, and appear to be fairly similar across the Milky Way. However, there is reason to believe that small planets could have a more diverse composition. As scientists find more of these planets, they will be able to reveal more about how they formed and what conditions might be conducive to life.
The future of planetary exploration with MAROON-X
"The National Science Foundation is collaborating with the astronomical community on a journey deep into the universe to find planets with conditions that may resemble Earth," said Martin Steele, NSF program director for the International Gemini Observatory. "The planet discoveries made with MAROON-X, mounted on the Gemini North Telescope, are a significant step in that journey."
It should be emphasized that MAROON-X is still a guest instrument at the Gemini North Telescope. Given its excellent performance and popularity among the user community, it is currently in the process of transitioning to permanent status at the facility.
"This result demonstrates the competitive and advanced observing capabilities that the Gemini Telescope offers to its user community. The facility is in the midst of a major instrument upgrade, with MAROON-X being part of the first wave of new instruments, alongside GHOST at Gemini South and IGRINS-2 at Gemini North," notes Andreas Seyfarth, Director of Development at the International Gemini Observatory, who was part of the team that designed and built MAROON-X.
Comments
The closest star system to us, Proxima Centauri, consists of three stars orbiting each other, which changes the dynamics of planet formation and orbits, making it impossible for planets to form around it. Barnard's Star is next in line.
More of the topic in Hayadan:
2 תגובות
Red dwarfs cannot provide enough ultraviolet radiation to support life on the planet – from photosynthesis to vitamin D. When planets are found in the life-supporting zone of Alpha Centauri A – a system whose star is very similar to our Sun in terms of mass and age, then please wake me up. By the way, this system is only 4.37 light years from Earth. Sometimes you have to know how to look for what is right under your nose.
Red dwarfs don't emit enough ultraviolet radiation, which in turn fuels life - from photosynthesis to vitamin D. When they find a planet in the habitable zone of the Alpha Centauri A system, where its star is similar in mass and age to our Sun, then enlighten me. By the way, this system is only 4.37 light years from Earth... Sometimes you have to know how to look for what's right under your nose.