According to a new scientific study, one of our solar system’s nearest cosmic neighbors, Alpha Centauri is home to a great number of mini-Earth’s, while it lacks the existence of Giant planets.
“The universe has shown us that the most common types of planets are small ones, and our study reveals that they are most likely to orbit Alpha Centauri A and B,” said Debra Fischer, professor of the University of Yale and expert in exoplanets.
Professor Fisher has been searching for Earth-like planets for decades.
The Alfa Centauri system has three stars: Centauri A, Centauri B, and Proxima Centauri. Last year’s discovery of an Earth-like planet that orbits the Proxima Centauri star triggered a new wave of scientific and general interest about this system.
Because Alpha Centauri is relatively close to Earth, about 4.37 light years away (41.3 billion kilometers), it is “our first stop outside the solar system,” Fischer said. “It is virtually certain that there are small, rocky planets around Alpha Centauri A and B”.
The findings are based on data from a new wave of more advanced spectrographic instruments installed in Chile: Chiron, a spectrograph built by Fischer’s team; Harps, built by a team from Geneva; and Uves, as part of the Very Large Telescope Array (VLT) project.
The first author of the research and Yale graduate, Lily Zhao, determined that Alpha Centauri A most likely has planets orbiting it that are smaller than 50 Earth masses. She determined the Alpha Centauri B most likely has planets smaller than 8 Earth masses, while Proxima Centauri has planets smaller than half Earth mass.
In addition, the study eliminated the existence of a number of larger planets, which, Zhao said, removed the possibility of planets close to the size of Jupiter generating asteroids that hit or change the orbits of small planets similar to Earth.
“This is a very green study in that it recycles existing data to draw new conclusions,’ said first author Lily Zhao. By using the data in a different way, we are able to rule out large planets that could endanger small, habitable worlds and narrow down the search area for future investigations.”
Featured image: The two bright stars are (left) Alpha Centauri and (right) Beta Centauri. The faint red star in the center of the red circle is Proxima Centauri.