CHRISTCHURCH, NEW ZEALAND — Astronomers from the University of Canterbury in New Zealand have discovered a new "super-Earth" orbiting a star located in or near the edge of the Milky Way's "galactic bulge," a dense region of stars in the center of our galaxy, according to a press release published by the university on May 11.
This rare super-Earth is 25,000 light-years away. It is one of only a handful among the 4,000 exoplanets to have been detected that is similar to Earth in both size and orbit.
According to their research, which was published on May 7 in The Astronomical Journal, the world is four times the mass of Earth.
It orbits a dim dwarf star that is only 10 percent the mass of our Sun. This star is so small that the researchers could not determine if it is a low-mass star or a kind of failed star called a brown dwarf.
The newly discovered orbits its star at a distance between those of Venus and Earth around our Sun. But because its star's mass is so small, a year on this world lasts 617 days.
To find the planet, the researchers used a method called gravitational microlensing.
"The combined gravity of the planet and its host star caused the light from a more distant background star to be magnified in a particular way. We used telescopes distributed around the world to measure the light-bending effect," University of Canterbury astronomer Antonio Herrera Martin, said in the news release.
"These experiments detect around 3,000 microlensing events each year, the majority of which are due to lensing by single stars," the paper's co-author Michael Albrow was quoted as saying in the news release.
"Dr Herrera Martin first noticed that there was an unusual shape to the light output from this event, and undertook months of computational analysis that resulted in the conclusion that this event was due to a star with a low-mass planet."
