A new object assumed to be a high-mass giant planet or a low-mass brown dwarf has been discovered by astronomers using a gravitational microlensing technique. These findings of the substellar host of a host star system designated MOA-2012-BLG-006L were presented in a paper that was published last April 4, 2017, on the arXiv pre-print server.
According to Phys.org, the new findings were obtained after the discovery of the microlensing event MOA-2012-BLG-006 that was announced on February 9, 2012, by the Microlensing Observations in Astrophysics group. The event was then again detected by the Optical Gravitational Lensing Experiment a few days later and was labeled as OGLE-2012-BLG-0022. All the succeeding observations from these events that reveal a signal in the binary system were labeled as MOA-2012-BLG-006L and OGLE-2012-BLG-0022L.
Microlensing is the only method known capable of discovering planets at truly great distances from the Earth. Per Planetary.org, this method can find planets orbiting the stars near the center of the galaxy thousands of light-years away unlike, radial velocity searches that can only look for planets in our immediate galactic neighborhood hundreds of light-years away from Earth.
The origin of microlensing method dates back at the time of Albert Einstein. "When the light emanating from a star passes very close to another star, the gravity of the intermediary star will slightly bend the light rays from the source star causing the two stars to appear farther apart as they normally would - astronomical effect from the Theory of Relativity," Einstein said.
The latest analysis of the microlensing available data of MOA-2012-BLG-006L was provided by the 1.3m telescope at Las Campanas Chile, the 1.8m telescope at Mt. John Observatory in New Zealand and Keck-II telescope in Hawaii, gives more clues about the properties of the system's components. Likewise, new results indicating that the substellar companion in MOA-2012-BLG-006L is a massive giant planet or a brown dwarf star has been recently presented by a team of researchers led by Radoslaw Poleski of the Warsaw University Observatory in Poland.
Aside from MOA-2012-BLG-006L, the team also discovered MOA-2012-BLG-006Lb, a substellar companion of the MOA-2012-BLG-006L. Using the microlensing method, this object is about 8.4 times more massive than Jupiter, while its host has approximately half the mass of the sun.
"We presented a discovery of MOA-2012-BLG-006Lb - an object a few times larger than Jupiter, which can be classified based on its mass either as a planet or a brown dwarf..." the researchers explains in their study. "Hence, the lower mass object could have formed independently, and thus resembles brown dwarfs even if its mass is smaller than the commonly assumed boundary."
Based on the study, the researchers concluded that their discovery will bring more knowledge to the mechanisms responsible for the formation of objects in space such as the MOA-2012-BLG-006L. Likewise, through the data they gathered using microlensing, the researchers further explain that these objects seem to operate similarly in their solar neighborhood and in more distant parts of the Milky Way galaxy.
