It was not that long ago the prospect of finding planets outside of our solar system was a huge discovery. At the present, astronomers are probing outside of the Milky Way to find exoplanets elsewhere. A group of researchers at the University of Oklahoma have revealed the presence of a large number of free-floating planets in a galaxy 3.8 billion light-years away. The process by which this was made a reality is known as gravitational lensing.
Particularly large objects in space like the black hole in the center of the have tendencies of bending the light as they pass. From the vantage point of the earth, this would look like a lens that can be modified in order to study exoplanets that are quite far in greater detail than would have been possible previously.
Quasar Microlensing to find Exoplanets
In this scenario, the beams of a quasar assisted researchers to detect the presence of large bodies within a galaxy lying between the earth and the source of light. While looking at the light emitted by the lensed quasar RXJ1131-1231 with the Chandra X-Ray Observatory, researchers noticed a wavelength of light emitted was stronger than anything which could be explained solely by the lensing effect of stars within the intervening galaxy.
After modeling the results, researchers concluded the shift of the energy signature was probably caused by a large population of exoplanets ranging from Jupiter to the moon. The model matching the data found a ratio of 2,000 exoplanets for every main sequence star within the galaxy. These planets seem to be wandering freely without a star to orbit in close proximity.
Because these models also only gave a wide range of potential planet masses, researchers hope to identify the distribution concerning the sizes a bit further with additional construction on the modeling. Xinyu Dai, the lead author of the paper and researcher at the University of Oklahoma claimed they thought there are some signatures illustrating the presence of a small mass type of population, however, there is a need to run detailed modeling in order to ascertain whether it is, in fact, true or not.
This is not the first time though microlensing uncovered an interesting object. In 2014, an alignment between two stars revealed the presence of an exo-moon. According to astronomers, the system known as MOA-2011-BLG-262 can either be a star, moon or planet. It is unfortunate though as astronomers cannot do follow up observations and confirm if the object existed, the micro-lensing originated from a chance encounter involving two stars which will not be repeated. However, if it was an exo-moon, then it was the first one to be discovered.
David Bennett from the University of Notre Dame stated they would not have a chance to observe the candidate again but there is a chance of getting unexpected finds like this one. Finding exoplanets that are nearby which originated abroad could assist in allowing the scientific community to learn about the way exoplanets develop and whether there are differences between the planets born within different galaxies.