Astrophysicists have reported finding for the first time a group of planets in another galaxy, outside the Milky Way. The breakthrough was made using microlensing.
Microlensing
The phenomenon involves astronomical objects such as a star or a galaxy in the foreground that causes the light from an object in the background to bend.
Microlensing makes it possible for astronomers to find otherwise invisible objects in the background such as a planet, when it passes across the bent light from the background object.
Scientists take advantage of this phenomenon to discover planets located too far away from Earth. The use of microlensing is currently the best method to find objects that are too far from Earth to be detected by telescopes.
One of the most distant exoplanet ever discovered, which lies nearly 13,000 light years away from Earth was discovered through microlensing. To date, more than 50 planets have been found using this method. Microlensing can also yield estimates of an extraterrestrial object's mass and its distance from its host star.
Researchers also want to tap on this method to find more black holes.
First Time Discovery Of Planets Outside Of Milky Way Galaxy
Now, researchers said that the method has helped them detect the presence of objects in extragatic galaxies. Microlensing has helped scientists find exoplanets in the Milky Way galaxy but until this new discovery, astronomers has found no evidence of planets in other galaxies.
The masses of the newly detected entities range from those comparable to that of the moon to those of Jupiter's.
"These small planets are the best candidate for the signature we observed in this study using the microlensing technique," study researcher Xinyu Dai, from the College of Arts and Sciences of the University of Oklahoma, said.
The researchers found the planets in a galaxy located 3.8 billion years away. At such distance, it is not possible to observe these planets directly. Researchers said that analysis of extragalactic microlensing using data from the NASA Chandra X-ray Observatory allowed them to detect the presence of these planets and even get an idea about how massive they are.
"Quasar microlensing provides a means to probe extragalactic planets in the lens galaxy, by studying the microlensing properties of emission close to the event horizon of the supermassive black hole of the background quasar, using the current generation telescopes," the researchers wrote in their study, which was published in Astrophysical Journal Letters.
