Earth-size exoplanet found floating in Milky Way
New Delhi : The researchers have located an Earth-size exoplanet floating in Milky Way which is not orbiting any star.
It is not common to find such planets as most of the exoplanets discovered so far have been found orbiting a star.
However, theories of planet formation and evolution predict the existence of free-floating (rogue) planets, gravitationally unattached to any star.
Polish astronomers from the Astronomical Observatory of the University of Warsaw provided the first evidence for the existence of such planets in the Milky Way a few years ago.
In a latest, the researchers have located the smallest rogue planet in Milky Way.
"Our discovery demonstrates that low-mass free-floating planets can be detected and characterised using ground-based telescopes," said study co-author Andrzej Udalski, Professor at University of Warsaw in Poland.
Exoplanets can be only rarely directly observed. Usually, astronomers find planets using observations of the light from the planet’s host star.
For example, if a planet crosses in front of its parent star’s disk, then the observed brightness of the star periodically drops by a small amount causing so called transits.
Astronomers can also measure the motion of the star caused by the planet.
Free-floating planets emit virtually no radiation and — by definition — they do not orbit any host star, so they cannot be discovered using traditional methods of astrophysical detection.
Nevertheless, rogue planets can be spotted using an astronomical phenomenon called gravitational microlensing.