View text source at Wikipedia
![]() Artistic representation of a rogue planet. | |
Discovery | |
---|---|
Discovery date | 2020 |
Microlensing[1] | |
Physical characteristics | |
Mass | 0.3 or 2 M🜨[1] |
OGLE-2016-BLG-1928 is an exoplanet located in the constellation Sagittarius, discovered via gravitational microlensing.[2][a] It is likely to be a rogue (free-floating) planet, as no host star was detected within 8 astronomical units.[1]
This likely free-floating planet has a mass of either 0.3 ME, if it is located within the galactic disk, or 2 M🜨 is located in the galactic bulge. The former scenario is the most likely.[1] Low-mass rogue planets like OGLE-2016-BLG-1928 are thought to be very common in the Milky Way, but few have been spotted as they are very hard to detect.[3] It is believed that these planets have been ejected from their origin planetary systems.[4]
OGLE-2016-BLG-1928 was discovered through a gravitational microlensing event observed by the Optical Gravitational Lensing Experiment (OGLE) and Korea Microlensing Telescope Network (KMT-N) surveys. This event had the shorest duration of any observed, at just 41.5 minutes. The discovery was announced in 2020 by a team of astronomers led by P. Mroz.[1] A microlensing event happens when the observer, the planet and a background star are aligned: The planet's gravitational effect magnifies, distorts and creates multiple images of the background star.[4]
Microlensing is an useful method for detecting planets that emit little or no radiation.[4]