A rogueplanet, also termed a free-floating planet (FFP) or an isolated planetary-mass object (iPMO), is an interstellar object of planetary mass which is not gravitationally bound to any star or brown dwarf.
Gravitational microlensing is an astronomical phenomenon caused by the gravitational lens effect. It can be used to detect objects that range from the mass of a planet to the mass of a star, regardless of the light they emit. Typically, astronomers can only detect bright objects that emit much light (stars) or large objects that block background light. These objects make up only a minor portion of the mass of a galaxy. Microlensing allows the study of objects that emit little or no light.
The Optical Gravitational Lensing Experiment (OGLE) is a Polish astronomical project based at the University of Warsaw that runs a long-term variability sky survey (1992–present). The main goals are the detection and classification of variable stars, discovery of microlensing events, dwarf novae, and studies of the structure of the Galaxy and the Magellanic Clouds. Since the project began in 1992, it has discovered a multitude of extrasolar planets, together with the first planet discovered using the transit method (OGLE-TR-56b) and gravitational microlensing. The project has been led by professor Andrzej Udalski since its inception.
OGLE-2005-BLG-071L is a distant, magnitude 19.5 galactic bulge star located in the constellation Scorpius, approximately 11,000 light years away from the Solar System. The star is probably a red dwarf with a mass 43% of that of the Sun.
OGLE-2007-BLG-349(AB)b is a circumbinary extrasolar planet about 8,000 light-years away in the constellation of Sagittarius. It is the first circumbinary exoplanet to be discovered using the microlensing method of detecting exoplanets.
OGLE-2017-BLG-1522Lb is an exoplanet thought to be orbiting a brown dwarf. It was discovered by KMTNet and the OGLE in 2018.
OGLE-2018-BLG-0799Lb is a sub-Saturn-mass exoplanet discovered by the Optical Gravitational Lensing Experiment (OGLE) collaboration, through a gravitational microlensing event that occurred in May 2018. The discovery was announced in October 2020, and published in August 2022.
OGLE-2019-BLG-0960Lb is an exoplanet that was discovered in January 2021 by gravitational microlensing. It is approximately twice the mass of Earth, making it a super-Earth. At the time of discovery, it was the lowest mass-ratio planet to be detected via microlensing; that is, the least massive planet relative to the mass of its host star. Its host star, OGLE-2019-BLG-0960L, has an mass between 0.3 and 0.6 M☉.
OGLE-2011-BLG-0462, also known as MOA-2011-BLG-191, is a stellar-mass black hole isolated in interstellar space. OGLE-2011-BLG-0462 lies at a distance of 1,720 parsecs in the direction of the galactic bulge in the constellation Sagittarius. The black hole has a mass of about 6.03 M☉. OGLE-2011-BLG-0462 is the first truly isolated black hole which has been confirmed.
OGLE-2018-BLG-1119Lb is a Jupiter-like gas giant exoplanet located 5,760 parsecs away, orbiting its host star at a distance of 4.06 AU and taking two years to complete one orbit. It is 0.91 times the mass of Jupiter. It was discovered in 2022 by gravitational microlensing.
OGLE-2012-BLG-0950Lb is a sub-Saturn (super-Neptune)-type planet 2,600 parsecs (8,500 ly) away with 39 or 35 Earth masses. This type of planet was once thought to be extremely rare because of runaway gas accretion, which would create a gap between 4 and 8 Earth radii or 20 and 80 Earth masses, peaking around 32-64 Earth masses. The planet is 2.6 AU from its star. It is likely near-impossible to know much else about the planet's properties because it was detected by gravitational microlensing. The mass of the host star is approximately 0.56 solar masses. This exoplanet was the first to have its mass found out using only microlens parallax and lens flux.
