Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Sagittiarus |
Right ascension | 18h 06m 7.44s [1] |
Declination | −31° 24′ 16.12″ [1] |
Characteristics | |
Evolutionary stage | white dwarf [2] |
Variable type | unknown |
Astrometry | |
Distance | 7500 ± 2000 [3] ly (2300 ± 600 [3] pc) |
Details | |
Mass | 0.53±0.11 [2] M☉ |
Other designations | |
Database references | |
SIMBAD | The star |
planet b |
MOA-2010-BLG-477L is a star whose existence was detected when it caused a microlensing event in August, 2010. The microlensing event also revealed the existence of a planet orbiting the star. At first the star was thought to be about 0.67 times the mass of the Sun, [1] in the main-sequence phase of its stellar evolution. [1] [3] But by the time the star should have been separated enough in the sky from the source star of the microlensing event it was not detected, implying that it is actually a dim white dwarf star. [2]
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | 1.5−0.3+1.8 MJ | 2−1+3 | — | — | — | — |
The history of the detection of the planet, MOA-2010-BLG-477 L b, dates back to the year 2010. In that year, a microlensing alert event occurred, before the planet was confirmed conclusively, and was detected independently by the MOA and OGLE collaborations. [1] Following the original microlensing event, astronomers predicted another microlensing peak, which was observed by numerous groups using a wide array of telescopes. [1] One of these telescopes was located in Antarctica, and made the first microlensing detections from that continent; however, the data collected there were too crude to be included in the analysis which eventually confirmed the planet. [1]
The planet was detected by means of microlensing, [1] where gravitational lensing as the planet and its host star pass in front of a background star causes a temporary flare in the amount of light observed, allowing the planet's existence to be known. [1]
Observations from the Keck Observatory in Hawaii allowed a team from Australia and New Zealand to study the system in more detail. They determined that the star was a white dwarf, and that the planet was similar in mass to Jupiter. The gas giant planet was found to be about 2.8 AU, or about 260 million miles, away from the white dwarf star, which is about half the mass of the Sun. [4] [5] The discovery of MOA-2010-BLG-477 L b drew significant attention, as it shows a potential scenario for Jupiter's continued orbit around the Sun in the distant future, after the star's own evolution into a white dwarf. [6]
MOA-2010-BLG-477 L b is the only planet which has been detected orbiting MOA-2010-BLG-477 L. Little is known about this planet, with the only characteristics known about this system are the mass of the planet and its projected separation from its host star. [3]
A rogue planet is an interstellar object of planetary-mass, therefore smaller than fusors and without a host planetary system. Such objects have been ejected from the planetary system in which they formed or have never been gravitationally bound to any star or brown dwarf. The Milky Way alone may have billions to trillions of rogue planets, a range the upcoming Nancy Grace Roman Space Telescope will likely be able to narrow down.
Gravitational microlensing is an astronomical phenomenon due to 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.
An exomoon or extrasolar moon is a natural satellite that orbits an exoplanet or other non-stellar extrasolar body.
OGLE-2005-BLG-390Lb is a super-Earth exoplanet orbiting OGLE-2005-BLG-390L, a star 21,500 ± 3,300 light-years from Earth near the center of the Milky Way, making it one of the most distant planets known. On January 25, 2006, Probing Lensing Anomalies NETwork/Robotic Telescope Network (PLANET/Robonet), Optical Gravitational Lensing Experiment (OGLE), and Microlensing Observations in Astrophysics (MOA) made a joint announcement of the discovery. The planet does not appear to meet conditions presumed necessary to support life.
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-2003-BLG-235L (MOA-2003-BLG-53L) is a star in the constellation of Sagittarius. The first gravitational microlensing event for which a planet orbiting the lens was detected around this star. The event occurred in during July 2003. Two groups observed and independently detected the event: the Optical Gravitational Lensing Experiment (OGLE) and the Microlensing Observations in Astrophysics (MOA), hence, the double designation. It is an orange dwarf star of spectral type K, which is accompanied by a giant planet.
Any planet is an extremely faint light source compared to its parent star. For example, a star like the Sun is about a billion times as bright as the reflected light from any of the planets orbiting it. In addition to the intrinsic difficulty of detecting such a faint light source, the light from the parent star causes a glare that washes it out. For those reasons, very few of the exoplanets reported as of April 2014 have been observed directly, with even fewer being resolved from their host star.
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.
RoboNet-1.0 was a prototype global network of UK-built 2-metre robotic telescopes, the largest of their kind in the world, comprising the Liverpool Telescope on La Palma, the Faulkes Telescope North on Maui (Hawaii), and the Faulkes Telescope South in Australia, managed by a consortium of ten UK universities under the lead of Liverpool John Moores University. For the technological aims of integrating a global network to act effectively as a single instrument, and maximizing the scientific return by applying the newest developments in e-Science, RoboNet adopted the intelligent-agent architecture devised and maintained by the eSTAR project.
MOA-2007-BLG-192Lb, occasionally shortened to MOA-192 b, is an extrasolar planet approximately 3,000 light-years away in the constellation of Sagittarius. The planet was discovered orbiting the brown dwarf or low-mass star MOA-2007-BLG-192L. At a mass of approximately 3.3 times Earth, it is one of the lowest-mass extrasolar planets at the time of discovery. It was found when it caused a gravitational microlensing event on May 24, 2007, which was detected as part of the MOA-II microlensing survey at the Mount John University Observatory in New Zealand.
MOA-2007-BLG-192L is a low-mass red dwarf star or brown dwarf, approximately 3,000 light-years away in the constellation of Sagittarius. It is estimated to have a mass approximately 6% of the Sun's. In 2008, an Earth-sized extrasolar planet was announced to be orbiting this object.
MOA-2007-BLG-400L is a star located approximately 20000 light-years away in the constellation of Sagittarius. This star is presumed to be a red dwarf with a spectral type of M3V, based on its mass of 0.35 MS.
MOA-2007-BLG-400Lb is an extrasolar planet located approximately 20000 light-years away in the constellation of Sagittarius, orbiting the star MOA-2007-BLG-400L. This planet was detected on September 18, 2008 by the gravitational microlensing by Dong. It has mass between 50% to 130% of Jupiter and orbits between 0.6 and 1.1 AU.
An extragalactic planet, also known as an extragalactic exoplanet or an extroplanet, is a star-bound planet or rogue planet located outside of the Milky Way Galaxy. Due to the immense distances to such worlds, they would be very hard to detect directly. However, indirect evidence suggests that such planets exist. Nonetheless, the most distant known planets are SWEEPS-11 and SWEEPS-04, located in Sagittarius, approximately 27,710 light-years from the Sun, while the Milky Way is between 100,000 and 180,000 light years in diameter. This means that even galactic planets located farther than that distance have not been detected.
The Microlensing Follow-Up Network is an informal group of observers who monitor high magnification gravitational microlensing events in the Milky Way's Galactic Bulge. Its goal is to detect extrasolar planets via microlensing of the parent star by the planet. μFUN is a follow-up network - they monitor microlensing events identified by survey groups such as OGLE and Microlensing Observations in Astrophysics (MOA).
MOA-2009-BLG-387Lb is an exoplanet in the orbit of the red dwarf MOA-2009-BLG-387L. Its discovery was announced on February 21, 2011, making it the eleventh planet discovered using gravitational microlensing. The planet is thought to be over twice the mass of Jupiter and to have an orbit 80 percent larger than that of Earth's, lasting approximately 1,970 days. However, its exact characteristics are difficult to constrain because the characteristics of the host star are not well known.
MOA-2009-BLG-387L is a red dwarf in the Sagittarius constellation that is host to the planet MOA-2009-BLG-387Lb. The star is estimated to be nearly 20,000 light years away and approximately one fifth the mass of the Sun, although large confidence intervals exist, reflecting the uncertainties in both the mass and distance. The star drew the attention of astronomers when it became the lens of gravitational microlensing event MOA-2009-BLG-387L, in which it eclipsed a background star and created distorted caustics, an envelope of reflected or refracted light rays. Analysis of the caustic events and of follow-up observational data led to the planet's discovery, which was reported in February 2011.
OGLE-2014-BLG-0124Lb is one of the farthest planets that we know of today. It is approximately 13,000 light years away, located near the center of the galaxy. The planet was discovered using a technique called microlensing. In this case it took 150 days. Two telescopes are used to detect the planet and the time difference between identification by each telescope is used to calculate the distance to the planet. This also contributes to determining the mass of the planet which is about half of Jupiter's. The planet orbits a star with a mass of 0.7 solar masses and is 3.1 AUs from it.
OGLE-2016-BLG-1190Lb is an extremely massive exoplanet, with a mass about 13.4 times that of Jupiter (MJ), or is, possibly, a low mass brown dwarf, orbiting the G-dwarf star OGLE-2016-BLG-1190L, located about 22,000 light years from Earth, in the constellation of Sagittarius, in the galactic bulge of the Milky Way.