MOA-2010-BLG-477L is a star whose existence was detected when it caused a

microlensing event 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 ...

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, in the

main-sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hert ...

phase of its

stellar evolution Stellar evolution is the process by which a star changes over the course of time. Depending on the mass of the star, its lifetime can range from a few million years for the most massive to trillions of years for the least massive, which is cons ...

. 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 A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes fro ...

star.

Planetary system

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 Moa are extinct giant flightless birds native to New Zealand. The term has also come to be used for chicken in many Polynesian cultures and is found in the names of many chicken recipes, such as Kale moa and Moa Samoa. Moa or MOA may also refer ...

and

OGLE Ogle may refer to: Places * Ogle County, Illinois, United States * Original name of Ashton, Illinois, a village * Ogle, Kentucky, United States, an unincorporated community * Ogle Township, Somerset County, Pennsylvania, United States * Ogle, Nor ...

collaborations. Following the original microlensing event, astronomers predicted another microlensing peak, which was observed by numerous groups using a wide array of telescopes. 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. The planet was detected by means of

microlensing 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 ...

, where

gravitational lensing A gravitational lens is a distribution of matter (such as a galaxy cluster, cluster of galaxies) between a distant light source and an observer that is capable of bending the light from the source as the light travels toward the observer. This ...

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. 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 Jupiter is the fifth planet from the Sun and the List of Solar System objects by size, largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but ...

. The gas giant planet was found to be about 2.8 AU, or about 260 million miles, away from the

white dwarf star A white dwarf is a stellar core remnant composed mostly of electron-degenerate matter. A white dwarf is very dense: its mass is comparable to the Sun's, while its volume is comparable to the Earth's. A white dwarf's faint luminosity comes f ...

, which is about half the mass of the Sun. 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. 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 This glossary of astronomy is a list of definitions of terms and concepts relevant to astronomy and cosmology, their sub-disciplines, and related fields. Astronomy is concerned with the study of celestial objects and phenomena that originate outsid ...

from its host star.

References

{{DEFAULTSORT:MOA-2010-BLG-477L Sagittarius (constellation) Planetary systems with one confirmed planet White dwarfs