Giant Planet Microlensing Event

A giant planet microlensing event

A Hubble image of a red galaxy acting as a gravitational lens for a more distant blue galaxy, bending its light into an arc. Exoplanets can be detected through a similar effect, gravitational microlensing, when a foreground star and its orbiting planet happen to pass a background star in the sky, producing bright flashes. Astronomers have discovered a new Jupiter-sized exoplanet microlensing around an M dwarf star and are using the result to help decide between competing planet-forming scenarios. Source: ESA/Hubble and NAS

Over 5,000 exoplanets have been discovered to date, more than 90% of which have been found using transit or radial velocity techniques. Of the other 10%, 105 were found using the microlens method, which takes advantage of the fact that the path of a ray of light is bent by the presence of a solid body. The body’s gravitational force acts like a lens (a “gravitational lens”) to distort the image of an object visible behind it. When a massive object happens to pass in front of a star, it acts as a gravitational lens, and its motion across the sky briefly brightens the background star. If the foreground object is a star that hosts a planet, both bodies can produce brightening events as they pass in front of the star, and the flashes as seen from Earth can be modeled to account for their mass and distance determine.

Microlensing offers two major advantages over more common exoplanet detection techniques. First, the brightness of the microlensing effect does not depend on the brightness of the moving body, but only on its mass, making it possible to detect faint, low-mass M dwarf stars. The second advantage is that the microlensing planet can orbit its star at great distances, even in many astronomical units. (Since normal

exoplanet
An exoplanet (or extrasolar planet) is a planet that is outside of our solar system and orbits a star other than the Sun. The first suspected scientific discovery of an exoplanet was in 1988, and the first confirmation of the discovery was in 1992.

” data-gt-translate-attributes=”[{” attribute=””>exoplanet techniques, like transiting, require multiple detections over many orbital periods, exoplanets with large orbits take years to complete their cycle and so far the vast majority of all measured exoplanets have orbits smaller than one astronomical unit.) As a result of their large orbits, the detected giant planets around microlensing host stars are usually far enough away to reside beyond the “snow line,” the distance at which surface water would freeze.

Harvard-Smithsonian Center for Astrophysics (
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