MOA-2007-BLG-192Lb

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Exoplanet
MOA-2007-BLG-192Lb

An artistic impression of MOA-2007-BLG-192Lb orbiting its dwarf star.

An artistic impression of MOA-2007-BLG-192Lb orbiting its dwarf star.
Constellation Sagittarius
Position
equinox : J2000.0
Right ascension 18h 08m 04s
declination -27 ° 09 ′ 00 ″
Orbit data
Central star
Further data
Dimensions 3.3 M E
distance 3000 ly pc
history
discovery Bennett et al.
Date of discovery May 30, 2008

MOA-2007-BLG-192Lb is an extrasolar planet orbiting the dwarf star MOA-2007-BLG-192L in the constellation Sagittarius . It is located about 3,000 light years away and has about 3.3 Earth masses. At the time of its discovery, it was one of the smallest known exoplanets. MOA-2007-BLG-192Lb was discovered on May 30, 2008.

Characteristics

MOA-2007-BLG-192Lb orbits its star at about the same distance as Venus orbits our sun . The star has about six to eight percent of the solar mass. With this mass it lies in the border area between real stars , which fuse hydrogen to helium by nuclear fusion, and brown dwarfs .

According to the researchers, the dwarf star shimmers faintly and lilac in the sky of MOA-2007-BLG-192Lb . Outside the planet's atmosphere, the temperatures are low, which are roughly comparable to those on the remote dwarf planet Pluto . MOA-2007-BLG-192Lb probably has a thick atmosphere that allows higher temperatures.

observation

The observation of such an exoplanet is only possible indirectly, since the object is much too small and faint to see it directly. The method used here is called micro-gravitational lensing ( microlensing ). For this, the earth, the observed planet with its home star and a star behind it had to be in a line at the time of discovery.

According to an effect of the general theory of relativity, the observed planet focused the light of the star behind it like a magnifying glass. As a result, the relative movement of MOA-2007-BLG-192Lb and the background star led to a short-term fluctuation in brightness, which was caused by gravitational effects. A precise analysis of the fluctuations in brightness made it possible to determine the mass of the planet and its star.

meaning

Until the discovery of MOA-2007-BLG-192Lb , no planet had ever been found orbiting a star with less than 20 percent of the solar mass. According to the researchers, this planet showed that planets around stars with low mass can be expected, especially in the vicinity of the solar system. The special importance arises from the possibility that one could observe such nearby exoplanets directly with the new James Webb Space Telescope . In contrast, MOA-2007-BLG-192Lb can only be observed indirectly in the foreseeable future (see section on observation ). Meanwhile, the possibility of planets in the vicinity was increased by the discovery of nearby exoplanets such as B. Proxima Centauri b or Ross 128 b confirmed.

See also

Web links