Kepler-42
A red dwarf with three sub-Earth planets in compact orbits.
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Kepler-42, also designated KOI-961, is a red dwarf star in the constellation Cygnus roughly 131 light years from the Sun. It hosts three confirmed extrasolar planets, each smaller than Earth in radius and orbiting very close to the star.
Quick Facts
- Distance from sun
- 131 light years
- Constellation
- Cygnus
- Number of confirmed planets
- 3
- Star mass
- 0.13 times that of the Sun
- Star radius
- 0.17 times that of the Sun
- Star luminosity
- 0.24% of the Sun's
- Star metallicity
- one third of the Sun's
Facts from the source article.
Planetary system
The three transiting planets were discovered in February 2011 and confirmed on 10 January 2012 using the Kepler Space Telescope. Their radii range from approximately that of Mars to that of Venus. This system is only the second known to contain planets of Earth's radius or smaller, after the Kepler-20 system. The orbits are compact, making the system resemble the moon systems of giant planets such as Jupiter or Saturn more than the Solar System.
Detection was possible because the star's small size causes the planets to block a larger proportion of starlight during transits. Orbital eccentricity remains unknown for all planets, as their properties have not been established by methods such as radial velocity. Assuming an extremely high albedo of 0.9 and no greenhouse effect, the outer planet Kepler-42 d would have an equilibrium temperature of about 280 K, similar to Earth's 255 K.
Did You Know?
- Kepler-42 has an appreciable proper motion of up to 431±8 mas/yr.
- The star's radius is just 1.7 times that of the gas giant Jupiter.
More in Planetary Systems with Three Confirmed Planets
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Kepler-42 (CC BY-SA 4.0).
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