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Kepler-70

Kepler-70
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 19h 45m 25s
Declination +41° 5′ 34″
Apparent magnitude (V) 14.87
Characteristics
Spectral type sdB
Apparent magnitude (U) 13.80
Apparent magnitude (B) 14.71
Apparent magnitude (R) 15.43
Apparent magnitude (I) 15.72
Apparent magnitude (J) 15.36
Apparent magnitude (H) 15.59
Astrometry
Distance 3849 ± 310ly
(1180 ± 95pc)
Details
Mass 0.496 ± 0.002 M
Radius 0.203 ± 0.007 R
Luminosity (bolometric) 22.9 ±  3.1 L
Temperature 27,730 ± 260 K
Other designations
2MASS J19452546+4105339, KIC 5807616, KOI-55, UCAC2 46165657, UCAC3 263-170867, USNO-B1.0 1310-00349976.
Database references
SIMBAD data
KIC data

Kepler-70, formerly known as KOI-55, is a star in the constellation Cygnus with an apparent visual magnitude of 14.87. This is too faint to be seen with the naked eye; viewing it requires a telescope with an aperture of 40 cm (20 in) or more.

A subdwarf B star, Kepler-70 passed through the red giant stage some 18.4 million years ago. In its present day state, it is fusing helium in its core. Once it runs out of helium it will contract to form a white dwarf. It has a relatively small radius of about 0.2 times the Sun's radius; white dwarfs are generally much smaller. The star is host to a planetary system with two planets, Kepler-70b and Kepler-70c. The innermost planet has the highest temperature of any known planet known so far.

On December 26, 2011, evidence for two extremely short-period planets was announced. They were detected by the reflection of starlight caused by the planets themselves, rather than through a variation in apparent stellar magnitude caused by them transiting the star.

The measurements also suggested a smaller body between the two confirmed planets; this remains unconfirmed.

Orbits of Kepler-70b and Kepler-70c have 7:10 orbital resonance and have the closest approach between planets of any known planetary system.


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