Kepler-62

Kepler-62

Kepler-62f (foreground) and Kepler-62e (right) are habitable zone exoplanets orbiting the star Kepler-62 (center). (Artists' conception.) Credit: NASA Ames/JPL-Caltech
Observation data Epoch J2000      Equinox J2000
Constellation	Lyra
Right ascension	18h 52m 51.060s
Declination	+45° 20′ 59.507″
Apparent magnitude (V)	13.75
Characteristics
Spectral type	K2V
B−V color index	0.832
Astrometry
Proper motion (μ)	RA: −11.1 mas/yr Dec.: −29.3 mas/yr
Distance	~1200 ly (~368 pc)
Details
Mass	0.69 ± 0.02 M☉
Radius	0.64 ± 0.02 R☉
Luminosity (bolometric)	0.21 ± 0.02  L☉
Surface gravity (log g)	4.68 ± 0.04 cgs
Temperature	4925 ± 70 K
Metallicity [Fe/H]	−0.209  dex
Rotation	39.3 ± 0.6 days
Rotational velocity (v sin i)	0.4 ± 0.5 km/s
Age	7 ± 4 Gyr
Other designations
KIC 9002278, KOI-701
Database references
SIMBAD	data
Extrasolar Planets Encyclopaedia	data

Kepler-62 is a star somewhat cooler and smaller than the Sun in the constellation Lyra, 1,200 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission used to detect planets that may be transiting their stars. On April 18, 2013 it was announced that the star has five planets, two of which, Kepler-62e and Kepler-62f, are likely solid planets within the star's habitable zone.

Nomenclature and history

Prior to Kepler observation, Kepler-62 had the 2MASS catalogue number 2MASS J18525105+4520595. In the Kepler Input Catalog it has the designation of KIC 9002278, and when it was found to have transiting planet candidates it was given the Kepler object of interest number of KOI-701.

The Kepler Space Telescope search volume, in the context of the Milky Way.

The star's planets were discovered by NASA's Kepler Mission, a mission tasked with discovering planets in transit around their stars. The transit method that Kepler uses involves detecting dips in brightness in stars. These dips in brightness can be interpreted as planets whose orbits move in front of their stars from the perspective of Earth. The name Kepler-62 derives directly from the fact that the star is the catalogued 62nd star discovered by Kepler to have confirmed planets.

The designations b, c, d, e, and f derive from the order of discovery. The designation of b is given to the first planet orbiting a given star, followed by the other lowercase letters of the alphabet. In the case of Kepler-62, all of the known planets in the system were discovered at one time, so b is applied to the closest planet to the star and f to the farthest.

Stellar characteristics

Kepler-62 is a K-type star that is approximately 69% the mass of and 64% the radius of the Sun. It has a surface temperature of 4925 ± 70 K and is 7 ± 4 billion years old. In comparison, the Sun is about 4.6 billion years old and has a surface temperature of 5778 K.

The star's apparent magnitude, or how bright it appears from Earth's perspective, is 13.75. Therefore, it is too dim to be seen with the naked eye.

Planetary system

All known planets transit the star; this means that all five planets' orbits appear to cross in front of their star as viewed from the Earth's perspective. Their inclinations relative to Earth's line of sight, or how far above or below the plane of sight they are, vary by less than one degree. This allows direct measurements of the planets' periods and relative diameters (compared to the host star) by monitoring each planet's transit of the star.

The radii of the planets fall between 0.54 and 1.95 Earth radii. Of particular interest are the planets e and f, as they are the best candidates for solid planets falling into the habitable zone of their star. Their radii, 1.61 and 1.41 Earth radii respectively, put them in a radius range where they may be solid terrestrial planets. Their positions within the Kepler-62 system mean that they fall within Kepler-62's habitable zone: the distance range where, for a given chemical composition (significant amounts of carbon dioxide for Kepler-62f, and a protective cloud cover for Kepler-62e), these two planets could have liquid water on their surfaces, perhaps completely covering them.

Comparisons

Star Systems - Kepler-62 System and the Solar System

Planet Sizes - Kepler-69c, Kepler-62e, Kepler-62f, and Earth.

The masses of the planets could not be directly determined using either the radial velocity or the transit timing method; this failure leads to weak upper limits for the planets' masses. For e and f, that upper limit amounts to 36 and 35 Earth masses, respectively; the real masses are expected to be significantly lower.

The Kepler-62 system

Planet (in order from star)	Maximum Mass (ME)	Semimajor axis (AU)	Orbital period (d)	e cos ω	e sin ω	Inclination (°)	Radius (RE)
b	<9	0.0553 ± 0.0005	5.714932 ± 0.000009	0.01 ± 0.14	−0.07 ± 0.05	89.2 ± 0.4	1.31 ± 0.04
c	<4	0.0929 ± 0.0009	12.4417 ± 0.00001	−0.05 ± 0.14	−0.18 ± 0.11	89.7 ± 0.2	0.54 ± 0.03
d	<14	0.120 ± 0.001	18.16406 ± 0.00002	−0.03 ± 0.24	0.09 ± 0.06	89.7 ± 0.3	1.95 ± 0.07
e	<36	0.427 ± 0.004	122.3874 ± 0.0008	0.05 ± 0.21	−0.12 ± 0.02	89.98 ± 0.02	1.61 ± 0.05
f	<35	0.718 ± 0.007	267.291 ± 0.005	−0.05 ± 0.14	0.08 ± 0.11	89.90 ± 0.03	1.41 ± 0.07

See also

• Kepler Mission
• List of planetary systems

External links

• Kepler Mission – NASA.
• Kepler – Discoveries – Summary Table – NASA.
• Kepler – Discovery of New Planetary Systems (2013).
• Kepler – Tally of Planets/interactive (2013) – NYT.
• Video (02:27) - NASA Finds Three New Planets in "Habitable Zone" (04/18/2013).