Kepler-62

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Kepler-62
Kepler-62f with 62e as Morning Star.jpg
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[1]
Declination +45° 20′ 59.507″[1]
Apparent magnitude (V) 13.75[2]
Characteristics
Spectral type K2V[2]
B−V color index 0.832[2]
Astrometry
Proper motion (μ) RA: −11.1[3] mas/yr
Dec.: −29.3[3] mas/yr
Distance ~1200 ly
(~368[2] pc)
Details
Mass 0.69 ± 0.02[2] M
Radius 0.64 ± 0.02[2] R
Luminosity (bolometric) 0.21 ± 0.02 [2] L
Surface gravity (log g) 4.68 ± 0.04[2] cgs
Temperature 4925 ± 70[2] K
Metallicity [Fe/H] −0.209 [1] dex
Rotation 39.3 ± 0.6 days[2]
Rotational velocity (v sin i) 0.4 ± 0.5[2] km/s
Age 7 ± 4[2] Gyr
Other designations
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[citation needed] within the star's habitable zone.[2][4]

Nomenclature and history[edit]

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 Galaxy.

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.[5] 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.[2]

Stellar characteristics[edit]

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.[2] In comparison, the Sun is about 4.6 billion years old[6] and has a surface temperature of 5778 K.[7]

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[edit]

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.[2]

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, on the other hand, 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,[2] perhaps completely covering them.[8][9]

Kepler-62 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.[2]

The Kepler-62 system[2]
Planet
(in order from star)

Mass (ME)

Semimajor
axis
(AU)
Orbital period (d) e cos ω[note 1] e sin ω[note 2] Inclination (°) Radius (RE)
b <2.1 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 <0.1 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 <5.5 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 <3.6 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 <2.6 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[edit]

Notes[edit]

  1. ^ e cos ω refers to the product of the orbital eccentricity (e) with the cosine of the periapsis angle (ω).
  2. ^ e sin ω refers to the product of the orbital eccentricity (e) with the sine of the periapsis angle (ω).

References[edit]

  1. ^ a b c "Kepler Input Catalog search result". Space Telescope Science Institute. Retrieved 18 April 2013. 
  2. ^ a b c d e f g h i j k l m n o p q r s Borucki, William J.; et al. (18 April 2013). "Kepler-62: A Five-Planet System with Planets of 1.4 and 1.6 Earth Radii in the Habitable Zone". Science Express. arXiv:1304.7387. Bibcode:2013Sci...340..587B. doi:10.1126/science.1234702. Retrieved 18 April 2013. 
  3. ^ a b Rybka, S. P.; et al. (1997). GPM - compiled catalogue of absolute proper motions of stars in selected areas of sky with galaxies. Bibcode:1997KFNT...13e..70R. 
  4. ^ Johnson, Michele; Harrington, J.D. (18 April 2013). "NASA's Kepler Discovers Its Smallest 'Habitable Zone' Planets to Date". NASA. Retrieved 18 April 2013. 
  5. ^ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A. et al. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR]. Bibcode 2010arXiv1012.0707H.
  6. ^ Fraser Cain (16 September 2008). "How Old is the Sun?". Universe Today. Retrieved 19 February 2011. 
  7. ^ Fraser Cain (15 September 2008). "Temperature of the Sun". Universe Today. Retrieved 19 February 2011. 
  8. ^ "Water worlds surface: Planets covered by global ocean with no land in sight". Harvard Gazette. 2013-04-18. Retrieved 2013-04-19. 
  9. ^ Kaltenegger, L.; Sasselov, D.; Rugheimer, S. (2013-04-18 [preprint]). "Water Planets in the Habitable Zone: Atmospheric Chemistry, Observable Features, and the case of Kepler-62e and -62f". The Astrophysical Journal. arXiv:1304.5058. Bibcode:2013arXiv1304.5058K. 

External links[edit]

Coordinates: Sky map 18h 52m 51.06s, +45° 20′ 59.5″