Kepler-80

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Kepler-80
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension 19h 44m 27s
Declination +39° 58′ 44″
Apparent magnitude (V) 14.804
Characteristics
Spectral type M0V[1]
Astrometry
Proper motion (μ) RA: -6.2[1] mas/yr
Dec.: -8.7[1] mas/yr
Distance ~1100 ly
(~357 pc)
Details
Mass 0.730 M
Radius 0.678 R
Luminosity 0.170 L
Temperature 4540 K
Metallicity [Fe/H] -0.56 [2] dex
Rotation 25.567±0.252 days[3]
Other designations
KOI-500, KIC 4852528, 2MASS J19442701+3958436
Database references
SIMBAD data
KIC data

Kepler-80 is a star in the constellation Cygnus with six planets.[4][5][6]

Planetary system[edit]

The discovery of five planets orbiting the star was announced in October 2012. The planets orbit very near the parent star; the semi-major axis of the outermost planet is 1/12 the distance from Earth to the Sun. The radial velocity method could not be used to confirm the existence of planets due to the star's faintness. The Kepler-80b and Kepler 80c were initially confirmed through the transit-timing variation method. Two of the three other candidates were validated in February 2014.[2][7][8] The innermost planet was validated in 2016.[9]

The Kepler-80 planetary system[2][10][11]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
f 0.0175 0.9867873 ~0 81.36° 1.21 R
d 6.75 M 0.0372 3.0722 ~0 85.94° 1.53 R
e 4.13 M 0.0491 4.6449 ~0 86.52° 1.60 R
b 6.93 M 0.0658 7.0525 ~0 87.66° 2.67 R
c 6.74 M 0.0792 9.5236 ~0 87.66° 2.74 R
g 0.14 14.64558 89.35° 1.13 R

Orbital resonance[edit]

Kepler-80 d, e, b, c and g have orbits locked in a resonance. While their periods are in a ~ 1.000: 1.512: 2.296: 3.100: 4.767 ratio, in a frame of reference that rotates with the conjunctions this reduces to a ratio of 4:6:9:12:18. Conjunctions of d and e, e and b, b and c, and c and g occur at relative intervals of 2:3:6:6 in a pattern that repeats about every 191 days. Librations of possible three-body resonances have amplitudes of only about 3 degrees, and modeling indicates the resonant system is stable to perturbations. Triple conjunctions do not occur.[5][10]

References[edit]

  1. ^ a b c "Kepler-80". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 10 January 2017. 
  2. ^ a b c "OASIS". Abstractsonline.com. Retrieved 2012-11-22. 
  3. ^ McQuillan, A.; Mazeh, T.; Aigrain, S. (2013). "Stellar Rotation Periods of The Kepler objects of Interest: A Dearth of Close-In Planets Around Fast Rotators". The Astrophysical Journal Letters. 775 (1). L11. arXiv:1308.1845Freely accessible. Bibcode:2013ApJ...775L..11M. doi:10.1088/2041-8205/775/1/L11. 
  4. ^ Xie, J.-W. (2013). "Transit timing variation of near-resonance planetary pairs: confirmation of 12 multiple-planet systems". Astrophysical Journal Supplement Series. 208 (2): 22. doi:10.1088/0067-0049/208/2/22. 
  5. ^ a b Shale, C. J.; Vanderburg, A. (2017). "Identifying Exoplanets With Deep Learning: A Five Planet Resonant Chain Around Kepler-80 And An Eighth Planet Around Kepler-90" (PDF). The Astrophysical Journal. Retrieved 2017-12-15. 
  6. ^ St. Fleur, Nicholas (14 December 2017). "An 8th Planet Is Found Orbiting a Distant Star, With A.I.'s Help". The New York Times. Retrieved 15 December 2017. 
  7. ^ "Tiny Alien Solar System Discovery Explained (Infographic) | KOI-500 Exoplanets, Kepler". Space.com. Retrieved 2012-11-22. 
  8. ^ http://www.nasa.gov/sites/default/files/files/arXivValidationMultisII.pdf
  9. ^ http://www.nasa.gov/press-release/nasas-kepler-mission-announces-largest-collection-of-planets-ever-discovered
  10. ^ a b MacDonald, Mariah G.; Ragozzine, Darin; Fabrycky, Daniel C.; Ford, Eric B.; Holman, Matthew J.; Isaacson, Howard T.; Lissauer, Jack J.; Lopez, Eric D.; Mazeh, Tsevi (2016-01-01). "A Dynamical Analysis of the Kepler-80 System of Five Transiting Planets". The Astronomical Journal. 152 (4): 105. arXiv:1607.07540Freely accessible. Bibcode:2016AJ....152..105M. doi:10.3847/0004-6256/152/4/105. 
  11. ^ "Kepler-80 g". NASA Exoplanet Archive. Retrieved 14 December 2017.