Astronomy:Kepler-1638

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Short description: G-type star in the constellation Cygnus
Kepler-1638
Cygnus constellation map.svg
Constellation where Kepler-1638 is located
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cygnus[1]
Right ascension  19h 41m 55.76712s[2]
Declination +48° 31′ 27.9998″[2]
Apparent magnitude (V) 14.769±0.206[3]
Characteristics
Evolutionary stage main sequence star
Spectral type G4V[citation needed]
Apparent magnitude (J) 13.550±0.023[4]
Apparent magnitude (H) 13.204±0.024[4]
Apparent magnitude (K) 13.138±0.035[4]
Variable type Planetary transit,[3] rotationally variable[4]
Astrometry
Proper motion (μ) RA: −5.092[2] mas/yr
Dec.: +5.839[2] mas/yr
Parallax (π)0.6462 ± 0.0165[2] mas
Distance5,000 ± 100 ly
(1,550 ± 40 pc)
Details[3]
Mass0.9700+0.0490
−0.0590
 M
Radius0.9500+0.1660
−0.0790
 R
Temperature5710.0+96.696
−111.431
 K
Metallicity [Fe/H]−0.0100+0.1410
−0.1880
 dex
Age4.37+4.19
−2.59
 Gyr
Other designations
KOI-5856, KIC 11037818, 2MASS J19415577+4831280[4]
Database references
SIMBADdata

Kepler-1638 is a G-type main-sequence star located about 5,000 light years away in the constellation of Cygnus.[1] One known exoplanet has been found orbiting the star: Kepler-1638b.[5][6][7][8]As of January 2021, Kepler-1638 is the farthest star with a known exoplanet orbiting in the habitable zone.[9]

Planetary system

The Kepler-1638 planetary system[3]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b ~4.16 M 0.745+0.021
−0.020
259.33683±0.01303 89.9954+0.0021
−0.0844
°
1.87+0.33
−0.22
 R

Kepler-1638 b is an exoplanet in orbit of its star, Kepler-1638, located in the constellation Cygnus. It was confirmed in 2016 as part of a study statistically validating hundreds of Kepler planets. Based on the parameters in the discovery paper, the planet is a super-Earth, with a radius of 1.87+0.33
−0.22
 R
, and a predicted mass of 4.16 Earths. It has an orbit of 259.337±0.013 days in its system's habitable zone and orbits 0.745 AU from its star. It is the most distant known exoplanet that is considered potentially habitable.[3][8][5][6][7]

However, these parameters were estimated before the first measurement of the host star's parallax was published as part of Gaia DR2 in 2018. The Gaia parallax suggests a distance of about 1,548 parsecs (5,050 light-years),[2] much farther than the pre-Gaia estimate of about 764 parsecs (2,490 light-years).[10] This revised distance results in a significantly larger estimate of the radius of the star, and thus of the planet, with a 2018 study finding a planetary radius of 3.226+0.201
−0.315
 R
. This would make the planet an ice giant like Neptune, and thus not potentially habitable in an Earth-like sense.[11][3]

References

  1. 1.0 1.1 Staff (2 August 2008). "Finding the constellation which contains given sky coordinates". DJM.cc. http://djm.cc/constellation.html. Retrieved 16 July 2020. 
  2. 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. 3.0 3.1 3.2 3.3 3.4 3.5 "Kepler-1638". https://exoplanetarchive.ipac.caltech.edu/overview/Kepler-1638. 
  4. 4.0 4.1 4.2 4.3 4.4 "Kepler-1638". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Kepler-1638. 
  5. 5.0 5.1 Burgess, Matt (2016-05-11). "Nasa's Kepler telescope just found 1,284 exoplanets" (in en-GB). Wired UK. ISSN 1357-0978. https://www.wired.co.uk/article/kepler-planets-new-exoplanets. Retrieved 2021-01-22. 
  6. 6.0 6.1 "Exoplanet-catalog". https://exoplanets.nasa.gov/exoplanet-catalog/2284/kepler-1638-b/. 
  7. 7.0 7.1 May 2016, Mike Wall 11 (11 May 2016). "1st Alien Earth Still Elusive Despite Huge Exoplanet Haul" (in en). https://www.space.com/32852-alien-earth-search-nasa-kepler-space-telescope.html. 
  8. 8.0 8.1 Morton, Timothy D.; Bryson, Stephen T.; Coughlin, Jeffrey L.; Rowe, Jason F.; Ravichandran, Ganesh et al. (May 2016). "False Positive Probabilities for all Kepler Objects of Interest: 1284 Newly Validated Planets and 428 Likely False Positives". The Astrophysical Journal 822 (2): 86. doi:10.3847/0004-637X/822/2/86. Bibcode2016ApJ...822...86M. 
  9. "The Habitable Exoplanets Catalog - Planetary Habitability Laboratory @ UPR Arecibo". http://phl.upr.edu/projects/habitable-exoplanets-catalog. 
  10. Torres, Guillermo (December 2017). "Validation of Small Kepler Transiting Planet Candidates in or near the Habitable Zone". The Astronomical Journal 154 (6): 264. doi:10.3847/1538-3881/aa984b. Bibcode2017AJ....154..264T. 
  11. Berger, Travis A.; Huber, Daniel; Gaidos, Eric; van Saders, Jennifer L. (October 2018). "Revised Radii of Kepler Stars and Planets Using Gaia Data Release 2". The Astrophysical Journal 866 (2): 99. doi:10.3847/1538-4357/aada83. Bibcode2018ApJ...866...99B. 

See also