Astronomy:Kepler-38

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Short description: Binary star system in the constellation Lyra
Kepler-38
Observation data
Equinox J2000.0]] (ICRS)
Constellation Lyra
Right ascension  19h 07m 19.2814s[1]
Declination +42° 16′ 45.120″[1]
Characteristics
Spectral type G V[2] / M[3]
Astrometry
Proper motion (μ) RA: −4.648±0.026[1] mas/yr
Dec.: −13.159±0.025[1] mas/yr
Parallax (π)0.8225 ± 0.0145[1] mas
Distance3,970 ± 70 ly
(1,220 ± 20 pc)
Orbit
PrimaryKepler-38A
CompanionKepler-38B
Period (P)18.79537
Semi-major axis (a)0.1469
Eccentricity (e)0.1032
Details
Kepler-38A
Mass0.949 M
Radius1.757 R
Temperature5640 K
Metallicity-0.11
Kepler-38B
Mass0.249 M
Radius0.2724 R
Metallicity-0.11
Other designations
KOI-1740, KIC 6762829, 2MASS J19071928+4216451[4]
Database references
SIMBADdata
KICdata

Kepler-38 is a binary star system in the constellation Lyra. These stars, called Kepler-38A and Kepler-38B have masses of 95% and 25% solar masses respectively. The brighter star is spectral class G while the secondary has spectral class M. They are separated by 0.147 AU, and complete an eccentric orbit around a common center of mass every 18.8 days.[2]

Planetary system

In 2012, a circumbinary Neptune-sized planet was found transiting the brighter star. Follow-up radial velocity measurements did not give sufficient information to constrain the mass of the planet. The planet was confirmed via transit duration variation method.

It is likely that additional planets in the habitable zone exist, including rocky terrestrial planets, according to simulations of the formation of the Kepler-38 system; furthermore, the orbits of any such planets are probably stable.[5]

The Kepler-38 planetary system
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b 0.4644 105.595 0.39 RJ

See also

References

  1. 1.0 1.1 1.2 1.3 1.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. 2.0 2.1 Orosz, Jerome A. et al. (2012), "THE NEPTUNE-SIZED CIRCUMBINARY PLANET KEPLER-38b", The Astrophysical Journal 758 (2): 87, doi:10.1088/0004-637X/758/2/87, Bibcode2012ApJ...758...87O 
  3. "Notes for star Kepler-38(AB)". Extrasolar Planets Encyclopaedia. 2012. http://exoplanet.eu/star.php?st=Kepler-38%28AB%29. [|permanent dead link|dead link}}]
  4. "Kepler-38". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Kepler-38. 
  5. Macau, E E N.; Domingos, R. C.; Izidoro, A.; Amarante, A.; Winter, O. C.; Barbosa, G. O. (2020), "Earth-size planet formation in the habitable zone of circumbinary stars", Monthly Notices of the Royal Astronomical Society 494: 1045–1057, doi:10.1093/mnras/staa757