Astronomy:Kepler-18

From HandWiki
(Redirected from Astronomy:Kepler-18b)

Coordinates: Sky map 19h 63m 19.06s, +46° 44′ 47.94″

Kepler-18
Observation data
Equinox J2000.0]] (ICRS)
Constellation Cygnus
Right ascension  19h 52m 19.0688s[1]
Declination +44° 44′ 46.808″[1]
Apparent magnitude (V) 14.0
Characteristics
Spectral type G7
Astrometry
Proper motion (μ) RA: −1.432±0.031[1] mas/yr
Dec.: −20.313±0.028[1] mas/yr
Parallax (π)2.2804 ± 0.0168[1] mas
Distance1,430 ± 10 ly
(439 ± 3 pc)
Details[2]
Mass0.972 ± 0.042 M
Radius1.108 ± 0.051 R
Luminosity0.93 L
Surface gravity (log g)4.32 ± 0.12 cgs
Temperature5383 ± 44 K
Metallicity [Fe/H]0.19 ± 0.06 dex
Rotational velocity (v sin i)<4 km/s
Age10.0 ± 2.3 Gyr
Other designations
KOI-137, KIC 8644288,2MASS J19521906+4444467, Gaia DR2 2079295583282164992[3]
Database references
SIMBADdata
Extrasolar Planets
Encyclopaedia
data

Kepler-18 is a star with almost the same mass as the Sun in the Cygnus constellation.

Planetary system

The star is orbited by 3 confirmed planets, announced in 2011.[2] In 2021, it was found the orbital plane of Kepler-18d is slowly changing, likely under the gravitational influence of the additional giant planet.[4]

The Kepler-18 planetary system[2][5]
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b 6.9 ± 3.4 M 0.0447 ± 0.0006 3.504725 ± 0.000028 84.92 ± 0.26° 2.00 ± 0.10 R
c 17.3 ± 1.9 M 0.0752 ± 0.0011 7.6415716 87.68 ± 0.22° 5.49 ± 0.26 R
d 16.4 ± 1.4 M 0.1172 ± 0.0017 14.858941 88.07 ± 0.1° 6.98 ± 0.33 R

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 Data Release 2 catalog entry
  2. 2.0 2.1 2.2 Cochran, William D. et al. (2011). "Kepler 18-b, c, and d: A System Of Three Planets Confirmed by Transit Timing Variations, Lightcurve Validation, Spitzer Photometry and Radial Velocity Measurements". The Astrophysical Journal Supplement Series 197 (1): 7. doi:10.1088/0067-0049/197/1/7. Bibcode2011ApJS..197....7C. 
  3. "Kepler-18". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=Kepler-18. 
  4. Shahaf, Sahar; Mazeh, Tsevi; Zucker, Shay; Fabrycky, Daniel (2021), "Systematic search for long-term transit duration changes in Kepler transiting planets", Monthly Notices of the Royal Astronomical Society 505: 1293–1310, doi:10.1093/mnras/stab1359, Bibcode2021MNRAS.505.1293S 
  5. Montet, Benjamin T.; Johnson, John Asher (2013), "Model-Independent Stellar and Planetary Masses from Multi-Transiting Exoplanetary Systems", The Astrophysical Journal 762 (2): 112, doi:10.1088/0004-637X/762/2/112, Bibcode2013ApJ...762..112M 

External links