HAT-P-18

HAT-P-18
Observation data
Epoch J2000      Equinox J2000
Constellation Hercules
Right ascension 17h 05m 23.1475s[1]
Declination +33° 00′ 44.940″[1]
Apparent magnitude (V) 12.759[2]
Characteristics
Spectral type K2V
Astrometry
Radial velocity (Rv)-11.83 km/s
Proper motion (μ) RA: −14.002(9) mas/yr[1]
Dec.: −36.751(11) mas/yr[1]
Parallax (π)6.1863 ± 0.0093 mas[1]
Distance527.2 ± 0.8 ly
(161.6 ± 0.2 pc)
Details[3]
Mass0.750+0.015
−0.014 M☉
Radius0.7202+0.0095
−0.01 R☉
Luminosity0.27±0.04[4] L☉
Surface gravity (log g)4.599±0.013 cgs
Temperature4835+39
−35 K
Metallicity0.044+0.060
−0.051
Rotation14.66±0.03 d[4]
Rotational velocity (v sin i)0.5±0.5[4] km/s
Age12.4+4.4
−6.4[4] Gyr
Other designations
Gaia DR2 1334573817793362560, GSC 02594-00646, 2MASS J17052315+3300450[5]
Database references
SIMBADdata

HAT-P-18 is a K-type main-sequence star about 530 light-years away. The star is very old and has a concentration of heavy elements similar to solar abundance.[4] A survey in 2015 detected very strong starspot activity on HAT-P-18.[6]

  1. ^ a b c d Cite error: The named reference Gaia DR3 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Hartman2010 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Wang2021 was invoked but never defined (see the help page).
  4. ^ a b c d e Everett, Mark E.; Howell, Steve B.; Silva, David R.; Szkody, Paula (2013), "Spectroscopy of Faint Kepler Mission Exoplanet Candidate Host Stars", The Astrophysical Journal, 771 (2): 107, arXiv:1305.0578, Bibcode:2013ApJ...771..107E, doi:10.1088/0004-637X/771/2/107, S2CID 119270620
  5. ^ Cite error: The named reference simbad was invoked but never defined (see the help page).
  6. ^ Piskorz, Danielle; Knutson, Heather A.; Ngo, Henry; Muirhead, Philip S.; Batygin, Konstantin; Crepp, Justin R.; Hinkley, Sasha; Morton, Timothy D. (2015), "Friends of Hot Jupiters. III. An Infrared Spectroscopic Search for Low-Mass Stellar Companions", The Astrophysical Journal, 814 (2): 148, arXiv:1510.08062, Bibcode:2015ApJ...814..148P, doi:10.1088/0004-637X/814/2/148, S2CID 11525988