Astronomy:HAT-P-20

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Short description: Star in the constellation Gemini
HAT-P-20
Observation data
Equinox J2000.0]] (ICRS)
Constellation Gemini
Right ascension  07h 27m 39.9487s[1]
Declination +24° 20′ 11.5183″[1]
Apparent magnitude (V) 11.35[1]
Characteristics
Spectral type K3V
Astrometry
Radial velocity (Rv)-18.559 km/s
Proper motion (μ) RA: -4.985 mas/yr
Dec.: -96.235 mas/yr
Parallax (π)14.0483 ± 0.0391[1] mas
Distance232.2 ± 0.6 ly
(71.2 ± 0.2 pc)
Details[2][3]
Mass0.798±0.018 M☉
Radius0.744±0.011 R☉
Surface gravity (log g)4.52±0.09 cgs
Temperature4595±45 K
Metallicity0.22±0.09
Rotation14.66±0.03 d
Rotational velocity (v sin i)2.0±0.5 km/s
Age0.8 Gyr
Other designations
Gaia DR2 869913435026514688, 2MASS J07273995+2420118[1]
Database references
SIMBADdata

HAT-P-20 is a K-type main-sequence star about 232 light-years away. The star has a strong starspot activity,[2] and its equatorial plane is misaligned by 36+10−12° with the planetary orbit.[3] Although star with a giant planet on close orbit is expected to be spun-up by tidal forces, only weak indications of tidal spin-up were detected.[4]

Planetary system

In 2010 a transiting hot super-Jovian planet was detected.[5] Its equilibrium temperature is 996±19 K.

Size comparison of HAT-P-20 b and Jupiter
The HAT-P-20 planetary system[5][2][3]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b 7.59±0.12 MJ 0.03671±0.00027 2.8753172±0.0000003 0.0172±0.0016 86.3±0.1° 0.952±0.017 RJ

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 HAT-P-20 -- High proper-motion Star
  2. ↑ 2.0 2.1 2.2 Leilei Sun, Shenghong Gu, Xiaobin Wang at al., "REFINED SYSTEM PARAMETERS AND TTV STUDY OF TRANSITING EXOPLANETARY SYSTEM HAT-P-20", 2017
  3. ↑ 3.0 3.1 3.2 Esposito, M.; Covino, E.; Desidera, S.; Mancini, L.; Nascimbeni, V.; Zanmar Sanchez, R.; Biazzo, K.; Lanza, A. F. et al. (2017), "The GAPS Programme with HARPS-N at TNG. XIII. The orbital obliquity of three close-in massive planets hosted by dwarf K-type stars: WASP-43, HAT-P-20 and Qatar-2.", Astronomy & Astrophysics 601: A53, doi:10.1051/0004-6361/201629720, Bibcode: 2017A&A...601A..53E 
  4. ↑ Salz, M.; Schneider, P. C.; Czesla, S.; Schmitt, J. H. M. M. (2015), "High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood", Astronomy & Astrophysics 576: A42, doi:10.1051/0004-6361/201425243, Bibcode: 2015A&A...576A..42S 
  5. ↑ 5.0 5.1 Bakos, G. Á.; Hartman, J.; Torres, G.; Latham, D. W.; Kovács, Géza; Noyes, R. W.; Fischer, D. A.; Johnson, J. A. et al. (2010), "HAT-P-20b–HAT-P-23b: FOUR MASSIVE TRANSITING EXTRASOLAR PLANETS", The Astrophysical Journal 742 (2): 116, doi:10.1088/0004-637X/742/2/116, Bibcode: 2011ApJ...742..116B 

Coordinates: Sky map 07h 27m 39.9487s, +24° 20′ 11.5183″



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