HD 207229 b

HIP 107773
Location of HIP 107773 in Indus (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Indus[note 1]
Right ascension 21h 50m 0.12s[1]
Declination −64° 42′ 45.1″[1]
Apparent magnitude (V) 5.6[1]
Characteristics
Evolutionary stage Horizontal branch[2][3]
Spectral type K0III[1]
B−V color index 0.99[4]
Astrometry
Radial velocity (Rv)−0.1701±0.1237[5] km/s
Proper motion (μ) RA: −0.7032±0.0807 mas/yr[5]
Dec.: −37.4432±0.0893 mas/yr[5]
Parallax (π)9.5919 mas[1]
Distance343.9±2.6 ly
(105.5±0.8 pc)[2]
Absolute magnitude (MV)0.54[4]
Details[3]
Mass2.42±0.27 M☉
Radius11.6±1.4 R☉
Luminosity74.13+1.12
−1.15 L☉
Surface gravity (log g)2.6±0.2 cgs
Temperature4945±100 K
Age>1[2] Gyr
Other designations
2MASS J21500013-6442451, FK5 3742, HD 207229, HR 8331, IRAS 21461-6456, PPM 365403, SAO 255080, TIC 406320735, TYC 9119-2234-1[1]
Database references
SIMBADdata

HIP 107773 is a star located 344 light years from Earth in the southern constellation Indus.[2][note 1] It is classified as a horizontal branch K-type giant star,[2][3] having a spectral type K0III[1] and a radius of 11.6 R☉.[5] With an apparent magnitude of 5.6, the star can be faintly seen with the naked eye.[1] It has an exoplanet, HIP 107773 b, a gas giant orbiting it at a distance of 0.72 astronomical units (108,000,000 km),[6] about the same distance from Venus to the Sun.[a]

Characteristics

HIP 107773 is a giant star, having a spectral type K0III,[1] where K0 means it is a K-type star and III (luminosity class) means it is a giant star. The star is in the horizontal branch phase of evolution.[3][2] HIP 107773 has a radius equivalent to 11.6 solar radii, and a mass equivalent to about 2.4 solar masses.[3] It is cooler than the Sun, having an effective temperature of 4,945 K (4,672 °C).[3][b] Given the mass and the evolutionary stage of the star, its age is estimated to be at least about one billion years.[2]

Planetary system

HIP 107773 has an exoplanet, HIP 107773 b, discovered in 2015 using the radial velocity method.[6][3] The planet is classified as a gas giant, having a minimum mass of 2 MJ[3] and an estimated radius of 1.19 RJ.[6] It orbits its star at a distance of 0.72 astronomical units (108,000,000 km), about the same distance as Venus is from the Sun,[a] and completes one orbit every 144 days (0.39 years).[3] Its orbit is almost circular, with an eccentricity of just 0.09.[3]

With a mass of 2.4 M☉, the star HIP 107773 is one of the most massive stars with a close-in planet.[3][9]

The HIP 107773 planetary system[3]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ≥1.98±0.21 MJ 0.72±0.03 144.3±0.5 0.09±0.06 — 1.19 (estimate)[6] RJ

See also

Notes and references

  1. ^ a b c d e f g h i j "HIP 107773". SIMBAD. Retrieved January 21, 2024.
  2. ^ a b c d e f g Ginski, C.; Mugrauer, M.; Adam, C.; Vogt, N.; Holstein, R. G. van (2021-05-01). "How many suns are in the sky? A SPHERE multiplicity survey of exoplanet host stars - I. Four new close stellar companions including a white dwarf". Astronomy & Astrophysics. 649: A156. arXiv:2009.10363. doi:10.1051/0004-6361/202038964. ISSN 0004-6361.
  3. ^ a b c d e f g h i j k l Jones, M. I.; Jenkins, J. S.; Rojo, P.; Olivares, F.; Melo, C. H. F. (2015-08-01). "Giant planets around two intermediate-mass evolved stars and confirmation of the planetary nature of HIP 67851c". Astronomy & Astrophysics. 580: A14. arXiv:1505.06718. doi:10.1051/0004-6361/201525853. ISSN 0004-6361.
  4. ^ a b "HIP-107773 (Star)". In-The-Sky.org. Retrieved January 21, 2024.
  5. ^ a b c "HIP 107773 Overview". NASA Exoplanet Archive. Retrieved January 21, 2024.
  6. ^ a b c d "HIP 107773b". Exoplanet Exploration: Planets Beyound Our Solar System. Retrieved January 21, 2024.
  7. ^ "Venus Fact Sheet". nssdc.gsfc.nasa.gov. Retrieved January 21, 2024.
  8. ^ "Sun Fact Sheet". nssdc.gsfc.nasa.gov. Retrieved January 21, 2024.
  9. ^ "HIP 107773 b". Open Exoplanet Catalogue. Retrieved January 21, 2024.
  1. ^ a b The distance from Venus to the Sun is 0.723 AU.[7]
  2. ^ For comparison, the effective temperature of the Sun is 5,772 K (5,499 °C).[8]
  1. ^ a b Obtained with a right ascension of 21h 50m 0.12s and a declination of −64° 42′ 45.1″[1] on this website.