HD 98219

HD 98219, also named Hunahpú, is a subgiant star in the constellation Crater. It has a confirmed exoplanet. At around 4 billion years old, it is a star around 1.3 times as massive as the Sun that has cooled and expanded to 4.5 times the Sun's diameter, brightening to be around 11 times as luminous.[4] The International Astronomical Union (IAU) gave the opportunity to Honduras to name the star Hunahpú as part of NameExoWorlds. Hunahpú was one of the twin gods who became the Sun in K'iche' (Quiché) Mayan mythology.[5]

HD 98219 / Hunahpú
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Crater
Right ascension 11h 17m 47.5531s[1]
Declination –23° 58′ 31.4952″[1]
Apparent magnitude (V) +8.05[2]
Characteristics
Spectral type K0III/IV[3]
Astrometry
Radial velocity (Rv)-10.30[1] km/s
Proper motion (μ) RA: −130.770±0.068[1] mas/yr
Dec.: −16.887±0.050[1] mas/yr
Parallax (π)8.7662 ± 0.0489 mas[1]
Distance372 ± 2 ly
(114.1 ± 0.6 pc)
Absolute magnitude (MV)+2.6[4]
Details
Mass1.41[2] M☉
Radius4.6[2] R☉
Luminosity8.284[1] L☉
Surface gravity (log g)3.36[2] cgs
Temperature4,925[2] K
Age4[4] Gyr
Database references
SIMBADdata

Planetary system

A gas giant planet with a minimum mass almost double that of Jupiter was discovered as part of a radial velocity survey of subgiant stars at Keck Observatory.[4] The International Astronomical Union (IAU) has named it Ixbalanqué, the twin brother of Hunahpú.[5]

The HD 98219 planetary system[2]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b / Ixbalanqué ≥1.964±0.099 MJ 1.26±0.12 433.8±2.0 0.079±0.040 — —

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Luhn, Jacob K.; et al. (2019). "Retired A Stars and Their Companions. VIII. 15 New Planetary Signals around Subgiants and Transit Parameters for California Planet Search Planets with Subgiant Hosts". The Astronomical Journal. 157 (4). 149. arXiv:1811.03043. Bibcode:2019AJ....157..149L. doi:10.3847/1538-3881/aaf5d0. S2CID 102486961.
  3. Houk, N.; Smith-Moore, M. (1988). Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Declinations -26°.0 to -12°.0. Bibcode:1988mcts.book.....H.
  4. Johnson, John Asher; et al. (2011). "Retired a Stars and Their Companions. VII. 18 New Jovian Planets". The Astrophysical Journal Supplement Series. 197 (2). 26. arXiv:1108.4205. Bibcode:2011ApJS..197...26J. doi:10.1088/0067-0049/197/2/26.
  5. "Name ExoWorlds Honduras". NameExoWorlds. IAU. Retrieved 21 December 2019.


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