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.[6]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Crater |
| Right ascension | 11h 17m 47.55306s[1] |
| Declination | –23° 58′ 31.4969″[1] |
| Apparent magnitude (V) | +8.05[2] |
| Characteristics | |
| Spectral type | K0III/IV[3] |
| Astrometry | |
| Radial velocity (Rv) | −10.52±0.12[1] km/s |
| Proper motion (μ) | RA: −130.715 mas/yr[1] Dec.: −16.761 mas/yr[1] |
| Parallax (π) | 8.8365±0.0234 mas[1] |
| Distance | 369.1 ± 1.0 ly (113.2 ± 0.3 pc) |
| Absolute magnitude (MV) | +2.6[4] |
| Details | |
| Mass | 1.41[2] M☉ |
| Radius | 4.6[2] R☉ |
| Luminosity | 8.284[5] L☉ |
| Surface gravity (log g) | 3.36[2] cgs |
| Temperature | 4,925[2] K |
| Age | 4[4] Gyr |
| Other designations | |
| Hunahpú, CD−23 9857, HD 98219, HIP 55174, SAO 179747 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
Planetary system
editA 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.[6]
| 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
edit- 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- 1 2 3 4 5 6 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.
- ↑ 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.
- 1 2 3 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.
- ↑ 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.
- 1 2 "Name ExoWorlds Honduras". NameExoWorlds. IAU. Retrieved 21 December 2019.
 | This subgiant-star-related article is a stub. You can help Wikipedia by adding missing information. |