Astronomy:HD 164604
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 03m 06.93302s[1] |
| Declination | –28° 33′ 38.3488″[1] |
| Apparent magnitude (V) | 9.62[2] |
| Characteristics | |
| Spectral type | K3.5V(k)[3] |
| Apparent magnitude (B) | 11.016[2] |
| Apparent magnitude (J) | 7.784±0.024[2] |
| Apparent magnitude (H) | 7.306±0.038[2] |
| Apparent magnitude (K) | 7.169±0.020[2] |
| B−V color index | 1.396±0.491[2] |
| Astrometry | |
| Radial velocity (Rv) | 7.30±0.16[1] km/s |
| Proper motion (μ) | RA: −34.658[1] mas/yr Dec.: −42.253[1] mas/yr |
| Parallax (π) | 24.9867 ± 0.0351[1] mas |
| Distance | 130.5 ± 0.2 ly (40.02 ± 0.06 pc) |
| Absolute magnitude (MV) | 6.57[2] |
| Details[4] | |
| Mass | 0.77±0.02 M☉ |
| Radius | 0.78±0.02 R☉ |
| Luminosity | 0.26±0.01 L☉ |
| Surface gravity (log g) | 4.49±0.41 cgs |
| Temperature | 4,663±31 K |
| Metallicity [Fe/H] | 0.12±0.07 dex |
| Rotation | 19±3 d |
| Age | 10.7±3.8 or 1.6±0.7 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Extrasolar Planets Encyclopaedia | data |
HD 164604 is a single star in the southern constellation of Sagittarius. It has the proper name Pincoya, as selected in the NameExoWorlds campaign by Chile, during the 100th anniversary of the IAU. Pincoya is a female water spirit from southern Chilean mythology who is said to bring drowned sailors to the Caleuche so that they can live in the afterlife.[6][7] A 2015 survey ruled out the existence of any stellar companions at projected distances from 13 to 340 astronomical units.[8] It is known to host a single super-Jupiter exoplanet.[9]
This star is invisible to the naked eye with an apparent visual magnitude of 9.62.[2] It is located at a distance of 130.5 light-years from the Sun based on parallax, and is drifting further away with a radial velocity of +7 km/s.[1] The stellar classification of HD 164604 is K3.5V(k), which indicates this is a K-type main-sequence star. The chromosphere is considered very inactive.[3] It is roughly seven[10] billion years old with 77% of the mass and radius of the Sun. The star is radiating 26% of the luminosity of the Sun from its photosphere at an effective temperature of 4,663 K.[4]
Planetary system
A super-Jupiter exoplanet (HD 164604 b, later named Caleuche) was detected by the Magellan Planet Search Program in 2010 based on radial velocity variations of the host star.[9] The orbit of this body does not preclude a hypothetical Earth-mass exoplanet from occupying a dynamically stable orbit within the habitable zone of this star.[11] An astrometric measurement of the planet's inclination and true mass was published in 2022 as part of Gaia DR3.[12]
A second planet was found in 2026 from combined analysis of radial velocity and astrometry. This is another super-Jupiter on a wider orbit. There are two possible orbital solutions, with the outer planet's orbit being either prograde or retrograde to the inner planet's orbit. The retrograde solution is dynamically stable, while the prograde solution may be unstable. Gaia DR4 astrometry should make it possible to determine which solution is correct.[4]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Caleuche | 13.2+1.8 −1.5 or 8.8+1.9 −1.5 MJ |
1.362±0.012 | 653.9+1.5 −1.7 |
0.479+0.027 −0.021 |
10.6+1.4 −1.3 or 16.0+3.5 −2.8° |
— |
| c | 9.5±1.2 or 7.6±1.0 MJ |
5.556+0.093 −0.10 |
5387+120 −127 |
0.196±0.078 | 8.6+1.3 −1.0 or 169.3+1.3 −1.7° |
— |
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 Gray, R. O. et al. (July 2006). "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample". The Astronomical Journal 132 (1): 161–170. doi:10.1086/504637. Bibcode: 2006AJ....132..161G.
- ↑ 4.0 4.1 4.2 4.3 Xiao, Guang-Yao et al. (February 2026). "HD 164604 c: a second giant planet on a 15-yr orbit and the constraint of the planet-planet mutual inclination". The Astronomical Journal.
- ↑ "HD 164604". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+164604.
- ↑ "Approved names" (in en). http://www.nameexoworlds.iau.org/final-results.
- ↑ "Name Exo Worlds". International Astronomical Union | IAU. https://www.iau.org/news/pressreleases/detail/iau1912/.
- ↑ Mugrauer, M.; Ginski, C. (12 May 2015). "High-contrast imaging search for stellar and substellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society 450 (3): 3127–3136. doi:10.1093/mnras/stv771. Bibcode: 2015MNRAS.450.3127M. https://academic.oup.com/mnras/article/450/3/3127/1063872. Retrieved 19 June 2020.
- ↑ 9.0 9.1 Arriagada, Pamela et al. (2010). "Five Long-period Extrasolar Planets in Eccentric orbits from the Magellan Planet Search Program". The Astrophysical Journal 711 (2): 1229–35. doi:10.1088/0004-637X/711/2/1229. Bibcode: 2010ApJ...711.1229A.
- ↑ Pace, G. (March 2013), "Chromospheric activity as age indicator. An L-shaped chromospheric-activity versus age diagram", Astronomy & Astrophysics 551: 4, doi:10.1051/0004-6361/201220364, L8, Bibcode: 2013A&A...551L...8P.
- ↑ Agnew, Matthew T. et al. (November 2017). "Stable habitable zones of single Jovian planet systems". Monthly Notices of the Royal Astronomical Society 471 (4): 4494–4507. doi:10.1093/mnras/stx1449. Bibcode: 2017MNRAS.471.4494A.
- ↑ Gaia Collaboration et al. (2023). "Gaia Data Release 3". Astronomy & Astrophysics 674: A34. doi:10.1051/0004-6361/202243782.
Further reading
- Feng, Fabo et al. (June 2019). "Search for Nearby Earth Analogs. I. 15 Planet Candidates Found in PFS Data". The Astrophysical Journal Supplement Series 242 (2): 31. doi:10.3847/1538-4365/ab1b16. 25. Bibcode: 2019ApJS..242...25F.
Coordinates: 
18h 03m 06.95s, −28° 33′ 38.3″
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