Astronomy:HD 164922
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Hercules |
| Right ascension | 18h 02m 30.86234s[1] |
| Declination | +26° 18′ 46.8050″[1] |
| Apparent magnitude (V) | +6.99[2] |
| Characteristics | |
| Spectral type | G9V[3] |
| B−V color index | 0.799±0.005[2] |
| Astrometry | |
| Radial velocity (Rv) | 20.16±0.12[1] km/s |
| Proper motion (μ) | RA: 389.772[1] mas/yr Dec.: -602.431[1] mas/yr |
| Parallax (π) | 45.4954 ± 0.0167[1] mas |
| Distance | 71.69 ± 0.03 ly (21.980 ± 0.008 pc) |
| Details | |
| Mass | 0.874 ± 0.012[3] M☉ |
| Radius | 0.999 ± 0.017[3] R☉ |
| Luminosity | 0.703 ± 0.017[3] L☉ |
| Surface gravity (log g) | 4.387 ± 0.014[3] cgs |
| Temperature | 5390±30[2] K |
| Metallicity [Fe/H] | 0.16 ± 0.05[3] dex |
| Rotation | 42.3+1.3 −0.7 d[2] |
| Rotational velocity (v sin i) | <2.0[2] km/s |
| Age | 13.4,[4] 9.58+1.99 −1.55[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 164922 is a seventh magnitude G-type main sequence star in the constellation of Hercules. To view it, binoculars or a telescope are necessary, as it is too faint to be visible to the naked eye. It is 71.7 light-years (22.0 parsecs) distant from the Earth.[1] It will soon evolve away from the main-sequence and expand to become a red giant.[citation needed]
Nomenclature
The name HD 164922 derives directly from the fact that the star is the 164,922nd star listed in the Henry Draper catalog. The designation b for its planet derives from the order of discovery. The designation of b is given to the first planet found orbiting a given star, followed by the other lowercase letters of the alphabet.[5] In the case of HD 164922, only one was discovered, which was designated b, followed by three more planets, which were designated c, d, and e.[3][6]
Stellar characteristics
HD 164922 is a G-type main sequence star that is approximately 87% the mass of and 99% the radius of the Sun. It has a temperature of 5390 K and is about 10 billion years old,[2] with estimates ranging as high as 13.4 billion years.[4] In comparison, the Sun is about 4.6 billion years old[7] and has a temperature of 5778 K.[8]
The star is metal-rich, with a metallicity ([Fe/H]) of 0.16, or 144% the solar amount. This is particularly odd for a star as old as HD 164922. Its luminosity (L☉) is 70% of the solar luminosity.[3]
Planetary system
On 15 July 2006, a long period Saturn-mass exoplanet was announced orbiting around HD 164922. This planet orbits at 2.11 AU from the star with a low eccentricity value of 0.05.[9]
Almost exactly ten years later in 2016, another exoplanet, though less massive than the first planet, was discovered orbiting farther in from the star. This planet has a minimum mass of nearly 13 times that of Earth, meaning it is possibly a Neptune-like planet.[3]
A third exoplanet, a hot super-Earth, was discovered in 2020,[2] and a fourth, Neptune-mass, in 2021.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| d | ≥4.74±0.67 M⊕ | 0.1023±0.0012 | 12.4584+0.0019 −0.0023 |
0.18+0.17 −0.12 |
— | — |
| e | ≥10.52+0.99 −0.97 M⊕ |
0.2292+0.0026 −0.0027 |
41.763±0.012 | 0.086+0.083 −0.060 |
— | — |
| c | ≥14.3±1.1 M⊕ | 0.3411±0.0039 | 75.817+0.037 −0.038 |
0.096+0.088 −0.066 |
— | — |
| b | ≥0.344±0.013 MJ | 2.149±0.025 | 1,198.5+3.2 −3.1 |
0.065+0.027 −0.029 |
— | — |
See also
- List of exoplanets discovered between 2000–2009 - HD 164922 b
- List of exoplanets discovered in 2016 - HD 164922 c
- List of exoplanets discovered in 2020 - HD 164922 d
- List of exoplanets discovered in 2021 - HD 164922 e
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 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 Benatti, S.; Damasso, M.; Desidera, S.; Marzari, F.; Biazzo, K.; Claudi, R.; Di Mauro, M. P.; Lanza, A. F. et al. (2020). "The GAPS Programme at TNG -- XXIII. HD 164922 d: a close-in super-Earth discovered with HARPS-N in a system with a long-period Saturn mass companion". Astronomy & Astrophysics 639: A50. doi:10.1051/0004-6361/202037939. Bibcode: 2020A&A...639A..50B.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Fulton, Benjamin J.; Howard, Andrew W.; Weiss, Lauren M.; Sinukoff, Evan; Petigura, Erik A.; Isaacson, Howard; Hirsch, Lea; Marcy, Geoffrey W. et al. (2016). "Three Temperate Neptunes Orbiting Nearby Stars". The Astrophysical Journal 830 (1): 46. doi:10.3847/0004-637X/830/1/46. Bibcode: 2016ApJ...830...46F.
- ↑ 4.0 4.1 Takeda, Genya et al. (February 2007). "Structure and Evolution of Nearby Stars with Planets. II. Physical Properties of ~1000 Cool Stars from the SPOCS Catalog". The Astrophysical Journal Supplement Series 168 (2): 297–318. doi:10.1086/509763. Bibcode: 2007ApJS..168..297T. http://exoplanets.org/SPOCS_evol.html. Retrieved 2011-08-26.
- ↑ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
- ↑ 6.0 6.1 6.2 Rosenthal, Lee J.; Fulton, Benjamin J.; Hirsch, Lea A.; Isaacson, Howard T.; Howard, Andrew W.; Dedrick, Cayla M.; Sherstyuk, Ilya A.; Blunt, Sarah C. et al. (2021), "The California Legacy Survey. I. A Catalog of 178 Planets from Precision Radial Velocity Monitoring of 719 Nearby Stars over Three Decades", The Astrophysical Journal Supplement Series 255 (1): 8, doi:10.3847/1538-4365/abe23c, Bibcode: 2021ApJS..255....8R
- ↑ Fraser Cain (16 September 2008). "How Old is the Sun?". Universe Today. http://www.universetoday.com/18237/how-old-is-the-sun/.
- ↑ Fraser Cain (15 September 2008). "Temperature of the Sun". Universe Today. http://www.universetoday.com/18092/temperature-of-the-sun/.
- ↑ Butler, R. P. et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal 646 (1): 505–522. doi:10.1086/504701. Bibcode: 2006ApJ...646..505B.
- ↑ "HD 164922". NASA Exoplanet Archive. https://exoplanetarchive.ipac.caltech.edu/overview/HD%20164922.
External links
- The Extrasolar Planet Encyclopedia: HD 164922
- SIMBAD: HD 164922
- "ARICNS: HD 164922". ARICNS. Centre of Astronomy, Heidelberg University. https://wwwadd.zah.uni-heidelberg.de/datenbanken/aricns/cnspages/4c4c01461.htm.
Coordinates: 
18h 02m 30.86s, +26° 18′ 46.81″
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