Astronomy:HD 168009
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Lyra[1] |
| Right ascension | 18h 15m 32.463s[2] |
| Declination | +45° 12′ 33.54″[2] |
| Apparent magnitude (V) | 6.307[3] |
| Characteristics | |
| Spectral type | G1 V[4] |
| U−B color index | 0.115[3] |
| B−V color index | 0.635[3] |
| Astrometry | |
| Radial velocity (Rv) | −64.9±0.1[5] km/s |
| Proper motion (μ) | RA: −77.290±0.018[2] mas/yr Dec.: −114.748±0.019[2] mas/yr |
| Parallax (π) | 42.9348 ± 0.0158[2] mas |
| Distance | 75.97 ± 0.03 ly (23.291 ± 0.009 pc) |
| Absolute magnitude (MV) | 4.52[3][6] |
| Absolute bolometric magnitude (Mbol) | 4.39±0.06[7] |
| Details[5] | |
| Mass | 0.99 M☉ |
| Radius | 1.14±0.04[7] R☉ |
| Luminosity | 1.43[8] L☉ |
| Surface gravity (log g) | 4.31 cgs |
| Temperature | 5,792±80 K |
| Metallicity [Fe/H] | −0.02 dex |
| Rotation | 30.1+1.1 −0.9 d[9] |
| Rotational velocity (v sin i) | 3[6] km/s |
| Age | 8.1 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 168009 is a star in the northern constellation of Lyra. It has an apparent visual magnitude of 6.3,[3] placing it just above to below the normal limit of stars visible to the naked eye under good viewing conditions of 6-6.5. An annual parallax shift of 42.93 mas provides a distance estimate of 76 light years. It is moving closer to the Sun with a heliocentric radial velocity of −65 km/s.[5] In about 328,000 years from now, the star will make its closest approach at a distance of around 17 ly (5.1 pc).[11]
This is a solar analog,[3] which means its measured properties are similar to those of the Sun. However, it is much older than the Sun with an estimated age of around 8.1 billion years.[5] The spectrum matches a stellar classification of G1 V,[4] indicating this is an ordinary G-type main-sequence star that is generating energy through hydrogen fusion at its core. The level of chromospheric activity is low, making it a candidate for a Maunder minimum event.[5]
HD 168009 has about the same mass as the Sun, but is 14% larger in radius.[7] It has a similar metallicity to the Sun – what astronomers term the abundance of elements other than hydrogen and helium – and is spinning with a rotation period of 30 days.[9] The star is radiating 1.43[8] times the Sun's luminosity from its photosphere at an effective temperature of 5,792 K.[5] It has been examined for an infrared excess that may indicate the presence of a circumstellar disk of dust, but no statistically significant excess was detected.[12][13]
Planetary system
In 2020, a candidate exoplanet was detected orbiting this star. With a minimum mass of 0.03 |♃|J}}}}}} (9.5 M⊕) and an orbital period of 15 days, this would most likely be a hot mini-Neptune.[14] The planet existence was confirmed in 2021.[15]
Evidence for a second planet, HD 168009 c, in radial velocity data, was presented in 2026. However, it is still not possible to conclude if the radial velocity signal is truly caused by an orbiting planet, or simply an artifact of stellar activity. If confirmed, the planet would orbit at a period of 27.8 days and have a minimum mass of 7 M🜨.[9]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥8.61+0.85 −0.86 M⊕ |
0.1218+0.0011 −0.0012 |
15.1437+0.0027 −0.0026 |
0.08+0.08 −0.05 |
— | — |
| c (unconfirmed) | ≥6.83+1.46 −1.50 M⊕ |
0.1823±0.0017 | 27.7579+0.0130 −0.0249 |
0.11+0.12 −0.08 |
— | — |
References
- ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R. Constellation record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Soubiran, C.; Triaud, A. (May 2004), "The Top Ten solar analogs in the ELODIE library", Astronomy and Astrophysics 418 (3): 1089−1100, doi:10.1051/0004-6361:20035708, Bibcode: 2004A&A...418.1089S.
- ↑ 4.0 4.1 Mahdi, D. et al. (March 2016), "Solar twins in the ELODIE archive", Astronomy & Astrophysics 587: 9, doi:10.1051/0004-6361/201527472, A131, Bibcode: 2016A&A...587A.131M.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 Lubin, Dan et al. (March 2012), "Frequency of Maunder Minimum Events in Solar-type Stars Inferred from Activity and Metallicity Observations", The Astrophysical Journal Letters 747 (2): 6, doi:10.1088/2041-8205/747/2/L32, L32, Bibcode: 2012ApJ...747L..32L.
- ↑ 6.0 6.1 Takeda, Yoichi et al. (February 2005), "High-Dispersion Spectra Collection of Nearby F--K Stars at Okayama Astrophysical Observatory: A Basis for Spectroscopic Abundance Standards", Publications of the Astronomical Society of Japan 57 (1): 13–25, doi:10.1093/pasj/57.1.13, Bibcode: 2005PASJ...57...13T.
- ↑ 7.0 7.1 7.2 Fuhrmann, Klaus (July 2011), "Nearby stars of the Galactic disc and halo - V", Monthly Notices of the Royal Astronomical Society 414 (4): 2893−2922, doi:10.1111/j.1365-2966.2011.18476.x, Bibcode: 2011MNRAS.414.2893F.
- ↑ 8.0 8.1 McDonald, I. et al. (2012), "Fundamental parameters and infrared excesses of Hipparcos stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–357, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ 9.0 9.1 9.2 9.3 Gupta, Arvind F.; Logsdon, Sarah E.; Luhn, Jacob K.; Fitzmaurice, Evan; Mahadevan, Suvrath; Robertson, Paul; Ford, Eric B.; Bender, Chad F.; Giovinazzi, Mark R.; Halverson, Samuel; Han, Te; Krolikowski, Daniel M.; Lin, Andrea S. J.; Ninan, Joe P.; III, Palumbo; L., Michael; Paredes, Leonardo A.; Rajagopal, Jayadev; Roy, Arpita; Schwab, Christian; Stefansson, Gudmundur; Terrien, Ryan C.; Wright, Jason T., "The NEID Earth Twin Survey. VI. Discovery of a Low-Mass Planet Orbiting HD 126053 and RV Signals Near the Rotation Periods of HD 168009 and HD 10780", arXiv:2609.32097 [astro-ph.EP].
- ↑ "HD 168009". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+168009.
- ↑ Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics 575: 13, doi:10.1051/0004-6361/201425221, A35, Bibcode: 2015A&A...575A..35B.
- ↑ Sierchio, J. M. et al. (April 2014), "The Decay of Debris Disks around Solar-type Stars", The Astrophysical Journal 785 (1): 13, doi:10.1088/0004-637X/785/1/33, 33, Bibcode: 2014ApJ...785...33S.
- ↑ Ballering, Nicholas P. et al. (September 2013), "A Trend between Cold Debris Disk Temperature and Stellar Type: Implications for the Formation and Evolution of Wide-orbit Planets", The Astrophysical Journal 775 (1): 14, doi:10.1088/0004-637X/775/1/55, 55, Bibcode: 2013ApJ...775...55B.
- ↑ Hirsch, Lea A. et al. (December 2020), "Understanding the Impacts of Stellar Companions on Planet Formation and Evolution: A Survey of Stellar and Planetary Companions within 25 pc", The Astronomical Journal 161 (3): 134, doi:10.3847/1538-3881/abd639, Bibcode: 2021AJ....161..134H.
- ↑ Rosenthal, Lee J. 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
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