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HD 168009 is a star in the northern constellation of Lyra. It has an apparent visual magnitude of 6.3, 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. In about 328,000 years from now, the star will make its closest approach at a distance of around 17 ly (5.1 pc).

This is a solar analog, 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. The spectrum matches a stellar classification of G1 V, 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.

HD 168009 has about the same mass as the Sun, but is 14% larger in radius. 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 six days. The star is radiating 1.43 times the Sun's luminosity from its photosphere at an effective temperature of 5,792 K. 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.

Planetary system

In 2020, a candidate exoplanet was detected orbiting this star. With a minimum mass of 0.03 M_J (9.5 M_E) and an orbital period of 15 days, this would most likely be a hot mini-Neptune. The planet existence was confirmed in 2021.

References

1. ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
2. ^ Soubiran, C.; Triaud, A. (May 2004), "The Top Ten solar analogs in the ELODIE library", Astronomy and Astrophysics, 418 (3): 1089−1100, arXiv:astro-ph/0402094, Bibcode:2004A&A...418.1089S, doi:10.1051/0004-6361:20035708.
3. ^ Mahdi, D.; et al. (March 2016), "Solar twins in the ELODIE archive", Astronomy & Astrophysics, 587: 9, arXiv:1601.01599, Bibcode:2016A&A...587A.131M, doi:10.1051/0004-6361/201527472, S2CID 119205608, A131.
4. ^ 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, Bibcode:2012ApJ...747L..32L, doi:10.1088/2041-8205/747/2/L32, L32.
5. ^ 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, Bibcode:2005PASJ...57...13T, doi:10.1093/pasj/57.1.13.
6. ^ Fuhrmann, Klaus (July 2011), "Nearby stars of the Galactic disc and halo - V", Monthly Notices of the Royal Astronomical Society, 414 (4): 2893−2922, Bibcode:2011MNRAS.414.2893F, doi:10.1111/j.1365-2966.2011.18476.x.
7. ^ McDonald, I.; et al. (2012), "Fundamental parameters and infrared excesses of Hipparcos stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–357, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
8. ^ Hempelmann, A.; et al. (February 2016), "Measuring rotation periods of solar-like stars using TIGRE. A study of periodic CaII H+K S-index variability", Astronomy & Astrophysics, 586: 19, Bibcode:2016A&A...586A..14H, doi:10.1051/0004-6361/201526972, A14.
9. "HD 168009". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-01-18.
10. Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics, 575: 13, arXiv:1412.3648, Bibcode:2015A&A...575A..35B, doi:10.1051/0004-6361/201425221, S2CID 59039482, A35.
11. Sierchio, J. M.; et al. (April 2014), "The Decay of Debris Disks around Solar-type Stars", The Astrophysical Journal, 785 (1): 13, arXiv:1402.6308, Bibcode:2014ApJ...785...33S, doi:10.1088/0004-637X/785/1/33, S2CID 54077869, 33.
12. 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, arXiv:1308.2223, Bibcode:2013ApJ...775...55B, doi:10.1088/0004-637X/775/1/55, S2CID 119113700, 55.
13. ^ 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, arXiv:2012.09190, Bibcode:2021AJ....161..134H, doi:10.3847/1538-3881/abd639, S2CID 229297873.
14. ^ 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, arXiv:2105.11583, Bibcode:2021ApJS..255....8R, doi:10.3847/1538-4365/abe23c, S2CID 235186973

• G-type main-sequence stars
• Solar analogs
• Maunder Minimum
• Planetary systems with one confirmed planet
• Lyra
• Durchmusterung objects
• Gliese and GJ objects
• Henry Draper Catalogue objects
• Hipparcos objects
• Bright Star Catalogue objects
• 2MASS objects