HD 168009
HD 168009 is a star in the northern constellation of Lyra. It has an apparent visual magnitude of 6.3,[2] placing it just below the normal limit of stars visible to the naked eye under good viewing conditions. 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.[4] In about 328,000 years from now, the star will make its closest approach at a distance of around 17 ly (5.1 pc).[10]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 18h 15m 32.4634s[1] |
| Declination | +45° 12′ 33.541″[1] |
| Apparent magnitude (V) | 6.307[2] |
| Characteristics | |
| Spectral type | G1 V[3] |
| U−B color index | 0.115[2] |
| B−V color index | 0.635[2] |
| Astrometry | |
| Radial velocity (Rv) | −64.9±0.1[4] km/s |
| Proper motion (μ) | RA: −77.288[1] mas/yr Dec.: −114.757[1] mas/yr |
| Parallax (π) | 42.93 ± 0.22[1] mas |
| Distance | 76.0 ± 0.4 ly (23.3 ± 0.1 pc) |
| Absolute magnitude (MV) | 4.52[2][5] |
| Absolute bolometric magnitude (Mbol) | 4.39±0.06[6] |
| Details[4] | |
| Mass | 0.99 M☉ |
| Radius | 1.14±0.04[6] R☉ |
| Luminosity | 1.43[7] L☉ |
| Surface gravity (log g) | 4.31 cgs |
| Temperature | 5,792±80 K |
| Metallicity [Fe/H] | −0.02 dex |
| Rotation | 5.985±0.019 d[8] |
| Rotational velocity (v sin i) | 3[5] km/s |
| Age | 8.1 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a solar analog,[2] 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.[4] The spectrum matches a stellar classification of G1 V,[3] 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.[4]
HD 168009 has about the same mass as the Sun, but is 14% larger in radius.[6] 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.[8] The star is radiating 1.43[7] times the Sun's luminosity from its photosphere at an effective temperature of 5,792 K.[4] 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.[11][12]
In 2020, a candidate exoplanet was detected orbiting this star. With a minimum mass of 0.03 MJ (9.5 M⊕) and an orbital period of 15 days, this would most likely be a hot mini-Neptune.[13]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b (unconfirmed) | ≥0.03+0.004 −0.004 MJ |
0.11958+0.00002 −0.00002 |
15.148+0.003 −0.004 |
0.1+0.1 −0.1 |
— | — |
References
- Gaia Collaboration; et al. (2016), "Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties", Astronomy & Astrophysics, 595: A2, arXiv:1609.04172, Bibcode:2016A&A...595A...2G, doi:10.1051/0004-6361/201629512.
- Soubiran, C.; Triaud, A. (May 2004), "The Top Ten solar analogs in the ELODIE library", Astronomy and Astrophysics, 418: 1089−1100, arXiv:astro-ph/0402094, Bibcode:2004A&A...418.1089S, doi:10.1051/0004-6361:20035708.
- 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, A131.
- 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.
- 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.
- 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.
- McDonald, I.; et al. (2012), "Fundamental parameters and infrared excesses of Hipparcos stars", Monthly Notices of the Royal Astronomical Society, 427: 343, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
- 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.
- "HD 168009". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-01-18.
- 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, A35.
- 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, 33.
- 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, 55.
- 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, arXiv:2012.09190, Bibcode:2020arXiv201209190H.