HD 168009 is a star in the northern constellation of Lyra. It has an apparent visual magnitude of 6.3,[2] 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.[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 32.463s[1] |
| Declination | +45° 12′ 33.54″[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: −77.290±0.018 mas/yr[1] Dec.: −114.748±0.019 mas/yr[1] |
| Parallax (π) | 42.9348 ± 0.0158 mas[1] |
| Distance | 75.97 ± 0.03 ly (23.291 ± 0.009 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]
Planetary system
editIn 2020, a candidate exoplanet was detected orbiting this star. With a minimum mass of 0.03 MJ (9.5 ME) and an orbital period of 15 days, this would most likely be a hot mini-Neptune.[13] The planet existence was confirmed in 2021.[14]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥0.0300+0.0038 −0.0037 MJ |
0.1192+0.0017 −0.0018 |
15.1479+0.0035 −0.0037 |
0.121+0.110 −0.082 |
— | — |
References
edit- ^ a b c d 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.
- ^ a b c d e f 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.
- ^ a b 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.
- ^ a b c d e f 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.
- ^ a b 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.
- ^ a b c 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.
- ^ a b 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.
- ^ a b 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, S2CID 59039482, 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, S2CID 54077869, 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, S2CID 119113700, 55.
- ^ a b 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.
- ^ a b 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