| 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−Bcolor index | 0.115[2] |
| B−Vcolor index | 0.635[2] |
| Astrometry | |
| Radial velocity (Rv) | −64.9±0.1[4] km/s |
| Proper motion (μ) | RA: −77.290±0.018mas/yr[1] Dec.: −114.748±0.019mas/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 | |
| BD+45° 2684,GJ 9622,HD 168009,HIP 89474,HR 6847,SAO 47343,2MASS J18153245+4512333[9] | |
| Database references | |
| SIMBAD | data |
HD 168009 is astar in the northernconstellation ofLyra. It has anapparent 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 annualparallax shift of42.93 mas provides a distance estimate of 76 light years. It is moving closer to the Sun with a heliocentricradial 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]
This is asolar 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] Thespectrum matches astellar classification of G1 V,[3] indicating this is an ordinaryG-type main-sequence star that is generating energy throughhydrogen fusion at itscore. The level ofchromospheric activity is low, making it a candidate for aMaunder minimum event.[4]
HD 168009 has about the samemass as the Sun, but is 14% larger in radius.[6] It has a similarmetallicity to the Sun – what astronomers term the abundance of elements other than hydrogen and helium – and is spinning with arotation period of six days.[8] The star is radiating 1.43[7] times theSun's luminosity from itsphotosphere at aneffective temperature of 5,792 K.[4] It has been examined for aninfrared excess that may indicate the presence of acircumstellar disk of dust, but no statistically significant excess was detected.[11][12]
In 2020, a candidateexoplanet was detected orbiting this star. With aminimum mass of 0.03MJ (9.5ME) and an orbital period of 15 days, this would most likely be ahotmini-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 | — | — |