HD 168009
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).
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 18h 15m 32.463s |
| Declination | +45° 12′ 33.54″ |
| Apparent magnitude (V) | 6.307 |
| Characteristics | |
| Spectral type | G1 V |
| U−B color index | 0.115 |
| B−V color index | 0.635 |
| Astrometry | |
| Radial velocity (Rv) | −64.9±0.1 km/s |
| Proper motion (μ) | RA: −77.290±0.018 mas/yr Dec.: −114.748±0.019 mas/yr |
| Parallax (π) | 42.9348 ± 0.0158 mas |
| Distance | 75.97 ± 0.03 ly (23.291 ± 0.009 pc) |
| Absolute magnitude (MV) | 4.52 |
| Absolute bolometric magnitude (Mbol) | 4.39±0.06 |
| Details | |
| Mass | 0.99 M☉ |
| Radius | 1.14±0.04 R☉ |
| Luminosity | 1.43 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 |
| Rotational velocity (v sin i) | 3 km/s |
| Age | 8.1 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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.