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]
In 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 |
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