HD 168009

HD 168009
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]
Distance75.97 ± 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]
Mass0.99 M☉
Radius1.14±0.04[6] R☉
Luminosity1.43[7] L☉
Surface gravity (log g)4.31 cgs
Temperature5,792±80 K
Metallicity [Fe/H]−0.02 dex
Rotation5.985±0.019 d[8]
Rotational velocity (v sin i)3[5] km/s
Age8.1 Gyr
Other designations
BD+45° 2684, GJ 9622, HD 168009, HIP 89474, HR 6847, SAO 47343, 2MASS J18153245+4512333[9]
Database references
SIMBADdata

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]

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]

  1. ^ a b c d Cite error: The named reference EDR3 was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference Soubiran2004 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Mahdi2016 was invoked but never defined (see the help page).
  4. ^ a b c d e f Cite error: The named reference Lubin2012 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Takeda2005 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Klauss2011 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference McDonald2012 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Hempelmann2016 was invoked but never defined (see the help page).
  9. ^ "HD 168009". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-01-18.
  10. ^ Cite error: The named reference BailerJones2015 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Sierchio2014 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Ballering2013 was invoked but never defined (see the help page).