HD 156668

HD 156668
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Hercules
Right ascension 17h 17m 40.49053s[1]
Declination +29° 13.6′ 38.0243″[1]
Apparent magnitude (V) +8.424[2]
Characteristics
Spectral type K3 V[2]
U−B color index 0.27
B−V color index 1.015[2]
Astrometry
Radial velocity (Rv)-9.427 km/s
Proper motion (μ) RA: -72.481±0.016 mas/yr[3]
Dec.: +216.849±0.019 mas/yr[3]
Parallax (π)41.1103 ± 0.0169 mas[3]
Distance79.34 ± 0.03 ly
(24.325 ± 0.010 pc)
Absolute magnitude (MV)6.480[2]
Details
Mass0.772 ± 0.020[2] M☉
Radius0.720 ± 0.013[2] R☉
Luminosity0.230 ± 0.018[2] L☉
Surface gravity (log g)4.60 ± 0.12[2] cgs
Temperature4850 ± 88[2] K
Metallicity [Fe/H]+0.05 ± 0.06[2] dex
Rotation51.5 days[2]
Rotational velocity (v sin i)0.50 ± 1.0[2] km/s
Age8.6 ± 4.8[2] Gyr
Other designations
BD+29° 2979, HD 156668, HIP 84607, SAO 84984, Wolf 646, 2MASS J17174049+2913378[4]
Database references
SIMBADdata

HD 156668 is a star in the northern constellation of Hercules constellation. With an apparent visual magnitude of 8.4[2] it is too faint to be viewed with the naked eye, but it can be seen with even a small telescope.[5] The distance to this object has been determined directly using the parallax technique, yielding a value of about 80 light-years (25 parsecs).[1]

This star has the stellar classification of a K2 dwarf, with approximately 77% of the mass of the Sun and about 72% of the Sun's diameter. While they are on the main sequence, lower mass stars like this generate energy much more slowly than the Sun. As a result, this star is radiating only 23% of the Sun's bolometric luminosity. HD 156668 is emitting this energy from its outer atmosphere at an effective temperature of around 4850 K,[2] giving it the cool orange glow of a K-type star.[6] It is slightly more enriched in iron compared to the Sun and is rotating at a leisurely rate of once every 51.5 days. Although much older than the Sun, this star is only middle-aged at about 8.6 billion years.[2]

The HD 156668 exhibits a stellar activity cycle with a period about 10 years.[7]

  1. ^ a b c Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c d e f g h i j k l m n o p Cite error: The named reference apj726_2_73 was invoked but never defined (see the help page).
  3. ^ a b 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.
  4. ^ Cite error: The named reference Simbad was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference sherrod_koed2003 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference csiro was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Rosenthal2021 was invoked but never defined (see the help page).