HD 172051

HD 172051
Observation data
Epoch J2000      Equinox J2000
Constellation Sagittarius
Right ascension 18h 38m 53.40151s[1]
Declination −21° 03′ 06.7415″[1]
Apparent magnitude (V) 5.85[2]
Characteristics
Spectral type G5 V[2]
B−V color index 0.68[3]
Astrometry
Radial velocity (Rv)+37.14±0.20[1] km/s
Proper motion (μ) RA: −75.128±0.163[1] mas/yr
Dec.: −153.645±0.150[1] mas/yr
Parallax (π)76.6355 ± 0.1082 mas[1]
Distance42.56 ± 0.06 ly
(13.05 ± 0.02 pc)
Absolute magnitude (MV)5.27[4]
Details
Mass0.865[5] or 1.00[6] M☉
Radius0.90[5] R☉
Surface gravity (log g)4.65[2] cgs
Temperature5,638[2] K
Metallicity [Fe/H]–0.21[2] dex
Rotational velocity (v sin i)0.32[7] km/s
Age4.1–4.8[8] Gyr
Other designations
86 G. Sagittarii, BD−21° 5081, GJ 722, HD 172051, HIP 91438, HR 6998, SAO 187086, WDS J18389-2103AB[9]
Database references
SIMBADdata

HD 172051 (86 G. Sagittarii) is a single,[10] yellow-hued star in the southern constellation of Sagittarius. The star is barely bright enough to be seen with the naked eye, having an apparent visual magnitude of 5.85.[2] Based upon an annual parallax shift of 76.64 mas, it is located some 43 light years from the Sun. It is moving away from the Sun with a radial velocity of +37 km/s.[1]

This ordinary G-type main-sequence star is considered a solar analog, having physical properties sufficiently similar to the Sun. It has a stellar classification of G5 V[2] and is around 4.5 billion years old. The mass is similar to the Sun, although it is cooler and has a lower luminosity. Due to this similarity, HD 172051 has been selected as an early target star for both the Terrestrial Planet Finder and Darwin missions, which seek to find an Earth-like extrasolar planet.[11] During a search for brown dwarf companions using the Hale Telescope in 2004, two candidate companions were identified at angular separations of 5″ and 6″. However, these were determined to be background stars.[12]

  1. ^ a b c d e f g Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f g Cite error: The named reference AAA541_A40 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference mnrassa27_11 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Holmberg2009 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference apjss168_2_297 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference aa552_A78_62 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference aaa520_A79 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference apj687 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference BBC031107 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference pasp122_896_1195 was invoked but never defined (see the help page).