HD 172044

HD 172044
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Lyra
Right ascension 18h 36m 37.34437s[1]
Declination 33° 28′ 08.5352″[1]
Apparent magnitude (V) 5.41[2] + 10.7[3]
Characteristics
Spectral type B8IIpHgMn[4]
U−B color index −0.509[2]
B−V color index −0.101±0.003[2]
Astrometry
A
Radial velocity (Rv)−32.5±0.8[5] km/s
Proper motion (μ) RA: −7.966[1] mas/yr
Dec.: +0.690[1] mas/yr
Parallax (π)6.0990 ± 0.0893 mas[1]
Distance535 ± 8 ly
(164 ± 2 pc)
Absolute magnitude (MV)−0.53[2]
B
Proper motion (μ) RA: −7.403[6] mas/yr
Dec.: +0.479[6] mas/yr
Parallax (π)6.2391 ± 0.0221 mas[6]
Distance523 ± 2 ly
(160.3 ± 0.6 pc)
Orbit[7]
Period (P)1675 d
Semi-major axis (a)≥71.6×108 km
Eccentricity (e)0.16
Periastron epoch (T)2,420,438.5 JD
Argument of periastron (ω)
(secondary)		120°
Semi-amplitude (K1)
(primary)		3.2 km/s
Details
A
Mass3.65±0.50[8] M☉
Luminosity262.17[2] L☉
Surface gravity (log g)3.90[9] cgs
Temperature14,500[9] K
Metallicity [Fe/H]−0.25[2] dex
Rotational velocity (v sin i)34[9] km/s
Other designations
BD+33°3154, GC 25443, HD 172044, HIP 91235, HR 6997, SAO 67164, CCDM J18366+3328, WDS J18366+3328, GSC 02641-02396[10]
Database references
SIMBADdata

HD 172044 is a triple star[11] system in the northern constellation of Lyra. It has a blue-white hue and is visible to the naked eye with an apparent visual magnitude of 5.41.[2] The distance to the primary component is approximately 535 light years based on parallax.[1] It is drifting closer with a radial velocity of −32.5 km/s, and is predicted to come as near as 77.3 light-years to the Sun some 4.5 million years from now.[2]

The dual nature of the primary star, component A, was announced in 1973 by H. A. Abt and M. A. Snowden. It is a single-lined spectroscopic binary with a preliminary orbital period of 4.59 years and an eccentricity (ovalness) of 0.16.[7] The visible component is a B-type bright giant with a stellar classification of B8IIpHgMn,[4] where the suffix notation indicates it is a chemically peculiar mercury-manganese star.[9]

Component B is a magnitude 9.40 companion of an unknown spectral type.[12] It was first reported by F. G. W. Struve in 1830. As of 2016, it has an angular separation of 7.2 arcseconds along a position angle of 204° from the brighter component.[3]

  1. ^ a b c d e f Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d e f g h Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Mason_et_al_2014 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Osawa1959 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference GaiaDR2_B was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Abt_Snowden_1973 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Hohle_et_al_2010 was invoked but never defined (see the help page).
  9. ^ a b c d Cite error: The named reference Ghazaryan_et_al_2018 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD_A was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Eggleton_Tokovinin_2008 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD_B was invoked but never defined (see the help page).