HD 199942

HD 199942
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Equuleus
Right ascension 21h 00m 03.99267s[1]
Declination +07° 30′ 58.3018″[1]
Apparent magnitude (V) 5.98[2] (6.23 + 8.13)[3]
Characteristics
Evolutionary stage Main sequence[4]
Spectral type F1Vp[3] or F1VgF1mA8[5]
B−V color index 0.283±0.006[2]
Astrometry
Radial velocity (Rv)−26.2[2] km/s
Proper motion (μ) RA: +40.810[1] mas/yr
Dec.: +30.445[1] mas/yr
Parallax (π)17.7360 ± 0.4820 mas[1]
Distance184 ± 5 ly
(56 ± 2 pc)
Absolute magnitude (MV)1.59[2]
Orbit[6]
Period (P)58.40 yr
Semi-major axis (a)0.295″
Eccentricity (e)0.295
Inclination (i)130.8°
Longitude of the node (Ω)192.0°
Periastron epoch (T)1959.09
Argument of periastron (ω)
(secondary)		318.1°
Details
A
Mass1.65[7] M☉
Radius1.97+0.07
−0.09[1] R☉
Luminosity10.2±0.3[1] L☉
Surface gravity (log g)3.94[7] cgs
Temperature7342+181
−115[1] K
Rotational velocity (v sin i)159[4] km/s
Age1.016[7] Gyr
Other designations
5 G. Equulei, KUI 102, BD+06°4718, HD 199942, HIP 103652, HR 8038, SAO 126447, WDS J21001+0731AB[8]
Database references
SIMBADdata

HD 199942 is a binary star system in the northern constellation of Equuleus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.98.[2] The system is located at a distance of approximately 184 light years based on parallax, and it has an absolute magnitude of 1.59.[2] It is drifting closer with a radial velocity of −26 km/s.[2]

This system is moving through the galaxy at a velocity of 30.3 km/s relative to the Sun. Its galactic orbit carry it somewhere between 25100-22000 light years from the galactic core, and it'll come at its closest to the Sun 2.1 million years from now, at a distance of 124.0 light-years.[2]

The binary nature of this system was discovered in 1934 by G. P. Kuiper, who found the pair had an angular separation of 0.3″.[3] The pair orbit each other with a period of 58.4 years and an eccentricity of 0.295.[6] The primary component is of visual magnitude 6.23 and is a chemically-peculiar F-type main-sequence star with a class of F1Vp.[3] The companion is of magnitude 8.13.[3]

  1. ^ a b c d e f g h 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 Anderson2012 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Mason2014 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference zorec2012 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Abt1981 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Hartkopf2006 was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference David2015 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).