HD 199942
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Equuleus |
| Right ascension | 21h 00m 03.99267s |
| Declination | +07° 30′ 58.3018″ |
| Apparent magnitude (V) | 5.98 (6.23 + 8.13) |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | F1Vp or F1VgF1mA8 |
| B−V color index | 0.283±0.006 |
| Astrometry | |
| Radial velocity (Rv) | −26.2 km/s |
| Proper motion (μ) | RA: +40.810 mas/yr Dec.: +30.445 mas/yr |
| Parallax (π) | 17.7360±0.4820 mas |
| Distance | 184 ± 5 ly (56 ± 2 pc) |
| Absolute magnitude (MV) | 1.59 |
| Orbit | |
| 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 | |
| Mass | 1.65 M☉ |
| Radius | 1.97+0.07 −0.09 R☉ |
| Luminosity | 10.2±0.3 L☉ |
| Surface gravity (log g) | 3.94 cgs |
| Temperature | 7342+181 −115 K |
| Rotational velocity (v sin i) | 159 km/s |
| Age | 1.016 Gyr |
| Other designations | |
| 5 G. Equulei, KUI 102, BD+06°4718, HD 199942, HIP 103652, HR 8038, SAO 126447, WDS J21001+0731AB | |
| Database references | |
| SIMBAD | data |
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. The system is located at a distance of approximately 184 light years based on parallax, and it has an absolute magnitude of 1.59. It is drifting closer with a radial velocity of −26 km/s.
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 will come at its closest to the Sun 2.1 million years from now, at a distance of 124.0 light-years.
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″. The pair orbit each other with a period of 58.4 years and an eccentricity of 0.295. The primary component is of visual magnitude 6.23 and is a chemically-peculiar F-type main-sequence star with a class of F1Vp. The companion is of magnitude 8.13.