HD 196775
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Delphinus |
| Right ascension | 20h 39m 04.9681s |
| Declination | +15° 50′ 17.5112″ |
| Apparent magnitude (V) | 5.98 |
| Characteristics | |
| Spectral type | B3 V |
| U−B color index | −0.71 |
| B−V color index | −0.16 |
| Astrometry | |
| Radial velocity (Rv) | −4.6±1 km/s |
| Proper motion (μ) | RA: −0.868 mas/yr Dec.: −15.290 mas/yr |
| Parallax (π) | 3.1211±0.0617 mas |
| Distance | 1,050 ± 20 ly (320 ± 6 pc) |
| Absolute magnitude (MV) | −2.05 |
| Details | |
| Mass | 7±0.4 M☉ |
| Radius | 4.13±0.14 R☉ |
| Luminosity | 1,507 L☉ |
| Surface gravity (log g) | 3.97 cgs |
| Temperature | 18,100 K |
| Rotational velocity (v sin i) | 145±6 km/s |
| Age | 36.1±9.5 Myr |
| Other designations | |
| AG+15°2265, BD+15°4220, GC 28785, HD 196775, HIP 101909, HR 7899, SAO 106347, WDS J20391+1550A | |
| Database references | |
| SIMBAD | data |
HD 196775 (HR 7899) is a solitary star in the equatorial constellation Delphinus. It has an apparent magnitude of 5.98, allowing it to be faintly seen with the naked eye. The object is relatively far at a distance of 1,050 light years but is approaching the Solar System with a heliocentric radial velocity of −4.6 km/s. HD 196775 has a high peculiar velocity of 21.8+1.9
−4.1 km/s compared to neighboring stars, indicating that it may be a runaway star.
HD 196775 has a general stellar classification of B3 V, indicating that it is an ordinary B-type main-sequence star. However, once source gives it a class of B4 Vn, making it slightly cooler and having broad absorption lines due to rapid rotation. It has an angular diameter of 0.12 mas, yielding a radius 4.13 times that of the Sun. At present it has 7 times the mass of the Sun and shines at 1507 L☉ from its photosphere at an effective temperature of 18,100 K, giving it a whitish blue hue. HD 196775 is 36 million years old and is spinning rapidly with a projected rotational velocity of 145 km/s.
HD 196775 has four faint optical companions whose parameters are listed below.
| Companion | mv | PA (°) | Year | Sep. (″) |
|---|---|---|---|---|
| B | 12.40 | 154 | 2006 | 5.2 |
| C | 11.31 | 122 | 2012 | 39.9 |
| D | 14.40 | 146 | 2012 | 28.8 |
| E | 14.40 | 33 | 2012 | 23.3 |