HD 178233 is a single[9] star in the northern constellation of Lyra. It is bright enough to be dimly visible to the naked eye with an apparent visual magnitude of 5.53,[2] making it a sixth magnitude star. The distance to HD 178233 is 134 light years based on parallax measurements, but it is drifting closer to the Sun with a radial velocity of approximately −24 km/s.[5]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 19h 06m 37.7345s[1] |
| Declination | +28° 37′ 42.941″[1] |
| Apparent magnitude (V) | 5.53[2] |
| Characteristics | |
| Spectral type | F0III[3] or A7V[4] |
| U−B color index | +0.04 |
| B−V color index | 0.296±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | −24.0±4.3[5] km/s |
| Proper motion (μ) | RA: 75.662[1] mas/yr Dec.: 85.291[1] mas/yr |
| Parallax (π) | 24.3974 ± 0.0867 mas[1] |
| Distance | 133.7 ± 0.5 ly (41.0 ± 0.1 pc) |
| Absolute magnitude (MV) | 2.52[2] |
| Details | |
| Mass | 1.54[6] M☉ |
| Radius | 1.83+0.10 −0.06[1] R☉ |
| Luminosity | 8.233±0.038[1] L☉ |
| Surface gravity (log g) | 4.21±0.14[6] cgs |
| Temperature | 7,220+126 −175[1] K |
| Metallicity [Fe/H] | 0.04[7] dex |
| Age | 498[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The stellar classification of this star was determined to be F0III by A. Cowley and associates (1969),[3] matching an evolved F-type giant star. In contrast, D. R. Palmer and associates (1968) listed it as an A-type main-sequence star with a class of A7V.[4] It is about a half billion years old and is spinning rapidly with a projected rotational velocity of 165.0 km/s, which is giving the star an equatorial bulge that is ~24% wider than the polar radius.[10] The star has 1.5[6] times the mass and 1.8[1] times the mean radius of the Sun. It is radiating over eight times the luminosity of the Sun from its photosphere at an effective temperature of 7,220 K.[1]