Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Andromeda |
Right ascension | 00h 50m 18.26563s[2] |
Declination | +45° 00′ 08.1439″[2] |
Apparent magnitude (V) | 6.13[3] |
Characteristics | |
Spectral type | A3VpSiSrCrEuKsn[4] |
B−V color index | 0.043±0.004[3] |
Variable type | α2 CVn[5] |
Astrometry | |
Radial velocity (Rv) | 1.60[6] km/s |
Proper motion (μ) | RA: 65.353[2] mas/yr Dec.: 4.133[2] mas/yr |
Parallax (π) | 9.3224 ± 0.0916 mas[2] |
Distance | 350 ± 3 ly (107 ± 1 pc) |
Absolute magnitude (MV) | 1.18[7] |
Details | |
Mass | 2.24±0.09[7] M☉ |
Radius | 2.36±0.12[8] R☉ |
Luminosity | 34.9±4.3[8] L☉ |
Surface gravity (log g) | 4.12±0.09[7] cgs |
Temperature | 9,135±400[8] K |
Rotation | 2.5616[7] days |
Rotational velocity (v sin i) | 33[4] km/s |
Age | 77[9] Myr |
Other designations | |
Database references | |
SIMBAD | data |
HD 4778, also known as HR 234 and GO Andromedae, is a variable star in the constellation Andromeda. Its magnitude varies by 0.04 magnitudes from the median of 6.12 with a period of approximately 2.55 days.[11] The star is located 350 light years away, as determined from its annual parallax shift of 9.32 mas.[2]
This is an Ap star with a stellar classification of A3VpSiSrCrEuKsn,[4] showing chemical peculiarities in its spectrum from strontium, chromium, and europium.[12] It is an Alpha2 Canum Venaticorum variable[5] with a magnetic field that varies across the range +1,400 to −1,100 G.[13] This rotation-modulated variability allows direct determination of the rotation rate of 2.5616 days.[7]
HD 4778 has 2.24[7] times the mass of the Sun and 2.36[8] times the Sun's radius. The star is radiating 35[8] times the Sun's luminosity from its photosphere at an effective temperature of 9,375 K.[7] It is about 77[9] million years old.