| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 00h 49m 26.76537s[1] |
| Declination | −23° 12′ 44.9359″[1] |
| Apparent magnitude (V) | 7.155[2] |
| Characteristics | |
| Spectral type | G8V |
| B−V color index | 0.77 |
| Astrometry | |
| Radial velocity (Rv) | 9.893 ± 0.016[3] km/s |
| Proper motion (μ) | RA: 516.92±0.55[1] mas/yr Dec.: 120.05±0.45[1] mas/yr |
| Parallax (π) | 53.51 ± 0.53 mas[1] |
| Distance | 61.0 ± 0.6 ly (18.7 ± 0.2 pc) |
| Absolute magnitude (MV) | 5.94 |
| Orbit[4] | |
| Primary | HD 4747A |
| Companion | HD 4747B |
| Period (P) | 33.2±0.4 yr |
| Semi-major axis (a) | 10.0±0.2 AU |
| Eccentricity (e) | 0.7317±0.0014 |
| Inclination (i) | 48.0±0.9° |
| Longitude of the node (Ω) | 89.4±1.1° |
| Periastron epoch (T) | JD 2462615±155 |
| Argument of periastron (ω) (secondary) | 267.2±0.5° |
| Semi-amplitude (K1) (primary) | 0.7553+0.0124 −0.0116[5] km/s |
| Details | |
| Mass | 0.81 ± 0.02[3] / ≥0.0440 ± 0.0022[3] M☉ |
| Radius | 0.785 ± 0.018[6] R☉ |
| Luminosity | 0.45 ± 0.02 (log -0.346 ± 0.04)[6] L☉ |
| Surface gravity (log g) | 4.48 ± 0.10[7] cgs |
| Temperature | 5316 ± 50[7] K |
| Metallicity [Fe/H] | -0.21 ± 0.05[7] dex |
| Age | 0.1-7.3 (weakly constrained)[3] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 4747 is a star that lies approximately 61 light-years away in the constellation of Cetus. The star is a low-amplitude spectroscopic binary, with the secondary being a directly detected brown dwarf.
van Leeuwen2007 was invoked but never defined (see the help page).Sahlmann2011 was invoked but never defined (see the help page).Xuan2022 was invoked but never defined (see the help page).Crepp2016 was invoked but never defined (see the help page).Valenti2005 was invoked but never defined (see the help page).Santos2005 was invoked but never defined (see the help page).