HD 28736
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Taurus |
| HD 28736 A | |
| Right ascension | 04h 32m 04.80859s |
| Declination | +05° 24′ 36.1482″ |
| Apparent magnitude (V) | 6.352 |
| HD 28736 C | |
| Right ascension | 04h 33m 56.59566s |
| Declination | +05° 37′ 23.5351″ |
| Characteristics | |
| Spectral type | (F5V + L9-T1) + L0/1 |
| B−V color index | +0.431 |
| Astrometry | |
| HD 28736 A | |
| Radial velocity (Rv) | 39.5813 ± 0.0216 km/s |
| Proper motion (μ) | RA: 112.174 mas/yr Dec.: 7.756 mas/yr |
| Parallax (π) | 23.1089±0.0278 mas |
| Distance | 141.1 ± 0.2 ly (43.27 ± 0.05 pc) |
| Absolute magnitude (MV) | 3.18 |
| HD 28736 C | |
| Proper motion (μ) | RA: 107.173 mas/yr Dec.: 7.595 mas/yr |
| Parallax (π) | 22.6203 ± 0.4505 mas |
| Distance | 144 ± 3 ly (44.2 ± 0.9 pc) |
| Orbit | |
| Primary | HD 28736 A |
| Companion | HD 28736 B |
| Period (P) | 60+30 −16 yr |
| Semi-major axis (a) | 0.37" (17+5 −4 AU) |
| Eccentricity (e) | 0.36+0.37 −0.25 |
| Inclination (i) | 95.3+3.9 −2.1° |
| Orbit | |
| Primary | HD 28736 A |
| Companion | HD 28736 C |
| Semi-major axis (a) | 1837" (79000 AU) |
| Details | |
| HD 28736 A | |
| Mass | 1.40±0.05 M☉ |
| Surface gravity (log g) | 4.3±0.2 cgs |
| Temperature | 6655±125 K |
| Metallicity [Fe/H] | 0.13±0.05 dex |
| Rotational velocity (v sin i) | 45.6±1.8 km/s |
| Age | 650±100 Myr |
| HD 28736 B | |
| Mass | 24+6 −4 MJup |
| Surface gravity (log g) | 4.5 cgs |
| Temperature | 1300±50 K |
| HD 28736 C | |
| Mass | 73±7 MJup |
| Radius | 0.10 R☉ |
| Luminosity | 2.40+0.23 −0.21×10−4 L☉ |
| Other designations | |
| HD 28736 AB: 58 G. Tauri, AG+05°479, BD+05°674, Gaia DR3 3285426613077584384, GC 5531, HD 28736, HIP 21152, HR 1436, SAO 111879, PPM 147652, TIC 452767166, TYC 90-33-1, GSC 00090-00033, 2MASS J04320481+0524359 | |
| HD 28736 C: Gaia DR3 3285527699426683264, 2MASS J04335658+0537235, WISE J043356.65+053723.5 | |
| Database references | |
| SIMBAD | HD 28736 |
| B | |
| C | |
HD 28736 (HIP 21152, HR 1436) is a triple star system in the constellation of Taurus. It is composed of an F-type main-sequence star, an orbiting low-mass brown dwarf or giant planet, and a high-mass brown dwarf or low-mass star. Located some 141 light-years (43 parsecs) away according to Gaia DR3 parallax measurements, it is a member of the Hyades cluster, moving away from Earth at a heliocentric radial velocity of 39.58 km/s. With an apparent magnitude of 6.352, it is near the limit for naked eye visibility under dark skies.