| Observation data Epoch J2000.0 Equinox J2000.0 |
|
|---|---|
| Constellation | Orion |
| Right ascension | 05h 46m 34.91s [1] |
| Declination | +01° 10′ 05.5″ [1] |
| Apparent magnitude (V) | +5.94 / +13.35 |
| Characteristics | |
| Spectral type | G4IV / M3.0V |
| U−B color index | ? / ? |
| B−V color index | 0.773 / 0.46 |
| Variable type | none / ? |
| Astrometry | |
| Radial velocity (Rv) | +28.9 km/s |
| Proper motion (μ) | RA: -79.12 ± 0.48 [1] mas/yr Dec.: -141.84 ± 0.35 [1] mas/yr |
| Parallax (π) | 25.46 ± 0.40[1] mas |
| Distance | 128 ± 2 ly (39.3 ± 0.6 pc) |
| Absolute magnitude (MV) | +2.81 / +10.23 |
| Details | |
| Mass | 1.48[2] / ? M☉ |
| Radius | 2.82 / ? R☉ |
| Luminosity | 5.90 / ? L☉ |
| Temperature | 5370 / ? K |
| Metallicity | 0.29 ± 0.05 [Fe/H] |
| Rotation | 34.5 / ? |
| Age | ~3700 million years |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 38529 (also known as HR 1988) is a binary star approximately 128 light-years away in the constellation of Orion.
Contents |
HD 38529 A is a yellow subgiant star, which has also been classified as a main sequence dwarf of spectral type G4V. It is about 40% more massive than our Sun. Two substellar companions are known in orbit around this star, including one with a mass above the deuterium fusion limit that is often used as the dividing line between giant planets and brown dwarfs. There is a debris disk located at least 86 astronomical units from the star.[3]
In 2002, the planet HD 38529 b was discovered orbiting the star HD 38529 A by Debra Fischer who used Doppler spectroscopy.[4] It has mass 78% that of Jupiter and orbits very close to the star, just beyond the distance limit for hot Jupiters. One year later, a massive superjovian HD 38529 c was found orbiting at 3.68 AU with a minimum mass of 12.7 Jupiter masses.[5] Astrometric measurements from the Hipparcos satellite gave a best fit inclination of 160° and a true mass 37 times that of Jupiter, turning this planet into a brown dwarf.[6] Further study of the system using Hubble Space Telescope astrometry revised the mass of HD 38529 c downwards to 17.7 Jupiter masses and suggested the presence of an additional planet, orbiting in the gap between HD 38529 b and c.[2]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity |
|---|---|---|---|---|
| b | >(0.92 ± 0.043) MJ | 0.131 ± 0.0015 | 14.3104 ± 0.05 | 0.248 ± 0.0007 |
| d (unconfirmed) | >(0.17 ± 0.06) MJ | 0.75 ± 0.14 | 193.9 ± 2.9 | 0.23 ± 0.13 |
| c | 17.7+1.7 −1.4 MJ |
3.695 ± 0.043 | 2134.76 ± 0.40 | 0.36 ± 0.05 |
| Debris disk | >86 AU | |||
HD 38529 B is a common proper motion stellar companion to HD 38529 A at a projected distance of about 12042 AU. The star is a red dwarf of spectral type M3.0V.[7]