HD 39118
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Orion |
| Right ascension | 05h 50m 30.03s |
| Declination | +02° 01′ 28.9″ |
| Apparent magnitude (V) | 5.976 |
| Characteristics | |
| Cool primary | |
| Evolutionary stage | Horizontal branch |
| Spectral type | K0II |
| Apparent magnitude (B) | 6.83±0.015 |
| Apparent magnitude (G) | 5.64 |
| Apparent magnitude (J) | 4.193±0.238 |
| Apparent magnitude (H) | 3.502±0.194 |
| Apparent magnitude (K) | 3.337±0.19 |
| B−V color index | 1.12 |
| Hot secondary | |
| Evolutionary stage | B-type main-sequence star + A-type main-sequence star |
| Spectral type | B7V/B8V + A0V |
| B−V color index | -0.09 |
| Astrometry | |
| Radial velocity (Rv) | 4.24 km/s |
| Proper motion (μ) | RA: 1.097 mas/yr Dec.: -5.161 mas/yr |
| Parallax (π) | 1.47±0.23 mas |
| Distance | 2300+350 −270 ly (707.6+107 −83.3 pc) |
| Absolute magnitude (MV) | –2.53 (–2.3 (primary) + –0.75 (secondary)) |
| Orbit | |
| Primary | Cool primary |
| Companion | Hot secondary |
| Period (P) | 2570±13 d 7.04±0.04 year |
| Semi-major axis (a) | 4.7×108 km 3.14 AU |
| Eccentricity (e) | 0.3±0.007 |
| Details | |
| K-type giant | |
| Mass | 3.3+0.3 −0.27 M☉ |
| Radius | 23.5+3.7 −1.9 R☉ |
| Luminosity | 535 L☉ |
| Surface gravity (log g) | 1.52 cgs |
| Temperature | 4,550 K |
| Metallicity [Fe/H] | -0.34 dex |
| Rotational velocity (v sin i) | 4.19 km/s |
| Age | 257 Myr |
| B-type star | |
| Temperature | 11,300 K |
| Other designations | |
| BD+01 1148, Gaia DR2 3316078695157768448, Gaia DR3 3316078695157768448, HD 39118/39119, HIP 27588, HR 2024, SAO 113198, PPM 149543, TIC 158867386, TYC 120-877-1, GSC 00120-00877, IRAS 05478+0200, 2MASS J05503003+0201290 | |
| Database references | |
| SIMBAD | data |
HD 39118 (HD 39119, HR 2024) is a spectroscopic binary star in the constellation Orion, close to the celestial equator. It is made up from three stars: a cool primary (a K-type giant star) and a hot secondary, which is a binary star formed from a B-type main-sequence star and an A-type main-sequence star. A 2021 estimate derive a distance of 708 parsecs (2,310 ly) to HD 39118, and it is moving away from Earth at a speed of 4.24 km/s. The apparent magnitude is 5.976, making it visible to the naked eye only from dark skies.