HR 9038
Ternary star system in the constellation Cepheus
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HR 9038 is a triple star system located 35 light-years away, in the constellation Cepheus.[1] Component A is a spectroscopic binary system with an orbital period of 7.753 days and a combined stellar classification of K3 V.[10] Component B is a red dwarf star that orbits the primary pair every 290 years.[5]
Apparentmagnitude(V)6.40[2] (6.93 / 7.33)[3]
Apparentmagnitude(V)11.4[5]
SpectraltypeK3 V[6] + K3 V[6] + M2[7]
U−B color index0.70[2]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| HR 9038 A | |
| Right ascension | 23h 52m 25.40913s[1] |
| Declination | +75° 32′ 40.3549″[1] |
| Apparent magnitude (V) | 6.40[2] (6.93 / 7.33)[3] |
| HR 9038 B | |
| Right ascension | 23h 52m 26.31841s[4] |
| Declination | +75° 32′ 42.2862″[4] |
| Apparent magnitude (V) | 11.4[5] |
| Characteristics | |
| Spectral type | K3 V[6] + K3 V[6] + M2[7] |
| U−B color index | 0.70[2] |
| B−V color index | 0.98[2] |
| R−I color index | 0.5 |
| Astrometry | |
| Radial velocity (Rv) | +4.60[8] km/s |
| Proper motion (μ) | RA: 309.900±0.052[1] mas/yr Dec.: 25.334±0.059[1] mas/yr |
| Parallax (π) | 91.7722±0.0425 mas[1] |
| Distance | 35.54 ± 0.02 ly (10.897 ± 0.005 pc) |
| Absolute magnitude (MV) | 6.77 / 7.16 / ?[3] |
| Absolute bolometric magnitude (Mbol) | 6.34 / 6.62 / ?[3] |
| Orbit[9] | |
| Primary | HR 9038 A |
| Name | HR 9038 B |
| Period (P) | 290.0 yr |
| Semi-major axis (a) | 4.14″ |
| Eccentricity (e) | 0.55 |
| Inclination (i) | 49.58° |
| Longitude of the node (Ω) | 93.91° |
| Periastron epoch (T) | 2015.0 |
| Argument of periastron (ω) (secondary) | 134.14° |
| Orbit[6] | |
| Primary | HR 9038 Aa |
| Name | HR 9038 Ab |
| Period (P) | 7.7531 d |
| Eccentricity (e) | 0.0 |
| Inclination (i) | ~60[3]° |
| Periastron epoch (T) | 2420001.264 |
| Argument of periastron (ω) (secondary) | 0.0° |
| Semi-amplitude (K1) (primary) | 39.9 km/s |
| Semi-amplitude (K2) (secondary) | 49.7 km/s |
| Details[3] | |
| HR 9038 Aa | |
| Mass | 0.70 M☉ |
| Radius | 0.69 R☉ |
| Surface gravity (log g) | 4.60 cgs |
| Temperature | 4820 K |
| Metallicity [Fe/H] | -0.29 dex |
| HR 9038 Ab | |
| Mass | 0.67 M☉ |
| Radius | 0.66 R☉ |
| Surface gravity (log g) | 4.62 cgs |
| Temperature | 4620 K |
| Metallicity [Fe/H] | -0.29 dex |
| Other designations | |
| BD+74° 1047, GJ 909, WDS J23524+7533 | |
| HR 9038 A: HD 223778, HIP 117712, HR 9038, SAO 10879 | |
| Database references | |
| SIMBAD | A |
| B | |
