HD 225218
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Andromeda |
| HD 225218 A | |
| Right ascension | 00h 04m 36.58441s |
| Declination | +42° 05′ 33.0865″ |
| Apparent magnitude (V) | 6.16 |
| HD 225218 B | |
| Right ascension | 00h 04m 36.67195s |
| Declination | +42° 05′ 27.8497″ |
| Apparent magnitude (V) | 9.65 |
| Characteristics | |
| A | |
| Spectral type | B9III |
| U−B color index | 0.14 |
| B−V color index | 0.15 |
| A | |
| Evolutionary stage | main sequence |
| Spectral type | F0V |
| Astrometry | |
| HD 225218 A | |
| Radial velocity (Rv) | −8.0 km/s |
| Proper motion (μ) | RA: −10.367±0.266 mas/yr Dec.: −14.491±0.222 mas/yr |
| Parallax (π) | 3.0041±0.3539 mas |
| Distance | approx. 1,100 ly (approx. 330 pc) |
| HD 225218 B | |
| Proper motion (μ) | RA: −12.314±0.015 mas/yr Dec.: −16.129±0.015 mas/yr |
| Parallax (π) | 4.4324±0.0208 mas |
| Distance | 736 ± 3 ly (226 ± 1 pc) |
| Orbit | |
| Primary | Aa |
| Name | Ab |
| Period (P) | 70.12 yr |
| Semi-major axis (a) | 0.165″ |
| Eccentricity (e) | 0.515 |
| Longitude of the node (Ω) | 100.6° |
| Periastron epoch (T) | B2050.0701 |
| Argument of periastron (ω) (secondary) | 295.1° |
| Details | |
| Aa | |
| Mass | 4.02 M☉ |
| Radius | 10.6 R☉ |
| Luminosity | 394 L☉ |
| Surface gravity (log g) | 3.90 cgs |
| Temperature | 7,679 K |
| Rotation | 25 |
| Age | 1.52 years |
| Ab | |
| Mass | 2.01 M☉ |
| B | |
| Mass | 1.34 M☉ |
| Radius | 1.58 R☉ |
| Luminosity | 4.10 L☉ |
| Surface gravity (log g) | 4.17 cgs |
| Temperature | 6,529 K |
| Age | 2.75 Gyr |
| Other designations | |
| BD+41 4933, HD 225218, HIP 365, HR 9105, NSV 15012, SAO 36037, WDS J00046+4206 | |
| Database references | |
| SIMBAD | A |
| B | |
HD 225218 is a quadruple star system in the northern constellation of Andromeda. The primary component, HD 225218 A, is a giant star with a stellar classification of B9III, an apparent magnitude of 6.16, and is a candidate Lambda Boötis star. It has a fainter, magnitude 9.65 companion, HD 225218 B, at an angular separation of 5.2″ along a position angle of 171°. The primary itself has been identified as a binary star system through interferometry, with the two components separated by 0.165″. The pair, HD 225218 Aa and Ab, orbit each other with a period of about 70 years and an eccentricity of 0.515. Component B is has been suspected to itself be a spectroscopic binary, but it is now thought that component A contains a third low-mass star.