48 Cassiopeiae
Triple star system in the constellation Cassiopeia
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48 Cassiopeiae is a triple star[11][7] system in the northern constellation of Cassiopeia. It is visible to the naked eye with a combined apparent visual magnitude of 4.49.[1] With an annual parallax shift of 28.36±0.44 mas as seen from Earth's orbit, it is located approximately 115 light years away.[2] The system is moving closer with a heliocentric radial velocity of −12.4 km/s.[5]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cassiopeia[1] |
| Right ascension | 02h 01m 57.45035s[2] |
| Declination | +70° 54′ 25.2902″[2] |
| Apparent magnitude (V) | 4.49[1] |
| Characteristics | |
| Spectral type | A3 Va[3] (A2 V + F2 V)[4] |
| B−V color index | 0.164±0.008[1] |
| Astrometry | |
| Radial velocity (Rv) | −12.4[5] km/s |
| Proper motion (μ) | RA: −55.69[2] mas/yr Dec.: −8.71[2] mas/yr |
| Parallax (π) | 28.36±0.44 mas[2] |
| Distance | 115 ± 2 ly (35.3 ± 0.5 pc) |
| Absolute magnitude (MV) | 1.75[1] |
| Orbit[6] | |
| Primary | 48 Cas A |
| Name | 48 Cas B |
| Period (P) | 61.14±0.05 yr |
| Semi-major axis (a) | 0.614±0.002″ |
| Eccentricity (e) | 0.355±0.001 |
| Inclination (i) | 16.7±0.9° |
| Longitude of the node (Ω) | 48.2±3.2° |
| Periastron epoch (T) | 1964.35±0.09 |
| Argument of periastron (ω) (secondary) | 19.5±3.6° |
| Details | |
| 48 Cas A | |
| Mass | 1.93[7] M☉ |
| Luminosity | 17.8+0.6 −1.2[8] L☉ |
| Surface gravity (log g) | 4.47[9] cgs |
| Temperature | 8,538±290[9] K |
| Metallicity [Fe/H] | −0.4[5] dex |
| Rotational velocity (v sin i) | 61[8] km/s |
| Age | 376[9] Myr |
| 48 Cas B | |
| Mass | 1.17[7] M☉ |
| Other designations | |
| A Cassiopeiae, 48 Cas, BD+70°153, HD 12111, HIP 9480, HR 575, SAO 4554, ADS 1598, CCDM J02020+7054, WDS J02020+7054AB[10] | |
| Database references | |
| SIMBAD | data |
The primary component, designated 48 Cassiopeiae A, is a white A-type main-sequence star with a stellar classification of A2 V[4] and an apparent magnitude of +4.65.[12] It has a companion, component B, which is an F-type main-sequence star of class F2 V[4] and an apparent magnitude of +6.74.[12] This pair orbit around their common centre of mass once every 61.1 years.[6] They have a semimajor axis of 0.614 arcseconds and an eccentricity of 0.355.[6] A third companion, component C, is a magnitude 13.20[12] star located at an angular separation of 23.16 arcseconds as of 2014, or at least 816.5 AU away.[7]
48 Cassiopeiae also has the Bayer designation A Cassiopeiae, the only star with a Latin letter designation in the constellation.[13]