Lambda Cassiopeiae , Latinized from λ Cassiopeiae, is a binary star system, in the northern constellation of Cassiopeia . The system has a combined apparent magnitude of +4.74, making it faintly visible to the naked eye. With an annual parallax shift of 8.64 mass ,[ 2] it is approximately 380 light years from Earth . The system is moving closer to the Sun with a radial velocity of −12 km/s.[ 6]
Quick Facts Observation data Epoch J2000.0 Equinox J2000.0, Constellation ...
λ Cassiopeiae
Observation dataEpoch J2000.0 Equinox J2000.0
Constellation
Cassiopeia [ 1]
Right ascension
00h 31m 46.35935s [ 2]
Declination
+54° 31′ 20.2257″ [ 2]
Apparent magnitude (V)
4.772[ 3] (5.33 / 5.62)[ 4]
Characteristics
Spectral type
B8 Vnn[ 1]
U−B color index
−0.35[ 5]
B−V color index
−0.10[ 5]
Astrometry Radial velocity (Rv ) −12.20± 1.3[ 6] km/s Proper motion (μ) RA: +41.20± 0.29[ 2] mas /yr Dec.: −16.54± 0.35[ 2] mas /yr Parallax (π)8.64± 0.43 mas [ 2] Distance 380 ± 20 ly (116 ± 6 pc ) Absolute magnitude (MV )−0.57[ 1]
Orbit [ 4] Period (P) 245.70± 35.96 yr Semi-major axis (a) 0.448± 0.028 ″Eccentricity (e) 0.689± 0.119Inclination (i) 53.6± 5.2° Longitude of the node (Ω) 17.6± 9.6° Periastron epoch (T) 2025 .54± 4.56Argument of periastron (ω) (secondary) 301.0± 2.6°
Details λ Cas A Mass 2.9+0.45 −0.40 [ 7] M ☉ Radius 3.50[ 8] R ☉ Luminosity 255[ 1] L ☉ Surface gravity (log g ) 4.0± 0.25[ 7] cgs Temperature 12,000± 1,000[ 7] K Rotational velocity (v sin i )253[ 9] km/s Age 58+104 −48 [ 7] Myr
Other designations λ Cas , 14 Cassiopeiae , BD +53°82 , HD 2772 , HIP 2505 , HR 123 , SAO 21489 , ADS 434 , CCDM J00318+5431
Database references SIMBAD λ Cas λ Cas A λ Cas B
Close
λ Cassiopeiae in optical light
Both components are blue-white B-type main-sequence stars . The brighter member, component A, has an apparent magnitude of +5.5, while its companion, component B, has an apparent magnitude of +5.8. The two stars are separated by 0.6 arcseconds and complete one orbit around their common centre of mass about once every 250 years.[ 4] The primary displays an infrared excess , possibly due to a debris disk or other orbiting material.[ 8]