4 Cassiopeiae
Star in the constellation Cassiopeia
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4 Cassiopeiae is a red giant in the northern constellation of Cassiopeia,[10] located approximately 790 light-years away from the Sun.[4] It is visible to the naked eye as a faint, red-hued star with a baseline apparent visual magnitude of 4.96.[3] At the distance of this system, its visual magnitude is diminished by an extinction of 0.56 due to interstellar dust.[11] This system is moving closer to the Earth with a heliocentric radial velocity of −39 km/s.[7]
A light curve for 4 Cassiopeiae, plotted from Hipparcos data.[1] The assumed period is from Koen and Eyer (2002).[2] | |
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Cassiopeia[3] |
| Right ascension | 23h 24m 50.26237s[4] |
| Declination | +62° 16′ 58.1094″[4] |
| Apparent magnitude (V) | 4.96[3] (4.95 – 5.00)[5] |
| Characteristics | |
| Evolutionary stage | AGB[6] |
| Spectral type | M2− IIIab[3] |
| B−V color index | 1.676±0.010[3] |
| Variable type | suspected[5] |
| Astrometry | |
| Radial velocity (Rv) | −38.99±0.23[7] km/s |
| Proper motion (μ) | RA: +12.29[4] mas/yr Dec.: −12.44[4] mas/yr |
| Parallax (π) | 4.15±0.21 mas[4] |
| Distance | 790 ± 40 ly (240 ± 10 pc) |
| Absolute magnitude (MV) | −1.94[3] |
| Details | |
| Mass | 2.3[8] M☉ |
| Radius | 78[9] R☉ |
| Luminosity | 1,419[9] L☉ |
| Temperature | 4,000[9] K |
| Other designations | |
| 4 Cas, NSV 14549, BD+61°2444, FK5 882, HD 220652, HIP 115590, HR 8904, SAO 20614, WDS J23248+6217A[10] | |
| Database references | |
| SIMBAD | data |
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An evolved red giant star, currently on the asymptotic giant branch,[6] 4 Cassiopeiae has a stellar classification of M2− IIIab.[3] It is a suspected variable star of unknown type with a brightness that varies from visual magnitude 4.95 down to 5.00.[5]
Multiple star catalogues list a number of companions to 4 Cassiopeiae, all unrelated stars at different distances.[12] As of 2011, the magnitude 9.88 component B lay at an angular separation of 96.10″ along a position angle of 226° relative to the primary. Components C, E, F, and G are all fainter and more than two arc-minutes from 4 Cassiopeiae, and components C and G are themselves close doubles.[13]
4 Cassiopeiae is 40' north of the open cluster Messier 52, near the constellation border with Cepheus, although it is not a member of the cluster.[14]