YZ Cassiopeiae

From Wikipedia, the free encyclopedia
Jump to: navigation, search
YZ Cas
Observation data
Epoch J2000      Equinox J2000
Constellation Cassiopeia
Right ascension 00h 45m 39.0777s[1]
Declination +74° 59′ 17.063″[1]
Apparent magnitude (V) 5.6/6.0[2]
Spectral type A2IV[1]
B−V color index 0.067[3]
Variable type Algol variable
Radial velocity (Rv) +8.9±0.9[1] km/s
Proper motion (μ) RA: -14.93[1] mas/yr
Dec.: -21.86[1] mas/yr
Parallax (π) 11.24 ± 0.55[1] mas
Distance 290 ± 10 ly
(89 ± 4 pc)
Companion TYC 4307-2168-1
Period (P) 86 580[4] yr
Other designations
21 Cassiopeiae, HR 192, BD+74 27, HD 4161, SAO 4216, HIP 3572, GC 891, ADS 624 A, CCDM J00457+7459[1]

YZ Cassiopeiae (21 Cas) is a star system 89 parsecs (290 light years) away from Earth, in the constellation Cassiopeia.[1] It comprises three stars: an eclipsing Algol-type binary and a visually fainter star about 3000 AU distant.[4]

The primary star in the YZ Cassiopeiae system is a white subgiant (main sequence) star of spectral type A1m[3] and 2.31 solar masses[4] (M) with a less massive main sequence dwarf star of type F2V[3] and 1.35 M.[4] The apparent magnitude of the eclipsing binary varies from 5.65 to 6.05[3] with a period of 4.4672 days.[4] Combined, they appear to have a spectral type of A2IV.[4]

The binary has a dimmer (magnitude 9.7 according to Norton,[2] or 10.5 by SIMBAD) companion of 0.8 M[4] orbiting with a period of about 86 580 years.[4]


  1. ^ a b c d e f g h i j "SIMBAD query result: V* YZ Cas -- Eclipsing binary of Algol type". Centre de Données astronomiques de Strasbourg. Retrieved 2008-09-05. 
  2. ^ a b Norton, Arthur P. (1973). Norton's Star Atlas. p. 118. ISBN 0-85248-900-5. 
  3. ^ a b c d Jerzy M. Kreiner, Chun-Hwey Kim, Il-Seong Nha. YZ CAS: Atlas of O-C Diagrams of Eclipsing Binary Stars
  4. ^ a b c d e f g h i Tokovinin 1997-1999. J/A+AS/124/75. Multiple star catalogue (MSC)

Coordinates: Sky map 00h 45m 39.0777s, +74° 59′ 17.063″