TZ Cassiopeiae

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TZ Cassiopeiae
Observation data
Epoch J2000      Equinox J2000
Constellation Cassiopeia
Right ascension 23h 52m 56s
Declination 61° 47′ 22″
Apparent magnitude (V) +8.86 - +10.5[1]
Spectral type M3Iab:
U−B color index 2.43
B−V color index 2.57
Variable type Lc[1]
Radial velocity (Rv) -54.28 km/s
Proper motion (μ) RA: −2.77 mas/yr
Dec.: −3.10 mas/yr
Parallax (π) 0.39 ± 0.76 mas
Distance 2,400[2] pc
Absolute magnitude (MV) -5.98[3]
Mass 15[4] M
Radius 800[3] R
Luminosity 98,000[3] L
Surface gravity (log g) -0.1[3] cgs
Temperature 3600[3] K
Other designations
HIP 117763, SAO 20192, AAVSO 2348+60
Database references
SIMBAD TZ Cas data

TZ Cassiopeaie (TZ Cas, HIP 117763, SAO 20912) is a variable star in the constellation Cassiopeia with an apparent magnitude of around +9. It is approximately 4,500 light-years away from Earth. The star is a red supergiant star with a spectrum type of M3 and a temperature of 3600 Kelvin. Currently, it packs 15 solar masses within itself.

TZ Cassiopeaie is a slow irregular variable star with possible periods of 290, 2,800, and 3,100 days.[5] It is approximately 98,000 times the luminosity of the Sun, and it is 800 times bigger than the Sun.


  1. ^ a b Bibcode2011JAVSO..39....1P
  2. ^ Mauron, Nicolas; Josselin, Eric (2010). "The mass-loss rates of red supergiants and the de Jager prescription". arXiv:1010.5369v1 [astro-ph.SR]. 
  3. ^ a b c d e Levesque, E. M.; Massey, P.; Olsen, K. A. G.; Plez, B.; Josselin, E.; Maeder, A.; Meynet, G. (2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not as Cool as We Thought". The Astrophysical Journal 628 (2): 973. arXiv:astro-ph/0504337. Bibcode:2005ApJ...628..973L. doi:10.1086/430901.  edit
  4. ^ Josselin, E.; Plez, B. (2007). "Atmospheric dynamics and the mass loss process in red supergiant stars". Astronomy and Astrophysics 469 (2): 671. doi:10.1051/0004-6361:20066353.  edit
  5. ^ Kiss, L. L.; Szabó, G. M.; Bedding, T. R. (2006). "Variability in red supergiant stars: Pulsations, long secondary periods and convection noise". Monthly Notices of the Royal Astronomical Society 372 (4): 1721. arXiv:astro-ph/0608438. Bibcode:2006MNRAS.372.1721K. doi:10.1111/j.1365-2966.2006.10973.x.  edit