T Cephei is a Mira variable star in the constellation Cepheus. Located approximately 600 light-years (180 parsecs) distant, it varies between magnitudes 5.2 and 11.3 over a period of around 388 days.[9][2]
Region of NGC 7023, with T Cephei marked on the full-size image Credit: NASA, ESA and Digitized Sky Survey 2 | |
Observation data Epoch J2000 Equinox J2000 | |
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Constellation | Cepheus |
Right ascension | 21h 09m 31.78348s[1] |
Declination | +68° 29′ 27.2311″[1] |
Apparent magnitude (V) | 5.2 - 11.3[2] |
Characteristics | |
Evolutionary stage | AGB[3] |
Spectral type | M6-9e[4] |
U−B color index | +0.33[5] |
B−V color index | +1.49[5] |
Variable type | Mira[3] |
Astrometry | |
Radial velocity (Rv) | −8.03[6] km/s |
Proper motion (μ) | RA: −44.210[1] mas/yr Dec.: −44.921[1] mas/yr |
Parallax (π) | 5.4400 ± 0.3476 mas[1] |
Distance | 600 ± 40 ly (180 ± 10 pc) |
Details | |
Mass | 0.55[7] M☉ |
Radius | 329+70 −50[8] R☉ |
Luminosity | 5,700[9] L☉ |
Temperature | 2,400[9] - 3,347[10] K |
Other designations | |
Database references | |
SIMBAD | data |
T Cephei is a red giant of spectral type M6-9e with an effective temperature 2,400 K, a radius of 329 R☉, a mass of 0.55 M☉, and a luminosity of 5,700 L☉. If it were in the place of the Sun, its photosphere would at least engulf the orbit of Mars. This star is believed to be in a late stage of its life, blowing off its own atmosphere to form a white dwarf in a distant future.