T Cephei
Region of NGC 7023, T Cephei is marked with a green arrow Credit: NASA, ESA and Digitized Sky Survey 2 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 21h 09m 31.78348s |
| Declination | +68° 29′ 27.2311″ |
| Apparent magnitude (V) | 5.2 - 11.3 |
| Characteristics | |
| Evolutionary stage | AGB |
| Spectral type | M6-9e |
| U−B color index | +0.33 |
| B−V color index | +1.49 |
| Variable type | Mira |
| Astrometry | |
| Radial velocity (Rv) | −8.03 km/s |
| Proper motion (μ) | RA: −44.210 mas/yr Dec.: −44.921 mas/yr |
| Parallax (π) | 5.4400±0.3476 mas |
| Distance | 600 ± 40 ly (180 ± 10 pc) |
| Details | |
| Mass | 0.55 M☉ |
| Radius | 329+70 −50 R☉ |
| Luminosity | 5,700 L☉ |
| Temperature | 2,400 - 3,347 K |
| Other designations | |
| T Cephei, HR 8113, HD 202012, HIP 104451, BD+67°1291, GC 29611, SAO 19229, GSC 04460-02400 | |
| Database references | |
| SIMBAD | data |
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. When it is near its maximum brightness, it is faintly visible to the naked eye under good observing conditions.
Vitold Ceraski announced his discovery that the star is a variable star, in 1879. It appeared with its variable star designation, T Cephei, in Annie Jump Cannon's 1907 publication Second catalogue of variable stars. 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, the asymptotic giant branch phase, blowing off its own atmosphere to form a white dwarf in a distant future.