T Cephei
Star in the constellation Cepheus
From Wikipedia, the free encyclopedia
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] When it is near its maximum brightness, it is faintly visible to the naked eye under good observing conditions.
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[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 | |
| T Cephei, HR 8113, HD 202012, HIP 104451, BD+67°1291, GC 29611, SAO 19229, GSC 04460-02400 | |
| Database references | |
| SIMBAD | data |
Vitold Ceraski announced his discovery that the star is a variable star, in 1879.[12] It appeared with its variable star designation, T Cephei, in Annie Jump Cannon's 1907 publication Second catalogue of variable stars.[13] 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.