S Cephei

S Cephei (S Cep), also designated as HD 206362, is a carbon star and Mira-type variable in the constellation Cepheus. Based on the measurement of its annual parallax by the Gaia satellite, the star is approximately ~1,590 ly (~490 pc) away from Earth.

A visual band light curve for S Cephei, plotted from ASAS-SN data^[8]

S Cephei

S Cephei, as seen by WISE (false colour infrared)
Observation data Epoch J2000      Equinox J2000
Constellation	Cepheus
Right ascension	21h 35m 12.8233s[1]
Declination	+78° 37′ 28.185″[1]
Apparent magnitude (V)	6.6 - 12.5[2]
Characteristics
Evolutionary stage	AGB[3]
Spectral type	C7,3e[4]
Variable type	Mira[2]
Astrometry
Proper motion (μ)	RA: 8.278[1] mas/yr Dec.: 0.748[1] mas/yr
Parallax (π)	2.0452±0.0697 mas[1]
Distance	1,590 ± 50 ly (490 ± 20 pc)
Details
Mass	5.4[5] M☉
Radius	254[6] R☉
Luminosity	5,417[6] L☉
Surface gravity (log g)	3.61[5] cgs
Temperature	4,032[5] K
Metallicity [Fe/H]	−0.54[5] dex
Other designations
BD+77°827, HD 206362, HIP 106583, SAO 10100[7]
Database references
SIMBAD	data

S Cephei is a carbon star of spectral type C7.3e.^[9] It is also a Mira-type variable star whose apparent magnitude varies from 6.6 to 12.5 in the form of a pulsation over a period of 484 days.^[2] Its variability was discovered by Karl Hencke in 1858.^[10]

See also

• Mu Cephei
• ST Cephei