R Serpentis

R Serpentis is a Mira variable type star in the equatorial constellation of Serpens. It ranges between apparent magnitude 5.16 and 14.4, and spectral types M5e to M8e, over a period of 356.41 days.^[4][11] When it is near maximum brightness, it can be seen with the naked eye under excellent observing conditions. The variability of this star was discovered in 1826 by Karl Ludwig Harding.^[12]

R Serpentis

The visual band light curve of R Serpentis, from AAVSO data[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Serpens[2]
Right ascension	15h 50m 41.73245s[3]
Declination	+15° 08′ 01.0810″[3]
Apparent magnitude (V)	5.2 - 14.4[4]
Characteristics
Evolutionary stage	AGB[5]
Spectral type	M5-8e[6]
B−V color index	1.500±0.510[2]
Variable type	Mira[4]
Astrometry
Radial velocity (Rv)	23.8±0.8[7] km/s
Proper motion (μ)	RA: +2.387[3] mas/yr Dec.: −36.699[3] mas/yr
Parallax (π)	3.5110±0.2966 mas[3]
Distance	930 ± 80 ly (280 ± 20 pc)
Details
Mass	3.6[8] M☉
Radius	79[9] R☉
Luminosity	758[9] L☉
Surface gravity (log g)	1.55[8] cgs
Temperature	3,413[9] K
Other designations
R Ser, BD+15°2918, HD 141850, HIP 77615, HR 5894, SAO 101771[10]
Database references
SIMBAD	data