R Canum Venaticorum

R Canum Venaticorum is a Mira variable star in the constellation Canes Venatici. It ranges between magnitudes 6.5 and 12.9 over a period of approximately 329 days.^[3] It is too faint to be seen with the naked eye, but when it is near its maximum brightness it can be seen with binoculars.

R Canum Venaticorum

The visual band light curve of R Canum Venaticorum, from AAVSO data[1]
Observation data Epoch J2000      Equinox J2000
Constellation	Canes Venatici
Right ascension	13h 48m 57.0416s[2]
Declination	+39° 32′ 33.174″[2]
Apparent magnitude (V)	6.5 - 12.9[3]
Characteristics
Evolutionary stage	AGB[4]
Spectral type	M5.5e-M9e[3]
U−B color index	+0.41[5]
B−V color index	+1.22[5]
Variable type	Mira[3]
Astrometry
Radial velocity (Rv)	−6.80[6] km/s
Proper motion (μ)	RA: −1.115[2] mas/yr Dec.: −5.148[2] mas/yr
Parallax (π)	2.1711±0.1262 mas[2]
Distance	1,500 ± 90 ly (460 ± 30 pc)
Details
Mass	2.26[7] M☉
Radius	664[7] R☉
Luminosity	29,251[8] L☉
Surface gravity (log g)	2.19[9] cgs
Temperature	3,108[8] K
Metallicity [Fe/H]	−0.25[9] dex
Other designations
R CVn, SAO 63763, GSC 03027-00252, BD+40°2694, HD 120499, DO 14814, GC 18671, HIP 67410, HR 5199
Database references
SIMBAD	data

Thomas E. Espin discovered this variable star in 1888.^[10] It appeared with its variable star designation, R Canum Venaticorum in Annie Jump Cannon's 1907 work Second Catalogue of Variable Stars.^[11]

Having exhausted its core helium, R Canum Venaticorum is on the asymptotic giant branch, producing energy from concentric hydrogen and helium shells.^[4]