CL Draconis

CL Draconis is a single^[10] star in the northern circumpolar constellation of Draco. It can be viewed with the naked eye, having an apparent visual magnitude of 4.96.^[2] The distance to this star, as determined from its annual parallax shift of 29.9 mas,^[1] is 109 light years. It is moving closer to the Earth with a heliocentric radial velocity of −11 km/s.^[5] The star has a relatively high proper motion, traversing the celestial sphere at the rate of 0.185″/yr.^[11]

CL Draconis

CL Draconis (circled), with the obsolete constellation Quadrans Muralis in the background.
Observation data Epoch J2000      Equinox J2000
Constellation	Draco
Right ascension	15h 57m 47.44180s[1]
Declination	+54° 44′ 59.1428″[1]
Apparent magnitude (V)	4.96[2]
Characteristics
Spectral type	F0 IV[3]
B−V color index	0.269±0.008[2]
Variable type	δ Sct[4]
Astrometry
Radial velocity (Rv)	−11.0±4.2[5] km/s
Proper motion (μ)	RA: −151.643[1] mas/yr Dec.: +107.519[1] mas/yr
Parallax (π)	29.9305±0.1368 mas[1]
Distance	109.0 ± 0.5 ly (33.4 ± 0.2 pc)
Absolute magnitude (MV)	2.33[2]
Details
Mass	1.68±0.01[6] M☉
Luminosity	10.2+0.2 −0.3[6] L☉
Surface gravity (log g)	4.04±0.14[7] cgs
Temperature	7,439±253[7] K
Metallicity [Fe/H]	0.04±0.10[8] dex
Rotational velocity (v sin i)	165[6] km/s
Age	643[7] Myr
Other designations
CL Dra, AG+54° 1023, BD+55° 1793, FK5 595, HD 143466, HIP 78180, HR 5960, SAO 29727[9]
Database references
SIMBAD	data

Based upon a stellar classification of F0 IV,^[3] this is an aging F-type subgiant star that has consumed the hydrogen at its core. It is spinning rapidly with a projected rotational velocity of 165 km/s,^[6] giving it an oblate shape with an equatorial bulge that is estimated to be 8% larger than the polar radius.^[12]

caption=Visual band light curves for CL Draconis, adapted from DuPuy and Burgoyne (1983)^[13]

CL Draconis is a Delta Scuti variable, changing brightness with an amplitude of 0.010 magnitude over a period of 1.83 hours.^[14] CL Dra has 1.68^[6] times the mass of the Sun and is radiating 10.2^[6] times the Sun's luminosity from its photosphere at an effective temperature of 7,439 K.^[7]

It was transferred from Draco to Quadrans Muralis. Later when the International Astronomical Union officially recognised constellations, Quadrans Muralis became obsolete, so this star was moved back to Draco.