Kappa Lyrae

κ Lyrae, Latinized as Kappa Lyrae, is a solitary^[11] star in the northern constellation of Lyra, near the constellation border with Hercules. It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.33.^[2] This object is located approximately 252 light years from the Sun based on parallax,^[1] but is moving closer with a radial velocity of −24 km/s.^[7]

Kappa Lyrae

Location of κ Lyrae (circled)
Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Lyra
Right ascension	18h 19m 51.70908s[1]
Declination	+36° 03′ 52.3691″[1]
Apparent magnitude (V)	4.33[2]
Characteristics
Evolutionary stage	red clump[3]
Spectral type	K2-IIIabCN0.5[4]
U−B color index	+1.17[5]
B−V color index	+1.162±0.013[2]
Variable type	suspected[6]
Astrometry
Radial velocity (Rv)	−24.36±0.13[7] km/s
Proper motion (μ)	RA: −16.75[1] mas/yr Dec.: +41.09[1] mas/yr
Parallax (π)	12.96±0.14 mas[1]
Distance	252 ± 3 ly (77.2 ± 0.8 pc)
Absolute magnitude (MV)	−0.11[2]
Details
Radius	18[7] R☉
Luminosity	127.4[8] L☉
Surface gravity (log g)	2.51[9] cgs
Temperature	4,638[9] K
Metallicity [Fe/H]	+0.13[9] dex
Rotational velocity (v sin i)	5.0[7] km/s
Other designations
κ Lyr, 1 Lyrae, BD+36°3094, HD 168775, HIP 89826, HR 6872, SAO 66869[10]
Database references
SIMBAD	data

This is an aging giant star with a stellar classification of K2-IIIabCN0.5,^[4] with the suffix notation indicating a mild underabundance of cyanogen. Having exhausted the supply of hydrogen at its core, the star has cooled and expanded. It now has 18^[7] times the Sun's girth and is radiating 127^[8] times the luminosity of the Sun at an effective temperature of 4,638 K.^[9] κ Lyrae is a red clump giant, which means it is on the horizontal branch and is generating energy through core helium fusion.^[3] It is a suspected small amplitude variable star.^[6]