Kappa Lyrae
Star in the constellation Lyra
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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]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| 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]