Alpha Lyncis
Star in the constellation Lynx
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Alpha Lyncis (α Lyn, α Lyncis) is the brightest star in the northern constellation of Lynx with an apparent magnitude of +3.13.[4] Unusually, it is the only star in the constellation that has a Bayer designation.[10] Based upon parallax measurements, this star is located about 220 light-years (67 parsecs) from the Earth.[1]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lynx |
| Right ascension | 09h 21m 03.30021s[1] |
| Declination | +34° 23′ 33.2134″[1] |
| Apparent magnitude (V) | +3.14[2] |
| Characteristics | |
| Evolutionary stage | Giant star |
| Spectral type | K7 III[3] |
| U−B color index | +1.95[4] |
| B−V color index | +1.55[4] |
| Astrometry | |
| Radial velocity (Rv) | 37.15[5] km/s |
| Proper motion (μ) | RA: −218.723 mas/yr[1] Dec.: 16.555 mas/yr[1] |
| Parallax (π) | 14.7±0.18 mas[1] |
| Distance | 220.7+2.9 −2.6 ly (67.7+0.9 −0.8 pc)[6] |
| Absolute bolometric magnitude (Mbol) | –2.32 ± 0.13[7] |
| Details | |
| Mass | 1.52±0.077[8] M☉ |
| Radius | 58.15+0.73 −0.75[9] R☉ |
| Luminosity | 621.1±15.8[8] L☉ |
| Surface gravity (log g) | 1.06±0.04[8] cgs |
| Temperature | 3,881±20[8] K |
| Metallicity [Fe/H] | −0.26±0.05[8] dex |
| Rotational velocity (v sin i) | 6.4[5] km/s |
| Age | 1.4[10] Gyr |
| Other designations | |
| 40 Lyncis, HR 3705, HD 80493, BD+35°1979, HIP 45860, SAO 61414, FK5 352, NSV 4456, GC 12880[11] | |
| Database references | |
| SIMBAD | data |
Characteristics
This is a red giant star that has exhausted the hydrogen at its core and has evolved away from the main sequence. It has expanded to about 58 times the Sun's radius[9] and it is emitting roughly 621 times the luminosity of the Sun. The estimated effective temperature of the star's outer envelope is 3,881 K,[8] which is lower than the Sun's effective temperature of 5,778 K, and is giving Alpha Lyncis a red-orange hue that is characteristic of late K-type stars.[12]
Alpha Lyncis is a suspected small-amplitude red variable star[13] that changes apparent magnitude from +3.17 up to +3.12.[14] This variability pattern typically occurs in stars that have developed an inert carbon core surrounded by a helium-fusing shell, and suggests that Alpha Lyncis is starting to evolve into a Mira variable.[10]