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Variable star in the constellation Lynx From Wikipedia, the free encyclopedia
Y Lyncis is a semiregular variable star in the constellation Lynx. It is an asymptotic giant branch star of spectral type M6S, with a luminosity class of Ib, indicating a supergiant luminosity. It is around 1,160 light years away.
![]() A visual band light curve for Y Lyncis, adapted from Percy et al. (2001).[1] The top panel shows the brightness variation over a period of several years, and the lower panel shows shorter time scale variations. | |
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Lynx |
Right ascension | 07h 28m 11.61657s[2] |
Declination | +45° 59′ 26.2295″[2] |
Apparent magnitude (V) | 6.2 - 8.9[3] |
Characteristics | |
Spectral type | M6S Ib[4] |
Variable type | SRc[4] |
Astrometry | |
Radial velocity (Rv) | 5.50±0.6[5] km/s |
Proper motion (μ) | RA: −1.278[2] mas/yr Dec.: −4.067[2] mas/yr |
Parallax (π) | 2.8068 ± 0.1138 mas[2] |
Distance | 1,160 ± 50 ly (360 ± 10 pc) |
Details | |
Mass | 1.5 - 2.0[3] M☉ |
Radius | 580[3] R☉ |
Luminosity | 10,765[6] L☉ |
Surface gravity (log g) | 0.0[7] cgs |
Temperature | 3,200[7] K |
Metallicity [Fe/H] | −0.19[7] dex |
Other designations | |
Database references | |
SIMBAD | data |
Y Lyncis ranges in brightness from magnitude 6.2 to 8.9. Its changes in brightness are complex with at least two different periods showing. The General Catalogue of Variable Stars lists a period of 110 days.[8] More recent studies show a primary pulsation period of 133 days, with and a long secondary period with an amplitude of 0.2 magnitudes and duration 1,300 days. The long secondary period variations are possibly caused by long-lived convection cells.[9]
Y Lyncis has a mass around 1.5-2.0 M☉ and a luminosity around 10,000 L☉. It is a thermally pulsing asymptotic giant branch star, an evolved star with a carbon-oxygen core that is fusing helium in a shell and hydrogen in a separate shell.[10] It is also an S-type star, where third dredge-ups have brought some carbon to the surface, but not enough to create a carbon star.[6]