Y Lyncis
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). 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 |
| Declination | +45° 59′ 26.2295″ |
| Apparent magnitude (V) | 6.2 - 8.9 |
| Characteristics | |
| Spectral type | M6S Ib |
| Variable type | SRc |
| Astrometry | |
| Radial velocity (Rv) | 5.50±0.6 km/s |
| Proper motion (μ) | RA: −1.278 mas/yr Dec.: −4.067 mas/yr |
| Parallax (π) | 2.8068 ± 0.1138 mas |
| Distance | 1,160 ± 50 ly (360 ± 10 pc) |
| Details | |
| Mass | 1.5 - 2.0 M☉ |
| Radius | 580 R☉ |
| Luminosity | 10,765 L☉ |
| Surface gravity (log g) | 0.0 cgs |
| Temperature | 3,200 K |
| Metallicity [Fe/H] | −0.19 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. 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.
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. 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.