Zeta2 Lyrae is a single,[10] white-hued star in the northern constellation of Lyra. It is a dim star that is just visible to the naked eye with an apparent visual magnitude of 5.74[2] An annual parallax shift of 20.6 mas as seen from Earth provides a distance estimate of about 158 light years from the Sun. It is moving closer to the Sun with a radial velocity of −25 km/s.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 18h 44m 48.19919s[1] |
| Declination | +37° 35′ 40.5585″[1] |
| Apparent magnitude (V) | 5.74[2] |
| Characteristics | |
| Spectral type | F0 IVn[3] or F1Vnn[4] |
| U−B color index | +0.06[2] |
| B−V color index | +0.29[2] |
| Astrometry | |
| Radial velocity (Rv) | −25.0±3.7[5] km/s |
| Proper motion (μ) | RA: +23.969[1] mas/yr Dec.: +23.461[1] mas/yr |
| Parallax (π) | 20.6386 ± 0.0443 mas[1] |
| Distance | 158.0 ± 0.3 ly (48.5 ± 0.1 pc) |
| Absolute magnitude (MV) | +2.34[6] |
| Details | |
| Mass | 1.74[7] M☉ |
| Radius | 2.03±0.02[1] R☉ |
| Luminosity | 9.5±0.1[1] L☉ |
| Surface gravity (log g) | 3.94[7] cgs |
| Temperature | 7,257+37 −3[1] K |
| Metallicity [Fe/H] | −0.36[1] dex |
| Rotational velocity (v sin i) | 212[8] km/s |
| Age | 1.223[7] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This star has a stellar classification of F0 IVn,[3] suggesting it is an F-type subgiant star that is evolving away from the main sequence as its supply of hydrogen at the core has been consumed. The n suffix indicates "nebulous" lines caused by its rotation. It is spinning rapidly with a projected rotational velocity of 212 km/s.[8] This is giving the star an oblate shape with an equatorial bulge that is an estimated 29% larger than the polar radius.[11] The star is radiating approximately 9.6 times the Sun's luminosity from the photosphere at an effective temperature of about 7,000 K.[1] It has 1.7[7] times the mass of the Sun, twice the Sun's radius,[1] and is about 1.2[7] billion years old.
It is a suspected variable.[9]
References
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