Epsilon Lyrae
Epsilon Lyrae (ε Lyr, ε Lyrae), also known as the Double Double, is a multiple star system of at least five stars approximately 162 light-years away in the constellation of Lyra.
ε (circled) in the constellation Lyra. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Lyra |
| Epsilon1 Lyrae | |
| Right ascension | 18h 44m 20.34589s |
| Declination | +39° 40′ 12.4533″ |
| Apparent magnitude (V) | 4.66 |
| Epsilon2 Lyrae | |
| Right ascension | 18h 44m 22.78056s |
| Declination | +39° 36′ 45.7851″ |
| Apparent magnitude (V) | 4.59 |
| Characteristics | |
| ε1 Lyr | |
| Spectral type | A3V + F0V |
| U−B color index | +0.065 |
| B−V color index | +0.16 |
| ε2 Lyr | |
| Spectral type | A6Vn + A7Vn |
| U−B color index | +0.075 |
| B−V color index | +0.18 |
| Astrometry | |
| ε1 Lyr | |
| Radial velocity (Rv) | −31.20 ± 1.7 km/s |
| Proper motion (μ) | RA: 11.09 mas/yr Dec.: 61.39 mas/yr |
| Parallax (π) | 20.10 ± 0.76 mas |
| Distance | 162 ± 6 ly (50 ± 2 pc) |
| Absolute magnitude (MV) | 1.2 |
| ε2 Lyr | |
| Radial velocity (Rv) | −24.40 ± 1.7 km/s |
| Proper motion (μ) | RA: 6.18 mas/yr Dec.: 50.42 mas/yr |
| Parallax (π) | 20.97 ± 0.50 mas |
| Distance | 156 ± 4 ly (48 ± 1 pc) |
| Absolute magnitude (MV) | 1.2 |
| Details | |
| ε1 Lyr A | |
| Mass | 2.03 M☉ |
| Luminosity | 24 L☉ |
| Temperature | 7,943 K |
| Rotational velocity (v sin i) | 165 km/s |
| ε1 Lyr B | |
| Mass | 1.61 M☉ |
| Luminosity | 8.4 L☉ |
| Temperature | 7,047 K |
| Rotational velocity (v sin i) | 159 km/s |
| ε2 Lyr A | |
| Mass | 2.11 M☉ |
| Luminosity | 29 L☉ |
| Temperature | 7,816 K |
| Rotational velocity (v sin i) | 212 km/s |
| ε2 Lyr B | |
| Mass | 2.15 M☉ |
| Luminosity | 32 L☉ |
| Temperature | 7,852 K |
| Rotational velocity (v sin i) | 233 km/s |
| Other designations | |
| ε1 Lyr: 4 Lyrae, HIP 91919, BD+39°3509 | |
| ε1 Lyr A: HD 173582, HR 7051, SAO 67310 | |
| ε1 Lyr B: HD 173583, HR 7052, SAO 67309 | |
| Other designations | |
| ε2 Lyr: 5 Lyrae, HIP 91926, BD+39°3510 | |
| ε2 Lyr A: HD 173607, HR 7053, SAO 67315 | |
| ε2 Lyr B: HD 173608, HR 7054 | |
| Database references | |
| ε1 Lyr | |
| ε1 Lyr A | |
| ε1 Lyr B | |
| ε2 Lyr | |
| ε2 Lyr A | |
| ε2 Lyr B | |
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