Upsilon Scorpii
Upsilon Scorpii (υ Scorpii, abbreviated Upsilon Sco, υ Sco), formally named Lesath /ˈliːsæθ/, is a star located in the "stinger" of the southern zodiac constellation of Scorpius, the scorpion. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 580 light-years from the Sun. In the night sky it lies near the 1.6 magnitude star Lambda Scorpii, and the two form an optical pair that is sometimes called the "Cat's Eyes".
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h 30m 45.83712s |
| Declination | –37° 17′ 44.9285″ |
| Apparent magnitude (V) | 2.70 |
| Characteristics | |
| Spectral type | B2 IV |
| U−B color index | –0.854 |
| B−V color index | –0.221 |
| Astrometry | |
| Radial velocity (Rv) | +8.0 km/s |
| Proper motion (μ) | RA: –2.37 mas/yr Dec.: 30.09 mas/yr |
| Parallax (π) | 5.66 ± 0.18 mas |
| Distance | 580 ± 20 ly (177 ± 6 pc) |
| Absolute magnitude (MV) | −3.53 |
| Details | |
| Mass | 11.4 ± 0.5 M☉ |
| Radius | 6.1 R☉ |
| Luminosity | 7381 L☉ |
| Temperature | 22,831 ± 169 K |
| Age | 20.0 ± 2.6 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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