Upsilon Scorpii

υ Scorpii

Location of υ Scorpii (circled)
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 ± 0.18mas
Distance	580 ± 20 ly (177 ± 6 pc)
Details
Mass	11.4 ± 0.5 M☉
Radius	6.1 R☉
Temperature	22,831 ± 169 K
Age	20.0 ± 2.6 Myr
Other designations
υ Sco, 34 Sco, 34 Scorpii, CD-37° 11638, HD 158408, HIP 85696, HR 6508, SAO 208896.
Database references
SIMBAD	data

Upsilon Scorpii (υ Scorpii, abbreviated Upsilon Sco, υ Sco), also named Lesath, is a star located in the "stinger" of the southern zodiac constellation of Scorpius, the scorpion. On 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".

υ Scorpii (Latinised to Upsilon Scorpii) is the star's Bayer designation.

It bore the traditional name Lesath (alternatively spelled Leschath, Lesuth), from the Arabic las'a "pass (or bite) of a poisonous animal"; but this is a miscorrection by Scaliger (a European astronomer who knew Arabic) for earlier "Alascha", which came from Arabic al laţkha "the foggy patch", referring to the nearby open cluster M7. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalogue and standardize proper names for stars. The WGSN approved the name Lesath for this star on 21 August 2016 and it is now so entered in the IAU Catalog of Star Names.

Together with Lambda Scorpii (Shaula), Lesath is listed in the Babylonian compendium MUL.APIN as ^dSharur₄ u ^dShargaz, meaning "Sharur and Shargaz". In Coptic, they were called Minamref The indigenous Boorong people of northwestern Victoria named it as Karik Karik (together with Lambda Scorpii), "the Falcons"