Epoch J2000.0 Equinox J2000.0
|Right ascension||17h 30m 45.83712s|
|Declination||–37° 17′ 44.9285″|
|Apparent magnitude (V)||2.70|
|Spectral type||B2 IV|
|U−B color index||–0.854|
|B−V color index||–0.221|
|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)
|Mass||11.4 ± 0.5 M☉|
|Temperature||22,831 ± 169 K|
|Age||20.0 ± 2.6 Myr|
Upsilon Scorpii (υ Sco, υ Scorpii) is a star located in the "stinger" of the southern zodiac constellation of Scorpius, the scorpion. It has the traditional name Lesath (alternative spellings Leschath, Lesuth), from 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. On the night sky it lies near the 1.6 magnitude star Lambda Scorpii, so the two form an optical pair that is sometimes called the "Cat's Eyes".
This star has apparent magnitude +2.7 and belongs to spectral class B2 IV, with the luminosity class of 'IV' indicating it is a subgiant star. From parallax measurements, it is approximately 580 light years from Earth. The star's luminosity is 12,300 times that of the Sun, while its surface temperature is 22,831 kelvins. The star has a radius of 6.1 times solar and 11 times the mass of the Sun.
- Together with λ Sco (Shaula), Lesath is listed in 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 λ Sco), "the Falcons"
- USS Lesuth (AK-125) was a United States Navy Crater class cargo ship named after the star.
- van Leeuwen, F. (November 2007), Validation of the new Hipparcos reduction, Astronomy and Astrophysics 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357
- Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), A photometric investigation of the Scorpio-Centaurus association, Astrophysical Journal Supplement 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168
- Houk, Nancy; Smith-Moore, M. (1979), Michigan catalogue of two-dimensional spectral types for the HD stars 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1982mcts.book.....H
- Wielen, R. et al. (1999), Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions (35), Astronomisches Rechen-Institut Heidelberg, Bibcode:1999VeARI..35....1W
- Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun, Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x
- Underhill, A. B. et al. (November 1979), Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars, Monthly Notices of the Royal Astronomical Society 189: 601–605, Bibcode:1979MNRAS.189..601U
- ups Sco -- Star, SIMBAD (Centre de Données astronomiques de Strasbourg), retrieved 2012-01-01
- Schaaf, Fred (2007), The 50 best sights in astronomy and how to see them: observing eclipses, bright comets, meteor showers, and other celestial wonders, John Wiley and Sons, p. 95, ISBN 0-471-69657-9
- Kaler, James B., LESATH (Upsilon Scorpii), Stars (University of Illinois), retrieved 2012-01-28
- Rogers, J. H. (February 1998), Origins of the ancient constellations: I. The Mesopotamian traditions, Journal of the British Astronomical Association 108 (1): 9–28, Bibcode:1998JBAA..108....9R
- p. 1678, Burnham's Celestial Handbook: An Observer's Guide to the Universe Beyond the Solar System, Volume 3, Robert Burnham, New York, Dover Publication, Inc, 1978.
- Hamacher, Duane W.; Frew, David J. (2010). "An Aboriginal Australian Record of the Great Eruption of Eta Carinae". Journal of Astronomical History & Heritage 13 (3): 220–34.
- Stanbridge, WM (1857). "On the Astronomy and Mythology of the Aboriginies of Victoria". Transactions Philosophical Institute Victoria 2: 137–140.