|Designation|| θ Scorpii|
|Right ascension||17h 37m 19.1299s|
|Declination||-42° 59′ 52.1808″|
|Type of object||Giant star|
|Magnitude|| Apparent Mag: +1.86|
Absolute Mag: -2.96
|Distance from Earth||300.33 ly|
|Radial velocity||1.4±2 km/s|
|Proper motion|| RA: 5.54 mas/yr|
Dec.: -3.12 mas/yr
|Parallax||10.86±1.49 mas mas|
Theta Scorpii, also known as Sargas, is a giant star in the constellation of Scorpius, the scorpion. Its traditional name of Sargas is of Sumerian origin but its meaning in Sumerian is not known. It's also sometimes called "Girtab" which is also Sumerian and is known to mean "scorpion". However this is normally used to refer to another star in Scorpius, namely Kappa Scorpii. The star is yellow belonging to the spectral class F0II. It also has a fainter companion star with a magnitude of +5.36, located 6.470 arc seconds from Theta Scropii. Theta Scorpii's low declination of -43° means it is normally observed close to the horizon in the Northern hemisphere. This is useful for testing how the brightness of a star changes when it is seen close to the horizon, where its light must travel though a lot of atmosphere.
The star is thought to lie 300.33 light years from Earth, though other sources place it lower at 272 ly. Sargas weighs 5.7 solar masses and has a radius of 26 solar radii. Its surface is hotter than that of the Sun at an estimated 7,200 kelvin and it radiates 1,834 times as much energy than the Sun. Its equatorial rotation speed is over 50 times that of the Sun, but the large size still gives it a fairly long rotation period of 10 days.
- Theta Scorpii. Simbad Astronomical Database. simbad.u-strasbg.fr. Retrieved on 2019-07-21.
- van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics 474 (2): 653-664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. arXiv:0708.1752
- Sargas (Theta Scorpii). universeguide.com. Retrieved on 2019-07-21.
- Wilson, R. (1953). General catalogue of stellar radial velocities. Carnegie Institute Washington D.C. Publication. Bibcode:1953GCRV..C......0W
- Scorpius Constellation. constellation-guide.com. Retrieved on 2019-07-21.
- Jim Kaler (2015-06-16). Girtab. Stars. stars.astro.illinois.edu. Retrieved on 2019-07-21.