University of Wisconsin

Space Astronomy Laboratory

ASTRO - 2

WUPPE

OBJECT: Sigma Scorpii (SIG-SCO)
Other names: HD 147165
ID # 4541

UW Astronomer: Chris Anderson


Sig-Sco is a visual double star, located about 900 light years away in the constellation of Scorpius, the Scorpion. The primary star is also a member of a spectroscopic binary system (with a close companion), and there is most likely a third companion. The orbital periods of these systems are 34 days and 350 years, respectively. Sig-Sco is a pulsating variable star, showing unpredictable changes and unexpected secondary oscillations. These oscillations may be connected to the tidal effect of the close companion.