AH Scorpii


AH Scorpii is a red supergiant variable star located in the constellation Scorpius. It is one of the largest stars known by radius and is also one of the most luminous red supergiant stars in the Milky Way.

Distance

The distance of AH Scorpii is considered to be uncertain. VLBI measurements of the masers have provided an accurate distance of 2,260 parsecs based on observation of SiO, H2O, and OH masers in its oxygen-rich circumstellar material. The masers were observed to be approaching the star at 13 km/s, indicating overall contraction at around phase 0.55 of the visual variations. AH Scorpii has a parallax of in Gaia Data Release 2, but that value is considered unreliable due to a very high level of astrometric noise. Parallax values from the Hipparcos mission are negative and have relatively large statistical margins of error.

Characteristics

AH Scorpii is a dust-enshrouded red supergiant and is classified as a semiregular variable star with a main period of 714 days. The total visual magnitude range is 6.5 - 9.6. No long secondary periods have been detected. Modelling of AH Scorpii near maximum light has determined an effective temperature of and a luminosity of. A radius of was determined from an angular diameter of and the given distance of.