Surface temperature 4,860 K Magnitude 3.326 Apparent magnitude (V) 3.326 | Radius 11.14 million km (16 R☉) | |
 | ||
Mass 3.481 × 10^30 kg (1.75 M☉) Similar Sagittarius, Lambda Sagittarii, Zeta Sagittarii, Delta Sagittarii, Omicron Sagittarii | ||
Tau sagittarii scape one solitude of the stars
Tau Sagittarii (Tau Sgr, τ Sagittarii, τ Sgr) is a star in the southern zodiac constellation of Sagittarius.
Contents
Tau sagittarii 12 solitude of the stars
Description
With an apparent visual magnitude of +3.3, this is one of the brighter members of the constellation. The distance of this star from Earth is roughly 122 light-years (37 parsecs), based upon parallax measurements.
This is a spectral type K1 giant star with about 1.25 M☉. The stellar envelope is slightly cooler than the Sun, with an effective temperature of 4,459 giving the star a light orange color. The interferometry-measured angular diameter of this star, after correcting for limb darkening, is 3.93 ± 0.04 mas, which, at its estimated distance, equates to a physical radius of about 16 times the radius of the Sun.
τ Sagittarii is a suspected double star although no companion has been confirmed yet. A lower metal content (Fe to H ratio is 54% lower than the sun's) and a high peculiar velocity (64 km/s, four times the local average) relative to the Sun suggest the star is a visitor from a different part of the Galaxy.
τ Sagittarii is a red clump giant, a star with similar mass to the sun which has exhausted its core hydrogen, passed through the red giant branch, and started helium fusion in its core.
The Wow! signal
τ Sagittarii is the closest visible star in the night sky to the origin of the 1977 Wow! signal.
Name and etymology
