Hubbry Logo
search
logo
2008342

Lambda Sagittarii

logo
Community Hub0 Subscribers
Write something...
Be the first to start a discussion here.
Be the first to start a discussion here.
See all
Lambda Sagittarii

Lambda Sagittarii (Latinized from λ Sagittarii), formally named Kaus Borealis /ˈkɔːs bɒriˈælɪs/, is a star in the southern constellation of Sagittarius. The star marks the top of the Archer's bow.

With an apparent visual magnitude of +2.81, this is one of the brighter members of the constellation and, according to the Bortle Dark-Sky Scale, it is readily visible to the naked eye. Based upon parallax measurements, it is 78.2 light-years (24.0 parsecs) from the Sun.

Being 2.1 degrees south of the ecliptic, Lambda Sgr is sometimes occulted by the Moon and, rarely, by a planet. The last planet to pass in front of it was Venus, on 19 November 1984. The previous occasion was 5 December 1865, when it was occulted by Mercury.[citation needed]

Kaus Borealis is a giant star with a stellar classification of K1 IIIb. It has a mass 1.8 times that of the Sun and a physical size of about 11.2 times the Sun's radius. This expanded outer envelope is radiating energy at an effective temperature of 4,768 K, causing it to glow with the cool orange hue of a K-type star. It appears to be rotating at a leisurely rate, with a projected rotational velocity of 3.81 km s−1.

On 17 December 2021, it had a close conjunction (geocentric separation <1') with Mercury.

λ Sagittarii (Latinised to Lambda Sagittarii) is the star's Bayer designation.

It bore the traditional name Kaus Borealis, which derives from the Arabic قوس qaws 'bow' and Latin boreālis 'northern'. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Kaus Borealis for this star.

This star, with Gamma Sagittarii, Delta Sagittarii, Epsilon Sagittarii, Zeta Sagittarii, Sigma Sagittarii, Tau Sagittarii and Phi Sagittarii comprises the Teapot asterism.

See all
User Avatar
No comments yet.