Lambda Sagittarii

λ Sagittarii

Location of λ Sagittarii (circled)
Observation data J2000.0
Constellation	Sagittarius
Right ascension	18h 27m 58.24072s[1]
Declination	−25° 25′ 18.1146″[1]
Apparent magnitude (V)	+2.82[2]
Characteristics
Spectral type	K0 IV[3]
U−B color index	+0.903[4]
B−V color index	+1.045[4]
Distance		78.2 ± 0.3 ly (23.97 ± 0.09 pc)
Absolute magnitude (MV)	1.07±0.008[5]
Details Rotational velocity (v sin i)		3.81 km/s
PPM  268438
Database references
SIMBAD	data

Lambda Sagittarii (Latinized from λ Sagittarii), formally named Kaus Borealis /ˈkɔːs bɒriˈælɪs/,^[8][9] is a star in the southern constellation of Sagittarius. The star marks the top of the Archer's bow.

Properties

With an

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

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)^[12] to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016^[13] 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.^[14]

In the catalogue of stars in the Calendarium of Al Achsasi al Mouakket, this star was designated Rai al Naaim, which was translated into Latin as Pastor Struthionum, meaning keeper of the ostriches.^[15]

This star is Al Tizini's Rāʽi al Naʽāïm (ألراع ٱلنعم), the Keeper of the Naʽams (Ostrich), meaning the "keeper" the two asterisms al-Naʽām al-Wārid ( النعام الوارد ), "The Going Ostriches" and al-Naʽām al-Ṣādir (النعم الصادر), "The Returning Ostriches".^[16]

In Chinese, 斗 (Dǒu), meaning Dipper, refers to an asterism consisting of Lambda Sagittarii, Phi Sagittarii, Mu Sagittarii, Sigma Sagittarii, Tau Sagittarii and Zeta Sagittarii. Consequently, Lambda Sagittarii itself is 斗宿二 (Dǒu Sù èr, English: the Second Star of Dipper.)^[17]

References