Kaus Borealis / Lambda Sagittarii Star Facts (Type, Distance, Magnitude, Age, Colour, Location and more)

Kaus Borealis, also known as Lambda Sagittarii (Bayer) is a giant star located in the constellation of Sagittarius, Half-Man/Half-Horse Archer. Kaus Borealis is a major star and forms part of the constellation.

Based on the spectral type (K1IIIb), Kaus Borealis colour is orange to red, these are stars that are cooler than our own star.


Kaus Borealis temperature is in the range of between 3,700 and 5,200 Kelvin. Kaus Borealis effective temperature is 4,732 Kelvin which is cooler than the Sun's effective temperature which is 5,777 Kelvin. Based on a parallax of 41.72, Kaus Borealis distance from Earth can be calculated at being 78.18 light years away or 23.70 parsecs.

Kaus Borealis is a naked-eye star, so you don't need a telescope or binoculars when you look up on a clear night. The lower the magnitude, the easier it will be to see it.

Location

The location of the Kaus Borealis in the night sky is determined by the right ascension (R.A.) and declination (Dec.). These are equivalent to the Longitude and Latitude on Earth. The Right Ascension (Longitude) is expressed in time (hh:mm:ss) and is how far the star is along Earth's celestial equator. If the R.A. is positive, then it's eastwards and vice versa.

The Declination (Latitude) is how far north or south the object is compared to the celestial equator and is expressed in degrees. If the value is positive, it is north of the celestial equator. For Kaus Borealis, the location is 18h 27m 58.27 and -25° 25` 16.5 .

Based on the location of Sagittarius, Kaus Borealis can be located in the southern hemisphere of the celestial sky. The celestial hemisphere is equivalent to the hemispheres on Earth. Kaus Borealis is on the Ecliptic. The Ecliptic is the path that the Earth takes as it orbits the Sun. As the Earth is titled, we therefore have Celestial and Ecliptic hemispheres and they can be different for a star.

Physical Properties

Spectral Type

Kaus Borealis spectral type of K1IIIb which means its colour and type is orange to red giant star. There is no relationship between colour and size. For example, a red star can be large or small. Small stars are more energy efficient than larger stars and live longer.

Kaus Borealis Luminosity

Luminosity is the amount of energy a star pumps out relative to the amount that our star, the Sun, gives out. Our star, the Sun's value is 1. Kaus Borealis Luminosity figure of 53.03 comes from the Vizier online catalogue. The star generates more energy than our star.

Iron Abundance

Kaus Borealis Iron Abundance is -0.07 with an error value of 0.03 Fe/H, with the Sun having a value of 1 to put it into context. The value comes from the Hipparcos Extended Catalog.

Magnitude (Apparent / Absolute / Visible)

A number represents a star’s magnitude, whether apparent/visual or absolute. The smaller the number, the brighter the star is. The Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Kaus Borealis apparent magnitude is 2.82, which is a measure of the star's brightness as seen from Earth. Apparent Magnitude is also known as Visual Magnitude.

If you use the 1997 parallax value, Kaus Borealis' absolute magnitude is 0.95. If you use the 2007 parallax value, Kaus Borealis' absolute magnitude is 0.92. Absolute Magnitude is the star's apparent magnitude from 10 parsecs or 32.6 light years. The magnitude assumes nothing is between the object and the viewer, such as dust clouds. To compare different stars' actual brightness, you would best use Absolute rather than Apparent Magnitude.

Kaus Borealis is visible from Earth without needing binoculars or a telescope. The lower the Apparent Magnitude of a star or other object is, the easier it is to see in the night sky. An object with a magnitude greater than 6.5 cannot be seen without a telescope or other device.


Radial Velocity and Proper Motion

In simplistic terms, all non-rogue stars, like planets, orbit around a central object, although that is actually not true. Where is the centre of the Solar System. For simplicity it's the central star, such as the Sun. In the case of a star, it's the galactic centre. The constellations we see today will be different than they were 50,000 years ago or 50,000 years from now.

Proper motion details the movements of these stars and is measured in milliarcseconds. Kaus Borealis is moving -185.66 ± 0.09 milliarcseconds/year towards the north and -44.76 ± 0.16 milliarcseconds/year east if we saw them in the horizon.

The radial velocity, the speed at which the Kaus Borealis is towards the Sun, is -43.20000 km/s with an error of about 0.80 km/s . When the value is negative, the star and the Sun are getting closer to one another; likewise, a positive number means that two stars are moving away. It's nothing to fear as the stars are so far apart they won't collide in our lifetime, if ever.

Kaus Borealis Fact Table

The table is scrollable if you can't see everything, just swipe the table to see the hidden information.

Primary NameKaus Borealis
Spectral TypeK1IIIb
Star TypeHigh proper-motion Star
Colour orange to red
GalaxyMilky Way
ConstellationSagittarius
Main StarYes
Absolute Magnitude 0.95 / 0.92
Visual / Apparent Magnitude2.82
Visible From Earth Yes
Right Ascension (R.A.)18h 27m 58.27
Declination (Dec.)-25° 25` 16.5
Galactic Latitude-6.52165704 °
Galactic Longitude7.66074200 °
1997 Distance from Earth42.20000 Parallax (milliarcseconds)
 77.29 Light Years
 23.70 Parsecs
2007 Distance from Earth41.72000 Parallax (milliarcseconds)
 78.18 Light Years
 23.97 Parsecs
 4,944,132.955 Astronomical Units
Galacto-Centric Distance24,057.808 Light Years / 7,376 Parsecs
Proper Motion Dec.-185.66000 ± 0.09000 milliarcseconds/year
Proper Motion RA.-44.76000 ± 0.16000 milliarcseconds/year
B-V Index1.02
Radial Velocity-43.20000 ± 0.8 km/s
Iron Abundance (Fe/H)-0.0700 ± 0.03
Eccentricity0.16500
Semi-Major Axis6617.0000000
Luminosity (Lsun)53.0300000
Effective Temp. (Kelvin) 4,732

Sources and Links


Modified Date13th July 2024
Published DateJan 2015
SIMBAD SourceLink
EPIC SourceEpic Search
SourceVizier,


Comments and Questions

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shane jamieson

kaus borealis is the centre of the golden pyrimid of TICA IN SOUTH AMERICA.