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Kochab (Beta Ursae Minoris) - HD131873 - HIP72607 - HR5563

Kochab (Beta Ursae Minoris) is a orange to red giant star that can be located in the constellation of UrsaMinor. It is the 58th brightest star in the night sky. It is calculated at being 3.000 Billion Years old. This information comes from ExoPlanet. Beta Ursae Minoris is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR5563. HIP72607 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD131873. Kochab has alternative name(s), 7 Ursae Minoris , 7 UMi.

Location of Kochab

The location of the star in the galaxy is determined by the Right Ascension (R.A.) and Declination (Dec.), these are equivalent to the Longitude and Latitude on the Earth. The Right Ascension is how far expressed in time (hh:mm:ss) the star is along the celestial equator. If the R.A. is positive then its eastwards. The Declination is how far north or south the star is compared to the celestial equator and is expressed in degrees. For Kochab, the location is 14h 50m 42.40 and +74d09`19.7 .

Proper Motion of Kochab

All stars like planets orbit round a central spot, in the case of planets, its the central star such as the Sun. In the case of a star, its the galactic centre. The constellations that 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 are measured in milliarcseconds. The star is moving 011.42 ± 000.11 towards the north and -032.61 ± 000.12 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Age, Mass, Radius) of Kochab

Kochab has a spectral type of K4IIIvar. This means the star is a orange to red giant star. The star has a B-V Colour Index of 1.46 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,059 Kelvin.

Kochab has been calculated as 28.19 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 19,613,643.12.km. The star's solar mass is 1.00 times that of the Sun's. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

The star's metallicity is -0.270000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.

The star is believed to be about 3.00 Billion years old. To put in context, the Sun is believed to be about five billion years old and the Universe is about 13.8 billion years old.

Kochab Apparent and Absolute Magnitudes

Kochab has an apparent magnitude of 2.07 which is how bright we see the star from Earth. Apparent Magnitude is also known as Visual Magnitude. If you used the 1997 Parallax value, you would get an absolute magnitude of -0.87 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.95. Magnitude, whether it be apparent/visual or absolute magnitude is measured by a number, the smaller the number, the brighter the Star is. Our own Sun is the brightest star and therefore has the lowest of all magnitudes, -26.74. A faint star will have a high number.

Distance to Kochab

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 25.79 which gave the calculated distance to Kochab as 126.47 light years away from Earth or 38.77 parsecs. It would take a spaceship travelling at the speed of light, 126.47 years to get there. We don't have the technology or spaceship that can carry people over that distance yet.

In 2007, Hipparcos data was revised with a new parallax of 24.91 which put Kochab at a distance of 130.94 light years or 40.14 parsecs. It should not be taken as though the star is moving closer or further away from us. It is purely that the distance was recalculated.

Meteor Showers Radiating from near Kochab

The Ursids Meteor Shower radiants from a point near this star. The meteor shower runs typically between December 17-25 with a peak date of Dec. 22. The speed of a meteor in the shower is 33 Km/s. The amount of meteors predicted to be seen per hour (Zenith Hourly Rate) is 33.

Source of Information

The source of the information if it has a Hip I.D. is from Simbad, the Hipparcos data library based at the University at Strasbourg, France. Hipparcos was a E.S.A. satellite operation launched in 1989 for four years. The items in red are values that I've calculated so they could well be wrong. Information regarding Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

Kochab Facts

Alternative Names

Traditional NameKochab
Short Name7 UMi
Bayer DesignationBeta Ursae Minoris
Alternative Name(s)7 Ursae Minoris
Hipparcos Library I.D.72607
Yale Bright Star Catalogue (HR) Id5563
Bonner DurchmusterungBD+74 595
Henry Draper Designation131873

Visual Facts

Star Typegiant star
Age3.000 Billions of Years
Absolute Magnitude-0.87 / -0.95
Apparent Magnitude2.07
Right Ascension (R.A.)14h 50m 42.40
Declination (Dec.)+74d09`19.7
1997 Distance from Earth25.79 Parallax (milliarcseconds)
 126.47 Light Years
 38.77 Parsecs
2007 Revised Distance from Earth24.91 Parallax (milliarcseconds)
 130.94 Light Years
 40.14 Parsecs
Proper Motion Dec.11.42 ± 0.11 milliarcseconds/year
Proper Motion RA.-32.61 ± 0.12 milliarcseconds/year
B-V Index1.46
Spectral TypeK4IIIvar
Brightest in Night Sky58th
Colour(K) Orange to Red

Estimated Facts

Radius (x the Sun)28.19
Calculated Effective Temperature4,059 Kelvin
Mass Compared to the Sun1.00
Metallicity-0.27000

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.


Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
131873+74 595.0A2.20000-34.0000010.00000K5Orange
B11.400001908

Location of Kochab in Ursa Minor


Kochab (Beta Ursae Minoris) Location in Ursa Minor

The map was generated using Night Vision, an awesome free application by Brian Simpson.

Kochab Solar System


This is a N.A.S.A. impression of what the solar system might look like. If the star is not on display, its because its so small compared to the orbits of the outer planets. The green area denotes the habital zone which if the planet is within that area, life could exist. The habital zone might not appear on the picture because its outside the area for the picture. Our planets show the orbit of the planet if its was in our solar system. For more information about the planet and other exoplanetary stuff, visit N.A.S.A.

Kochab Solar System

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