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Alula Borealis, Nu Ursae Majoris, 54 Ursae Majoris, HD98262, HIP55219, HR4377

Alula Borealis (Nu Ursae Majoris) is a orange to red giant star that can be located in the constellation of UrsaMajor. Alula Borealis is the brightest star in Ursa Major based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it. It is calculated at being 4.604 Billion Years old. This information comes from ExoPlanet.

Nu Ursae Majoris is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR4377. HIP55219 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD98262.

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Location of Alula Borealis

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 Alula Borealis, the location is 11h 18m 28.76 and +33d05`39.3 .

Proper Motion of Alula Borealis

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 28.69 ± 0.12 miliarcseconds/year towards the north and -26.84 ± 0.17 miliarcseconds/year east if we saw them in the horizon.

Alula Borealis Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 58.0000000 that I have given is based on the Spectral Types page that I have found on the Internet. You might find a different figure, one that may have been calculated rather than generalised that I have done. The figure is always the amount times the luminosity of the Sun. It is an imprecise figure because of a number of factors including but not limited to whether the star is a variable star and distance.

Physical Properties (Colour, Temperature, Age, Mass, Radius) of Alula Borealis

Alula Borealis has a spectral type of K3III SB. This means the star is a orange to red giant star. The star is 7444.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24279.5993273600000000s. The star has a B-V Colour Index of 1.4 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,159 Kelvin.

Alula Borealis Radius has been calculated as being 46.66 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 32,466,114.19.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 44.15. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's solar mass is 1.23 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 -0.250000, 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 4.60 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.

Alula Borealis Apparent and Absolute Magnitudes

Alula Borealis has an apparent magnitude of 3.49 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 -2.07 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.95. 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 Alula Borealis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 7.74 which gave the calculated distance to Alula Borealis as 421.40 light years away from Earth or 129.20 parsecs. It would take a spaceship travelling at the speed of light, 421.40 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 8.17 which put Alula Borealis at a distance of 399.22 light years or 122.40 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.

The star's Galacto-Centric Distance is 7,444.00 Parsecs or 24,279.60 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

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 Metallicity and/or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

Alula Borealis Facts

Alternative Names

Traditional/Proper NameAlula Borealis
Flamsteed Name54 Ursae Majoris
Flamsteed Short Name54 UMa
Bayer DesignationNu Ursae Majoris
Hipparcos Library I.D.55219
Yale Bright Star Catalogue (HR) Id4377
Bonner DurchmusterungBD+33 2098
Henry Draper Designation98262

Visual Facts

Star Typegiant star
Age4.60 Billion Years Old
Absolute Magnitude-2.07 / -1.95
Visual / Apparent Magnitude3.49
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)11h 18m 28.76
Declination (Dec.)+33d05`39.3
Galactic Latitude69.08 degrees
Galactic Longitude190.73 degrees
1997 Distance from Earth7.74 Parallax (milliarcseconds)
 421.40 Light Years
 129.20 Parsecs
2007 Revised Distance from Earth8.17 Parallax (milliarcseconds)
 399.22 Light Years
 122.40 Parsecs
Galacto-Centric Distance24,279.60 Light Years / 7,444.00 Parsecs
Proper Motion Dec.28.69 ± 0.12 milliarcseconds/year
Proper Motion RA.-26.84 ± 0.17 milliarcseconds/year
B-V Index1.40
Radial Velocity-9.63 ± 0.38 km/s
Iron Abundance-0.11 ± 9.99 Fe/H
Spectral TypeK3III SB
Colour(K) Orange to Red

Estimated Facts

Luminosity (x the Sun)58.0000000
Calculated Effective Temperature4,159 Kelvin
Mass Compared to the Sun1.23
Metallicity-0.25000

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
98262+33 2098.0A3.70000-27.0000023.00000K0Orange
B10.10000-28.0000019.000001830

Location of Alula Borealis in Ursa Major


Alula Borealis (Nu Ursae Majoris) Location in Ursa Major

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


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