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8 Ursae Minoris, HD133086, HIP73136

8 Ursae Minoris is a orange to red star that can be located in the constellation of UrsaMinor. 8 Ursae Minoris is the brightest star in Ursa Minor based on the Hipparcos 2007 apparent magnitude. The star can not be seen by the naked eye, you need a telescope to see it. It is calculated at being 1.700 Billion Years old. This information comes from ExoPlanet.

HIP73136 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD133086. 8 Ursae Minoris has at least 1 Extrasolar Planets believed to be in orbit around the star.

Location of 8 Ursae Minoris

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 8 Ursae Minoris, the location is 14h 56m 48.32 and +74d54`03.3 .

Proper Motion of 8 Ursae Minoris

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 4.75 ± 0.37 miliarcseconds/year towards the north and 12.82 ± 0.43 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Age, Mass, Radius) of 8 Ursae Minoris

8 Ursae Minoris has a spectral type of K0. This means the star is a orange to red star. The star is 7449.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24295.9074945600000000s. The star has a B-V Colour Index of 0.98 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,016 Kelvin.

8 Ursae Minoris Radius has been calculated as being 7.98 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 5,554,736.32.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 8.51. 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 1.80 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 -0.030000, 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 1.70 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.

8 Ursae Minoris Apparent and Absolute Magnitudes

8 Ursae Minoris has an apparent magnitude of 6.83 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 0.95 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.81. 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 8 Ursae Minoris

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 6.67 which gave the calculated distance to 8 Ursae Minoris as 489.00 light years away from Earth or 149.93 parsecs. It would take a spaceship travelling at the speed of light, 489.00 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 6.25 which put 8 Ursae Minoris at a distance of 521.86 light years or 160 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 7,449.00 Parsecs or 24,295.91 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.

8 Ursae Minoris Facts

Alternative Names

Traditional/Proper Name8 Ursae Minoris
Flamsteed Name8 Ursae Minoris
Flamsteed Short Name8 UMi
Hipparcos Library I.D.73136
Bonner DurchmusterungBD+75 547
Henry Draper Designation133086

Visual Facts

Star Type star
Age1.70 Billion Years Old
Absolute Magnitude0.95 / 0.81
Visual / Apparent Magnitude6.83
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)14h 56m 48.32
Declination (Dec.)+74d54`03.3
Galactic Latitude39.66 degrees
Galactic Longitude112.79 degrees
1997 Distance from Earth6.67 Parallax (milliarcseconds)
 489.00 Light Years
 149.93 Parsecs
2007 Revised Distance from Earth6.25 Parallax (milliarcseconds)
 521.86 Light Years
 160 Parsecs
Galacto-Centric Distance24,295.91 Light Years / 7,449.00 Parsecs
Proper Motion Dec.4.75 ± 0.37 milliarcseconds/year
Proper Motion RA.12.82 ± 0.43 milliarcseconds/year
B-V Index0.98
Radial Velocity-9.95 ± 0.22 km/s
Spectral TypeK0
Colour(K) Orange to Red

Companions (Multi-Star and Exoplanets) Facts

Exoplanet Count1

Estimated Facts

Calculated Effective Temperature5,016 Kelvin
Mass Compared to the Sun1.80

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
133086+75 547.0A7.300007.00000-6.00000K0Orange
+75 549.0B8.80000-48.0000018.000001879

List of Extrasolar Planets orbiting 8 Ursae Minoris

NameStatusMass (Jupiters)Orbital Period (Days)EccentricityDiscoveredSemi-Major AxisPeriastron
8 Umi BConfirmed1.593.4000.0620150.4991.000

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