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40 Ursae Majoris, HD93075, HIP52650

40 Ursae Majoris is a blue main sequence dwarf star that can be located in the constellation of UrsaMajor. The star can not be seen by the naked eye, you need a telescope to see it.

HIP52650 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD93075.

Location of 40 Ursae Majoris

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 40 Ursae Majoris, the location is 10h 45m 59.86 and +56d55`14.9 .

Proper Motion of 40 Ursae Majoris

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 16.56 ± 0.34 miliarcseconds/year towards the north and 12.14 ± 0.53 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 40 Ursae Majoris

40 Ursae Majoris has a spectral type of A8V. This means the star is a blue main sequence dwarf star. The star is 7460.00000000 Parsecs from the Galactic Centre or terms of Light Years is 24331.7854624000000000s. The star has a B-V Colour Index of 0.31 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 7,167 Kelvin.

40 Ursae Majoris Radius has been calculated as being 2.55 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,772,942.15.km. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 2.60. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

40 Ursae Majoris Apparent and Absolute Magnitudes

40 Ursae Majoris has an apparent magnitude of 7.11 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 1.88 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.84. 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 40 Ursae Majoris

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 8.99 which gave the calculated distance to 40 Ursae Majoris as 362.81 light years away from Earth or 111.23 parsecs. It would take a spaceship travelling at the speed of light, 362.81 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 8.83 which put 40 Ursae Majoris at a distance of 369.38 light years or 113.25 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 7,460.00 Parsecs or 24,331.79 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.

40 Ursae Majoris Facts

Alternative Names

Traditional/Proper Name40 Ursae Majoris
Flamsteed Name40 Ursae Majoris
Flamsteed Short Name40 UMa
Hipparcos Library I.D.52650
Bonner DurchmusterungBD+57 1290
Henry Draper Designation93075

Visual Facts

Star Typemain sequence dwarf star
Absolute Magnitude1.88 / 1.84
Visual / Apparent Magnitude7.11
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)10h 45m 59.86
Declination (Dec.)+56d55`14.9
Galactic Latitude52.83 degrees
Galactic Longitude150.98 degrees
1997 Distance from Earth8.99 Parallax (milliarcseconds)
 362.81 Light Years
 111.23 Parsecs
2007 Revised Distance from Earth8.83 Parallax (milliarcseconds)
 369.38 Light Years
 113.25 Parsecs
Galacto-Centric Distance24,331.79 Light Years / 7,460.00 Parsecs
Proper Motion Dec.16.56 ± 0.34 milliarcseconds/year
Proper Motion RA.12.14 ± 0.53 milliarcseconds/year
B-V Index0.31
Radial Velocity-19.30 ± 7.40 km/s
Spectral TypeA8V
Colour(A) blue

Estimated Facts

Calculated Effective Temperature7,167 Kelvin

Sources and Links

SIMBAD SourceLink

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