Universe Guide

17 Ursae Minoris

17 Ursae Minoris Facts

  • 17 Ursae Minoris is a star that can be located in the constellation of Ursa Minor. The description is based on the spectral class.
  • 17 Ursae Minoris is not part of the constellation outline but is within the borders of the constellation.
  • Based on the spectral type (G5) of the star, the star's colour is yellow .
  • The star can not be seen by the naked eye, you need a telescope to see it.
  • Using the most recent figures given by the 2007 Hipparcos data, the star is 627.24 light years away from us. Distance

17 Ursae Minoris's Alternative Names

HIP77942 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD143803.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John named the stars in the constellation with a number and its latin name, this star's Flamsteed designation is 17 Ursae Minoris. The Flamsteed name can be shortened to 17 UMi.

BD number is the number that the star was filed under in the Durchmusterung or Bonner Durchmusterung, a star catalogue that was put together by the Bonn Observatory between 1859 to 1903. The star's BD Number is BD+75 579.

More details on objects' alternative names can be found at Star Names .

Location of 17 Ursae Minoris

The location of the star in the night sky 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 object is compared to the celestial equator and is expressed in degrees. For 17 Ursae Minoris, the location is 15h 55m 01.06 and +75° 34` 27.5 .

Radial Velocity and Proper Motion of 17 Ursae Minoris

Proper Motion

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 -9.59 ± 0.36 milliarcseconds/year towards the north and 17.45 ± 0.38 milliarcseconds/year east if we saw them in the horizon.

Radial Velocity

The Radial Velocity, that is the speed at which the star is moving away/towards the Sun is -18.90000 km/s with an error of about 3.00 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

Physical Properties of 17 Ursae Minoris

17 Ursae Minoris Colour and Temperature

Based on the star's spectral type of G5 , 17 Ursae Minoris's colour and type is yellow star. The star has a B-V Colour Index of 0.83 which means the star's temperature is about 5,353 Kelvin. The temperature was calculated using information from Morgans @ Uni.edu.

17 Ursae Minoris 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 67.99 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

17 Ursae Minoris Radius

17 Ursae Minoris estimated radius has been calculated as being 10.71 times bigger than the Sun. The Sun's radius is 695,800km, therefore the star's radius is an estimated 7,450,630.89.km. If you need the diameter of the star, you just need to multiple the radius by 2. However with the 2007 release of updated Hipparcos files, the radius is now calculated at being round 8.784244248832262591800903415. The figure is derived at by using the formula from SDSS rather than peer reviewed papers. It has been known to produce widely incorrect figures.

17 Ursae Minoris Apparent and Absolute Magnitudes

17 Ursae Minoris has an apparent magnitude of 6.88 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 0.03 If you used the 2007 Parallax value, you would get an absolute magnitude of 0.46. 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 17 Ursae Minoris

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 4.26000 which gave the calculated distance to 17 Ursae Minoris as 765.64 light years away from Earth or 234.74 parsecs. If you want that in miles, it is about 4,500,910,730,724,299.16, based on 1 Ly = 5,878,625,373,183.61 miles.

In 2007, Hipparcos data was revised with a new parallax of 5.20000 which put 17 Ursae Minoris at a distance of 627.24 light years or 192.31 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.

Using the 2007 distance, the star is roughly 39,666,508.49 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun. The star's Galacto-Centric Distance is 7,455.00 Parsecs or 24,315.48 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*.

Travel Time to 17 Ursae Minoris

The time it will take to travel to this star is dependent on how fast you are going. U.G. has done some calculations as to how long it will take going at differing speeds. A note about the calculations, when I'm talking about years, I'm talking non-leap years only (365 days).

The New Horizons space probe is the fastest probe that we've sent into space at the time of writing. Its primary mission was to visit Pluto which at the time of launch (2006), Pluto was still a planet.

DescriptionSpeed (m.p.h.)Time (years)
Airbus A380736571,518,443.44
Speed of Sound (Mach 1)767.269548,226,989.98
Concorde (Mach 2)1,534.54274,113,137.73
New Horizons Probe33,00012,746,593.16
Speed of Light670,616,629.00627.24

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.

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Additional 17 Ursae Minoris Facts and Figures

Visual Facts

Primary / Proper / Traditional Name17 Ursae Minoris
Alternative NamesHD 143803, HIP 77942, 17 UMi, BD+75 579
Spectral TypeG5
Constellation's Main StarNo
Multiple Star SystemNo / Unknown
Star TypeStar
GalaxyMilky Way
ConstellationUrsa Minor
Absolute Magnitude 0.03 / 0.46
Visual / Apparent Magnitude6.88
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)15h 55m 01.06
Declination (Dec.)+75° 34` 27.5
Galactic Latitude36.57806036 degrees
Galactic Longitude110.06067367 degrees
1997 Distance from Earth4.26000 Parallax (milliarcseconds)
 765.64 Light Years
 234.74 Parsecs
2007 Distance from Earth5.20000 Parallax (milliarcseconds)
 627.24 Light Years
 192.31 Parsecs
 39,666,508.49 Astronomical Units
Galacto-Centric Distance24,315.48 Light Years / 7,455.00 Parsecs
Proper Motion Dec.-9.59000 ± 0.36000 milliarcseconds/year
Proper Motion RA.17.45000 ± 0.38000 milliarcseconds/year
B-V Index0.83
Radial Velocity-18.90000 ± 3.00 km/s
Semi-Major Axis8466.0000000
Stellar Luminosity (Lsun)67.9900000

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Calculated Facts

Radius (x the Sun)8.78
Effective Temperature5,353 Kelvin

Sources and Links

SIMBAD SourceLink

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Comments and Questions

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