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T Ursae Majoris, HD109729, HIP61532

T Ursae Majoris is a red pulsating giant star that can be located in the constellation of Ursa Major. The description is based on the spectral class. The star can not be seen by the naked eye, you need a telescope to see it.

T Ursae Majoris's Alternative Names

HIP61532 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD109729.

T Ursae Majoris has alternative name(s) :- , T UMa.

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+60 1406.

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

Location of T Ursae Majoris

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 star is compared to the celestial equator and is expressed in degrees. For T Ursae Majoris, the location is 12h 36m 23.48 and +59° 29` 13.0 .

Proper Motion of T 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 -8.01 ± 0.97 miliarcseconds/year towards the north and -15.92 ± 1.39 miliarcseconds/year east if we saw them in the horizon. The Radial Velocity, that is the speed at which the star is moving away/towards us is -91.63000 km/s with an error of about 0.67 km/s .

Physical Properties (Colour, Temperature) of T Ursae Majoris

T Ursae Majoris has a spectral type of M4IIIe-M7e. This means the star is a red giant star. The star has a B-V Colour Index of 1.21 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,472 Kelvin.

T Ursae Majoris Apparent and Absolute Magnitudes

T Ursae Majoris has an apparent magnitude of 8.83 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 If you used the 2007 Parallax value, you would get an absolute magnitude of -1.65. 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 T Ursae Majoris

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as -0.55 which gave the calculated distance to T Ursae Majoris as -5930.24 light years away from Earth or -1818.18 parsecs. It would take a spaceship travelling at the speed of light, -5930.24 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 0.80 which put T Ursae Majoris at a distance of 4077.04 light years or 1250 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.

Variable Type of T Ursae Majoris

The star is a pulsating Omicron Ceti variable type which means that its size changes over time. The Variable Type is usually named after the first star of that type to be spotted. T Ursae Majoris brightness ranges from a magnitude of 11.770 to a magnitude of 7.643 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 258.5 days (variability).

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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T Ursae Majoris Facts

Visual Facts

Primary / Proper / Traditional NameT Ursae Majoris
Alternative NamesHD 109729, HIP 61532, BD+60 1406, T UMa
Spectral TypeM4IIIe-M7e
Multiple Star SystemNo / Unknown
Star TypeGiant Star
Colour red
GalaxyMilky Way
ConstellationUrsa Major
Visual / Apparent Magnitude8.83
Naked Eye VisibleRequires a 7x50 Binoculars - Magnitudes
Right Ascension (R.A.)12h 36m 23.48
Declination (Dec.)+59° 29` 13.0
Galactic Latitude57.54 degrees
Galactic Longitude126.49 degrees
1997 Distance from Earth-0.55 Parallax (milliarcseconds)
 -5930.24 Light Years
 -1818.18 Parsecs
2007 Distance from Earth0.80 Parallax (milliarcseconds)
 4077.04 Light Years
 1250 Parsecs
Proper Motion Dec.-8.01 ± 0.97 milliarcseconds/year
Proper Motion RA.-15.92 ± 1.39 milliarcseconds/year
B-V Index1.21
Radial Velocity-91.63 ± 0.67 km/s

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeOmicron Ceti
Mean Variability Period in Days258.500
Variable Magnitude Range (Brighter - Dimmer)7.643 - 11.770

Estimated Facts

Calculated Effective Temperature4,472 Kelvin

Sources and Links

SIMBAD SourceLink

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