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U Carinae - HD95109 - HIP53589

U Carinae is a white to yellow pulsating very luminous supergiant star that can be located in the constellation of Carina. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

HIP53589 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD95109.

U Carinae has alternative name(s), U_Car.

Location of U Carinae

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 U Carinae, the location is 10h 57m 48.19 and -59d43`55.9 .

Proper Motion of U Carinae

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 1.89 ± 0.48 miliarcseconds/year towards the north and -5.74 ± 0.56 miliarcseconds/year east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of U Carinae

U Carinae has a spectral type of G3Ia. This means the star is a white to yellow supergiant star. The star has a B-V Colour Index of 0.84 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,331 Kelvin. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

U Carinae Apparent and Absolute Magnitudes

U Carinae has an apparent magnitude of 6.36 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 -7.03. 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 U Carinae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as -0.04 which gave the calculated distance to U Carinae as -81540.84 light years away from Earth or -25000 parsecs. It would take a spaceship travelling at the speed of light, -81540.84 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 0.21 which put U Carinae at a distance of 15531.59 light years or 4761.90 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 U Carinae

The star is a pulsating Delta Cepheid 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. U Carinae brightness ranges from a magnitude of 7.000 to a magnitude of 6.000 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 39.0 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.

U Carinae Facts

Alternative Names

Traditional/Proper NameU Carinae
Short NameU Car
Hipparcos Library I.D.53589
Henry Draper Designation95109

Visual Facts

Star Typesupergiant star
Visual / Apparent Magnitude6.36
Naked Eye VisibleYes - Ref: Wiki
Right Ascension (R.A.)10h 57m 48.19
Declination (Dec.)-59d43`55.9
Galactic Latitude0.04 degrees
Galactic Longitude289.06 degrees
1997 Distance from Earth-0.04 Parallax (milliarcseconds)
 -81540.84 Light Years
 -25000 Parsecs
2007 Revised Distance from Earth0.21 Parallax (milliarcseconds)
 15531.59 Light Years
 4761.90 Parsecs
Proper Motion Dec.1.89 ± 0.48 milliarcseconds/year
Proper Motion RA.-5.74 ± 0.56 milliarcseconds/year
B-V Index0.84
Radial Velocity1.70 ± 2.30 km/s
Spectral TypeG3Ia
Colour(G) White to Yellow

Variable Star Details

Variable Star ClassPulsating
Variable Star TypeDelta Cepheid
Mean Variability Period in Days39.000
Variable Magnitude Range (Brighter - Dimmer)6.000 - 7.000

Estimated Facts

Calculated Effective Temperature5,331 Kelvin

Sources and Links

SIMBAD SourceLink

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