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Upsilon2 Centauri, HD122223, HIP68523, HR5260

Upsilon2 Centauri is a blue to white luminous giant star that can be located in the constellation of Centaurus. The description is based on the spectral class. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it.

Upsilon2 Centauri's Alternative Names

Upsilon2 Centauri (Ups02 Cen) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR5260. HIP68523 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD122223.

The Gould star designation is one that was designed by American astronomer, Benjamin Apthorp Gould. Gould stars are predominantly in the Southern and Equatorial constellations but do appear in northern constellations such as Bootes and Orion. The star has the designation 303 G. Centauri. There are no stars with a Gould designation in Ursa Major for example.

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

Location of Upsilon2 Centauri

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 Upsilon2 Centauri, the location is 14h 01m 43.49 and -45° 36` 12.1 .

Proper Motion of Upsilon2 Centauri

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 -16.25 ± 0.69 miliarcseconds/year towards the north and 8.64 ± 1.05 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 -7.80000 km/s with an error of about 7.40 km/s .

Physical Properties (Colour, Temperature) of Upsilon2 Centauri

Upsilon2 Centauri has a spectral type of F6II. This means the star is a blue to white luminous giant star. The star has a B-V Colour Index of 0.59 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 5,898 Kelvin.

Upsilon2 Centauri Radius has been calculated as being 16.65 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 11,587,548.03.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 47.16. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures.

Upsilon2 Centauri Apparent and Absolute Magnitudes

Upsilon2 Centauri has an apparent magnitude of 4.34 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 -1.35 If you used the 2007 Parallax value, you would get an absolute magnitude of -3.61. 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 Upsilon2 Centauri

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 7.28 which gave the calculated distance to Upsilon2 Centauri as 448.03 light years away from Earth or 137.36 parsecs. It would take a spaceship travelling at the speed of light, 448.03 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 2.57 which put Upsilon2 Centauri at a distance of 1269.12 light years or 389.11 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.

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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Upsilon2 Centauri Facts

Visual Facts

 Upsilon2 Centauri
Alternative NamesUps02 Cen, HD 122223, HIP 68523, HR 5260, 303 G. Centauri
Spectral TypeF6II
Multiple Star SystemYes
Star TypeLuminous Giant Star
Colour blue to white
GalaxyMilky Way
Absolute Magnitude-1.35 / -3.61
Visual / Apparent Magnitude4.34
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)14h 01m 43.49
Declination (Dec.)-45° 36` 12.1
Galactic Latitude15.53 degrees
Galactic Longitude315.60 degrees
1997 Distance from Earth7.28 Parallax (milliarcseconds)
 448.03 Light Years
 137.36 Parsecs
2007 Distance from Earth2.57 Parallax (milliarcseconds)
 1269.12 Light Years
 389.11 Parsecs
Proper Motion Dec.-16.25 ± 0.69 milliarcseconds/year
Proper Motion RA.8.64 ± 1.05 milliarcseconds/year
B-V Index0.59
Radial Velocity-7.80 ± 7.40 km/s
Associated / Clustered StarsUpsilon1 Centauri

Companions (Multi-Star and Exoplanets) Facts

Exoplanet CountNone/Unaware

Estimated Facts

Calculated Effective Temperature5,898 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

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