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33 Librae - HD137949 - HIP75848

33 Librae is a blue star that can be located in the constellation of Libra. HIP75848 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD137949. 33 Librae has alternative name(s), 33 Librae , 33 Lib.

Location of 33 Librae

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 33 Librae, the location is 15h 29m 34.78 and -17d26`27.4 .

Proper Motion of 33 Librae

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 006.00 ± 000.34 towards the north and -066.70 ± 000.67 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 33 Librae

33 Librae has a spectral type of Ap. This means the star is a blue star. The star has a B-V Colour Index of 0.39 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,431 Kelvin.

33 Librae has been calculated as 3.08 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 2,141,962.02.km.

33 Librae Apparent and Absolute Magnitudes

33 Librae has an apparent magnitude of 6.69 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 1.94 If you used the 2007 Parallax value, you would get an absolute magnitude of 1.95. 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 33 Librae

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 11.21 which gave the calculated distance to 33 Librae as 290.96 light years away from Earth or 89.21 parsecs. It would take a spaceship travelling at the speed of light, 290.96 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 11.28 which put 33 Librae at a distance of 289.15 light years or 88.65 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 Stellar Age, Metallicity or Mass is from the E.U. Exoplanets. The information was obtained as of 12th Feb 2017.

33 Librae Facts

Alternative Names

Traditional Name33 Librae
Short Name33 Lib
Alternative Name(s)33 Librae
Hipparcos Library I.D.75848
Bonner DurchmusterungBD-16 4093
Henry Draper Designation137949

Visual Facts

Star Type star
Absolute Magnitude1.94 / 1.95
Apparent Magnitude6.69
Right Ascension (R.A.)15h 29m 34.78
Declination (Dec.)-17d26`27.4
1997 Distance from Earth11.21 Parallax (milliarcseconds)
 290.96 Light Years
 89.21 Parsecs
2007 Revised Distance from Earth11.28 Parallax (milliarcseconds)
 289.15 Light Years
 88.65 Parsecs
Proper Motion Dec.6.00 ± 0.34 milliarcseconds/year
Proper Motion RA.-66.70 ± 0.67 milliarcseconds/year
B-V Index0.39
Spectral TypeAp
Colour(A) blue

Estimated Facts

Radius (x the Sun)3.08
Calculated Effective Temperature6,431 Kelvin

Sources and Links

SIMBAD SourceLink

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