Universe Guide


55 Leonis - HD94672 - HIP53423

55 Leonis is a blue to white giant star that can be located in the constellation of Leo. HIP53423 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD94672. The Id of the star in the Gould Star Catalogue is 22. Stars in the southern hemisphere are more likely to have a Gould Id than the northern hemisphere. For example, there are no Gould classified stars in Ursa Major. 55 Leonis has alternative name(s), 55 Leonis , 55 Leo. 55 Leonis is a multiple star system with 2 stars orbiting in its solar system.

Location of 55 Leonis

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 55 Leonis, the location is 10h 55m 42.34 and +00d44`13.0 .

Proper Motion of 55 Leonis

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 -002.90 ± 000.31 towards the north and 103.98 ± 000.48 east if we saw them in the horizon.

Physical Properties (Colour, Temperature, Radius) of 55 Leonis

55 Leonis has a spectral type of F2III. This means the star is a blue to white giant star. The star has a B-V Colour Index of 0.42 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 6,635 Kelvin.

55 Leonis has been calculated as 2.04 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 1,418,010.57.km.

55 Leonis Apparent and Absolute Magnitudes

55 Leonis has an apparent magnitude of 5.91 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 2.70 If you used the 2007 Parallax value, you would get an absolute magnitude of 2.65. 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 55 Leonis

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 22.85 which gave the calculated distance to 55 Leonis as 142.74 light years away from Earth or 43.76 parsecs. It would take a spaceship travelling at the speed of light, 142.74 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 22.29 which put 55 Leonis at a distance of 146.33 light years or 44.86 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.

55 Leonis Facts

Alternative Names

Traditional Name55 Leonis
Short Name55 Leo
Alternative Name(s)55 Leonis
Hipparcos Library I.D.53423
Bonner DurchmusterungBD+01 2501
Gould I.D.22
Henry Draper Designation94672

Visual Facts

Star Typegiant star
Absolute Magnitude2.70 / 2.65
Apparent Magnitude5.91
Right Ascension (R.A.)10h 55m 42.34
Declination (Dec.)+00d44`13.0
1997 Distance from Earth22.85 Parallax (milliarcseconds)
 142.74 Light Years
 43.76 Parsecs
2007 Revised Distance from Earth22.29 Parallax (milliarcseconds)
 146.33 Light Years
 44.86 Parsecs
Proper Motion Dec.-2.90 ± 0.31 milliarcseconds/year
Proper Motion RA.103.98 ± 0.48 milliarcseconds/year
B-V Index0.42
Spectral TypeF2III
Colour(F) blue to white
Stars in Solar System2

Estimated Facts

Radius (x the Sun)2.04
Calculated Effective Temperature6,635 Kelvin

Sources and Links

SIMBAD SourceLink

Related Stars

Multi-Star System

The star has been identified as being a multi-star system, one in which there is at least one star in close orbit to another star or two or more stars orbiting a central point. The stars may be of equal mass, unequal mass where one star is stronger than the other or be in groups orbiting a central point which doesn't necessarily have to be a star. More information can be found on my dedicated multiple star systems page. The source of the info is Simbad. The file is dated 2000 so any differences between this and any other source will be down to the actual source from where the information came from.

Proper Motion mas/yr
H.D. IdB.D. IdStar CodeMagnitudeR.A.Dec.SpectrumColourYear
94672+01 2501.0A6.0000097.000003.00000F2Yellow/White

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