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Algieba, Gamma Leonis, 41 Leonis, HD89484, HIP50583, HR4057

Algieba (Gamma Leonis) Location in Leo

Algieba (Gamma Leonis) is a orange to red giant star that can be located in the constellation of Leo. The description is based on the spectral class. Algieba is a main star of the constellation.

Algieba is the 50th brightest star in the night sky and the 2nd brightest star in Leo based on the Hipparcos 2007 apparent magnitude. The star can be seen with the naked eye, that is, you don't need a telescope/binoculars to see it. Algieba has at least 1 Extrasolar Planets believed to be in orbit around the star.

If Algieba was in a galaxy far far away, it would be a strong contender for containing a similar planet to Tatooine, the home planet of Luke Skywalker from star Wars. Although the exoplanet that is detailed here is a gas giant, its quite possible that the star could have a rocky planet because rocky planets such as our Earth and Mars are small and not easy to spot. Whilst some rocky planets have been spotted, small rocky planets are still to be spotted.

Algieba's Alternative Names

Gamma Leonis (Gam01 Leo) is the Bayer Classification for the star. The Id of the star in the Yale Bright Star Catalogue is HR4057. HIP50583 is the reference name for the star in the Hipparcos Star Catalogue. The Id of the star in the Henry Draper catalogue is HD89484.

Algieba has alternative name(s) :- , NSV 04823.

Flamsteed designations are named after the creator, Sir John Flamsteed. Sir John numbered the stars in the constellation with a number and the latin name, this star's Flamsteed designation is 41 Leonis with it shortened to 41 Leo.

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+20 2467.

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

Location of Algieba

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 Algieba, the location is 10h 19m 58.16 and +19° 50` 30.7 .

Radial Velocity and Proper Motion of Algieba

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 -154.28 ± 0.32 miliarcseconds/year towards the north and 304.30 ± 0.52 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 the Sun is -36.24 km/s with an error of about 0.18 km/s . When the value is negative then the star and the Sun are getting closer to one another, likewise, a positive number means that two stars are moving away. Its nothing to fear as the stars are so far apart, they won't collide in our life-time, if ever.

Algieba Luminosity

Luminosity is the amount of energy that a star pumps out and its relative to the amount that our star, the Sun gives out. The figure of 343.59 that I have given is based on the value in the Simbad Hipparcos Extended Catalogue at the University of Strasbourg from 2012.

Physical Properties (Colour, Temperature, Mass) of Algieba

Algieba has a spectral type of K0III. This means the star is a orange to red giant star. The star is 7,419.00 Parsecs from the Galactic Centre or terms of Light Years is 24,198.06 s. The star has a B-V Colour Index of 1.12 which means the star's temperature has been calculated using information from Morgans @ Uni.edu at being 4,628 Kelvin.

Algieba Radius has been calculated as being 22.19 times bigger than the Sun.The Sun's radius is 695,800km, therefore the star's radius is an estimated 15,438,679.86.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 22.92. The figure is derived at by using the formula from SDSS and has been known to produce widely incorrect figures. The star's solar mass is 1.23 times that of the Sun's. The Sun's Mass is 1,989,100,000,000,000,000,000 billion kg. which to calculate using this website is too large. To give idea of size, the Sun is 99.86% the mass of the solar system.

The star's metallicity is -0.510000, this value is the fractional amount of the star that is not Hydrogen (X) or Helium (Y). An older star would have a high metallicity whereas a new star would have a lower one.

Algieba Apparent and Absolute Magnitudes

Algieba has an apparent magnitude of 2.01 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 -0.92 If you used the 2007 Parallax value, you would get an absolute magnitude of -0.99. 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 Algieba

Using the original Hipparcos data that was released in 1997, the parallax to the star was given as 25.96 which gave the calculated distance to Algieba as 125.64 light years away from Earth or 38.52 parsecs. It would take a spaceship travelling at the speed of light, 125.64 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 25.07 which put Algieba at a distance of 130.10 light years or 39.89 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.

Using the 2007 distance, the star is roughly 8,227,845.79 Astronomical Units from the Earth/Sun give or take a few. An Astronomical Unit is the distance between Earth and the Sun. The number of A.U. is the number of times that the star is from the Earth compared to the Sun.

The star's Galacto-Centric Distance is 7,419.00 Parsecs or 24,198.06 Light Years. The Galacto-Centric Distance is the distance from the star to the Centre of the Galaxy which is Sagittarius A*. Algieba brightness ranges from a magnitude of 2.200 to a magnitude of 2.160 over its variable period. The smaller the magnitude, the brighter the star. Its variable/pulsating period lasts for 0.0 days (variability).

Meteor Showers Radiating from near Algieba

The Gamma Leonids Meteor Shower radiants from a point near this star. The meteor shower runs typically between Aug 14-Sept 12 with a peak date of Aug. 25/26.

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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Algieba Facts

Visual Facts


Primary / Proper / Traditional NameAlgieba
Alternative NamesGamma Leonis, Gam01 Leo, HD 89484, HIP 50583, HR 4057, 41 Leonis, 41 Leo, BD+20 2467, NSV 04823
Spectral TypeK0III
Constellation's Main StarYes
Multiple Star SystemYes
Star TypeGiant Star
Colour orange to red
GalaxyMilky Way
ConstellationLeo
Absolute Magnitude -0.92 / -0.99
Visual / Apparent Magnitude2.01
Naked Eye VisibleYes - Magnitudes
Right Ascension (R.A.)10h 19m 58.16
Declination (Dec.)+19° 50` 30.7
Galactic Latitude54.65 degrees
Galactic Longitude216.55 degrees
1997 Distance from Earth25.96 Parallax (milliarcseconds)
 125.64 Light Years
 38.52 Parsecs
2007 Distance from Earth25.07 Parallax (milliarcseconds)
 130.10 Light Years
 39.89 Parsecs
 8,227,845.79 Astronomical Units
Galacto-Centric Distance24,198.06 Light Years / 7,419.00 Parsecs
Proper Motion Dec.-154.28 ± 0.32 milliarcseconds/year
Proper Motion RA.304.30 ± 0.52 milliarcseconds/year
B-V Index1.12
Radial Velocity-36.24 ± 0.18 km/s
Eccentricity0.46
Semi-Major Axis9295.00
Stellar Luminosity (Lsun)343.59
Brightest in Night Sky50th
Associated / Clustered StarsAd Leonis
Algieba B

Companions (Multi-Star and Exoplanets) Facts


Exoplanet Count1

Variable Star Details


Mean Variability Period in Days0.021
Variable Magnitude Range (Brighter - Dimmer)2.160 - 2.200

Estimated Facts


Calculated Effective Temperature4,628 Kelvin
Mass Compared to the Sun1.23

Sources and Links


SIMBAD SourceLink

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
89484+20 2467.0A2.60000306.00000-153.00000K0Orange
89485B3.80000309.00000-173.00000K0Orange1831
+20 2465.0C9.60000-504.00000-62.000001915
+20 2464.0D10.00000-13.00000-43.000001904

List of Extrasolar Planets orbiting Algieba


NameStatusMass (Jupiters)Orbital Period (Days)EccentricityDiscoveredSemi-Major AxisPeriastronInclination
gamma 1 Leo bConfirmed56.1428.5000.14420091.19206.700172.100

Related Stars

Algieba Solar System


This is a N.A.S.A. impression of what the solar system might look like. If the star is not on display, its because its so small compared to the orbits of the outer planets. The green area denotes the habital zone which if the planet is within that area, life could exist. The habital zone might not appear on the picture because its outside the area for the picture. Our planets show the orbit of the planet if its was in our solar system. For more information about the planet and other exoplanetary stuff, visit N.A.S.A.

Algieba Solar System

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