Leo I

Dwarf Spheroidal Galaxy Leo I (UGC 5470, DDO 74, A1006), type dE3, in Leo

Regulus Galaxy, Harrington-Wilson 1

RA:: 10 : 08.5
Dec:: +12 : 18
Type:: dSph, dE3
RV:: 168 +/- 60 km/s (helio.)
Distance:: 900 kly
Apparent Dimension:: 9.8 x 7.4 arc min
Diameter:
Brightness:: 9.8 m_vis, 11.2 m_ph
Abs. Mag:
Mass:

Leo I, together with Leo II, was discovered in 1950 by R.G. Harrington and A.G. Wilson on plates of the National Geographic Society - Palomar Sky Survey obtained with the 48-inch Schmidt Telescope on Mt. Palomar (see reference). According to Wilson (1955), Wilson discovered Leo I and Harrington discovered Leo II.

This dwarf galaxy was only visually detected by amateurs in the last 15 years because nearby (only about 12 arc minutes) bright (first-magnitude) Regulus shines this galaxy out despite its rather considerable brightness of 9.8 mag visually and 11.2 mag photographically.

Our image of Leo I was obtained by David Malin and is copyrighted © Australian Astronomical Observatory.

More information on this image (David Malin)

Higher-resolution (832x624 pixel) version of this image

Leo Dwarf image by Mel Bartels, obtained with a Hale camera using SITe 512x512 back illuminated chip, 6" f/5, 1 minute exposure (raw image)

Chris Schur's Leo I image - more information on this image by Chris Schur

More information on Leo I (SEDS Messier Database)

References:

R.G. Harrington and A.G. Wilson, 1950. Two New Stellar Systems in Leo. Publications of the Astronomical Society of the Pacific, Vol. 62, No. 365, p. 118 [ADS: 1950PASP...62..118H]
A.G. Wilson, 1955. Sculptor-Type Systems in the Local Group of Galaxies. Publications of the Astronomical Society of the Pacific, Vol. 67, No. 394, pp. 27-29 (02/1955) [ADS: 1955PASP...67...27W]

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Hartmut Frommert
Christine Kronberg
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Last Modification: January 13, 2000