Leo I - Dwarf Galaxy
Leo I is a lenticular dwarf galaxy in the constellation Leo with an apparent magnitude of 11.2mag and an extent of 9.8'x7.4', that is situated only 12
arcminutes away from Regulus. It was first discovered in 1950 by Albert Georg Wilson using a 48" Schmidt- Telescope.
The galaxy is 820,000 light-years away from Earth and has a diameter of 2,300 light-years. The mass could be determined to 20 million solar
masses. It could also be shown that the galaxy does not rotate. In the center there is a supermassive black hole (SMBH) of about 3 million solar
masses. The total brightness of Leo I is M= -12.0mag, which corresponds to a luminosity of 5.4 million suns. The galaxy is embedded in an ionized
gas cloud with also 20 million solar masses. Globular clusters were not discovered so far.
The about 10 million stars in Leo I have a very low metallicity, which is only 1% of the value of the Sun. 70-80% of all stars were formed in two
violent starburst phases 6 billion and 2 billion years ago. This makes Leo I the youngest dwarf galaxy of the local group.
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Leo I needs a dark sky and a low magnification for a successful observation. On a cold, clear February night, I was able to observe this dwarf
galaxy with my 20" telescope.
Looking through the eyepiece at a magnification of 120x revealed a very faint, oval patch of light that is relatively large and was also easy
to see with averted vision. The brightness increases only slightly towards the center. Besides that, no other details could be made out, not even at a
magnification of 210x. A bit of a disturbance is Regulus, which lies just outside the field of view (bottom).
