[6][7] The proximity of Regulus and the low surface brightness make it a real challenge to observe.

Medium-sized amateur telescopes (15 cm or more) and a dark sky appear to be required for a sighting.

The results are not conclusive, and do not exclude or confirm the existence of a large dark matter halo around the galaxy.

[7] A kinematic study of Leo I could not place much constraints on dark matter, but suggested the presence of a black hole of three million solar masses in the center of the galaxy.

About 1 Ga ago, star formation in Leo I appears to have dropped suddenly to an almost negligible rate, roughly coinciding with its latest periastron passage of the Milky Way.