[MWF2010] L6022 , the SIMBAD biblio

26 asymptotic giant branch (AGB) variables are identified in the Local Group galaxy Leo I. These include seven Mira and five semiregular variables for which periods, amplitudes and mean magnitudes are determined. The large range of periods for the Miras, 158 < P < 523d, suggests an AGB spanning a significant age range. The youngest must be around 1.6Gyr while the oldest could be 10Gyr or more. Two of these old Miras are found in the outer regions of Leo I (over 490arcsec from the centre) where stars on the extended AGB are rare. They could provide an interesting test of third dredge-up and mass-loss in old stars with low metallicity, and are worth further detailed investigation. At least two stars, one a Mira and the other an irregular variable, are undergoing obscuration events due to dust ejection.

An application of the Mira period-luminosity relation to these stars yields a distance modulus for Leo I of (m - M)₀= 21.80±0.11mag (internal),±0.12 (total) (on a scale that puts the Large Magellanic Cloud at 18.39mag) in good agreement with other determinations.