THE RESOLVED STELLAR POPULATION OF LEO-A

New observations of the resolved stellar population of the extremely m etal-poor Magellanic dwarf irregular galaxy Leo A in Thuan-Gunn r, g, i, and narrowband Ha filters are presented. Using the recent Cepheid v ariable star distance determination to Leo A by Hoessel et al., we are able to create an accurate color-magnitude diagram (CMD). We have use d the Bavesian inference method described by Tolstoy & Saha to calcula te the likelihood of a Monte Carlo simulation of the stellar populatio n of Leo A being a good match to the data within the well understood e rrors in the data. The magnitude limits on our data are sensitive enou gh to look back at similar to 1 Gyr of star formation history at the d istance of Leo A. To explain the observed ratio of red to blue stars i n the observed CMD, it is necessary to invoke either a steadily decrea sing star formation rate toward the present lime or gaps in the star f ormation history. We also compare the properties of the observed stell ar population with the known spatial distribution of the H I gas and H II regions to support the conclusions from CMD modeling. We consider the possibility that currently there is a period of diminished star fo rmation in Leo A, as evidenced by the lack of very young stars in the CMD and the faint H Ir regions. How the chaotic II I distribution, wit h no observable rotation, fits into our picture of the evolution of Le o A is as yet unclear.