The Sagittarius Dwarf Irregular Galaxy or SagDIG is a dwarf galaxy in the constellation of Sagittarius. It lies about 3.4 million light-years away. SagDIG should not be confused with the Sagittarius Dwarf Elliptical Galaxy or SagDEG, a satellite galaxy of the Milky Way. It was discovered by Cesarsky et al. on a photographic plate taken for the ESO (B) Atlas on June 13, 1977 using the ESO 1 meter Schmidt telescope.
The SagDIG is the most remote object from the barycenter thought to be a member of the Local Group. It is only slightly outside the zero-velocity surface of the Local Group.
SagDIG is a much more luminous galaxy than Aquarius Dwarf and it has been through a prolonged star formation (Momany et al. 2005). This has resulted in it containing a rich intermediate-age population of stars. Twenty-seven candidate carbon stars have been identified inside SagDIG. Analysis shows that the underlying stellar population of SagDIG is metal-poor (at least ≤ −1.3). Further, the population is young, with the most likely average age between 4 and 8 Gyr for the dominant population.
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