Sagittarius Dwarf Irregular Galaxy

Not to be confused with Sagittarius Dwarf Spheroidal Galaxy (SagDEG), a satellite galaxy of the Milky Way.

The Sagittarius Dwarf Irregular Galaxy (SagDIG) is a dwarf galaxy in the constellation of Sagittarius. It lies about 3.4 million light-years away. It was discovered by Cesarsky^[who?] et al. on a photographic plate taken for the ESO (B) Atlas on 13 June 1977 using the ESO 1 meter Schmidt telescope.

SagDIG
SagDIG by Hubble Space Telescope
Observation data (J2000 epoch)
Constellation	Sagittarius
Right ascension	19h 29m 59.0s[1]
Declination	−17° 40′ 41″[1]
Redshift	−79±1 km/s[1]
Distance	3.39±0.23 Mly (1.04±0.07 Mpc)[2][3]
Apparent magnitude (V)	15.5[1]
Characteristics
Type	IB(s)m[1] V (Dwarf irregular galaxy)
Apparent size (V)	2.9′ × 2.1′[1]
Other designations
Sagittarius Dwarf Irregular,[1] SGR Dwarf,[1] ESO594-G004,[1] PGC 63287,[1] Kowal's Object[1]

The SagDIG is thought to be the member of the Local Group most remote from the Local Group's barycenter. It is only slightly outside the zero-velocity surface of the Local Group.^[4]

SagDIG is a much more luminous galaxy than the Aquarius Dwarf and it has been through a prolonged period of star formation.^[5] 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 [Fe/H] ≤ −1.3). Further, the population is young, with the most likely average age between 4 and 8 billion years for the dominant population.^[6]