The Star Formation History and Dust Production in Andromeda IX

Local Group (LG), the nearest and most complete galactic environment, provides valuable information on the formation and evolution of the Universe. Studying galaxies of different sizes, morphologies, and ages can provide this information. For this purpose, we chose the And IX dSph galaxy, which is one of the observational targets of the Isaac Newton Telescope (INT) survey. A total of 50 long-period variables (LPVs) were found in And IX in two filters, Sloan i' and Harris V at a half-light radius of 2.5 arcmin. The And IX's star formation history (SFH) was constructed with a maximum star formation rate (SFR) of about 0.00082 ± 0.00031 M_⊙ yr⁻¹, using LPVs as a tracer. The total mass return rate of LPVs was calculated based on the spectral energy distribution (SED) of about 2.4 × 10⁻⁴ M_⊙ yr⁻¹. The distance modulus of 24.56_−0.15^+0.05 mag was estimated based on the tip of the red giant branch (TRGB).