SIMBAD references

Time-series photometry in the I and J bands of 57 inner Galactic late-type stars, highly probable red supergiant (RSG) stars, is presented here. 38% of the sample presents significant photometric variations. The variations in the I and J bands appear to be correlated, with ΔI ∝ ΔJ × 2.2, ΔI variations ranging from 0.04-1.08 mag, and ΔJ variations from 0.03-0.52 mag. New short periods (<1000 d) could be estimated for eight stars and range from 167-433 d. This work confirms that the sample is not contaminated by large-amplitude asymptotic giant branch stars. Furthermore, despite the large errors in distance, the period-luminosity diagram suggests that the sample is populating the same sequence as the known Galactic RSGs.