2025/06/30 by Jiang, Botao, Li, Jun, Chen, Xi
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR)
paper · doi:10.48550/arxiv.2506.23915
The viability of the star count (Wolf) method is assessed as a means of constraining the near-infrared (NIR) extinction law toward the Corona Australis molecular cloud. Using deep JHKS photometry from the VISIONS survey, extinction maps with 1 arcmin spatial resolution are constructed. The derived extinction ratios are AJ/AH=1.73±0.07, AH/AKS=1.70±0.11, and AJ/AKS=3.02±0.22, which are consistent with Galactic literature means. Assuming a power-law form (Aλ∝ λ-α) for the NIR extinction law, we derive indices of α≈ 2.0 across all wavelength combinations, with no statistically significant wavelength dependence throughout the NIR wavelength range. While spatial variations in extinction properties are tentatively observed across the cloud, concerns persist regarding the impact of photometric completeness, and the role of reference field selection. Continued research is required to refine the approach, and scrutinize the veracity of potential extinction law variations over a more expansive region of sky.