2017/09/18 by Shu Wang, Biwei Jiang, B. W. Jiang +3 · 25 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Cosmic dust #Extinction (optical mineralogy) #Galaxies: Formation, Evolution, Phenomena #Interstellar medium #Milky Way #Red clump #Stars #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/aa8db7
published in The Astrophysical Journal 848(2), 106 (IOP Publishing) · 28 pages, 7 figures, accepted for publication in The Astrophysical Journal
arxiv created 2017/09/18 · openalex created_date 2017/09/25 · openalex publication_date 2017/10/20 · arxiv updated 2017/11/01 · openalex updated_date 2026/08/06
Abstract Understanding the effects of dust extinction is important to properly interpret observations. The optical total-to-selective extinction ratio, , is widely used to describe extinction variations in ultraviolet and optical bands. Since the extinction curve adequately represents the average extinction law of diffuse regions in the Milky Way, it is commonly used to correct observational measurements along sightlines toward diffuse regions in the interstellar medium. However, the value may vary even along different diffuse interstellar medium sightlines. In this paper, we investigate the optical–mid-infrared (mid-IR) extinction law toward a very diffuse region at in the Galactic plane, which was selected based on a CO emission map. Adopting red clump stars as extinction tracers, we determine the optical–mid-IR extinction law for our diffuse region in two APASS bands ( ), three XSTPS-GAC bands ( ), three 2MASS bands ( ), and two WISE bands ( ). Specifically, 18 red clump stars were selected from the APOGEE–RC catalog based on spectroscopic data in order to explore the diversity of the extinction law. We find that the optical extinction curves exhibit appreciable diversity. The corresponding ranges from 1.7 to 3.8, while the mean value of 2.8 is consistent with the widely adopted average value of 3.1 for Galactic diffuse clouds. There is no apparent correlation between value and color excess in the range of interest, from 0.2 to 0.6 mag, or with specific visual extinction per kiloparsec, .