Measuring Optical Extinction Towards Young Stellar Objects Using Diffuse Interstellar Bands

Abstract

Line-of-sight extinction estimates to well-studied young T Tauri and Herbig Ae/Be stars are based on many different measurements and analysis methods. This has resulted in wide scatter among the published A_V values for the same star. In this work, we discuss the challenges in measuring extinction to actively accreting and especially outbursting young stellar objects (YSOs), and explore a method not previously applied to young stars, utilizing diffuse interstellar bands (DIBs). In early-type stars, narrow correlations exist between DIB equivalent widths and the column density of interstellar material, and therefore the line-of-sight extinction. Here, we measure equivalent widths of the 5780 Å and 6614 Å DIB features in a sample of actively accreting YSOs, and apply established DIB--reddening calibrations to derive reddening, and subsequently extinction. We also compare the DIBs-inferred optical line-of-sight extinction values with previous extinction estimates for our sample stars.