Cataloging and Analysis of Young Stellar Objects in the Spider Nebula (IC 417) Using Archival Visible and Infrared Data

The Spider Nebula (IC417) is a star-forming region (SFR) at ~2.3 kpc away, in the direction of the galactic anticenter. The structure of the nebulosity in IC417 is striking; there is a “stream” of texture in the nebulosity, known as the “Nebulous Stream” (NS), first noted in the NIR by Jose et al. (2008). Particularly in the infrared, four clumps of red point sources are immediately obvious in the NS. A 2015 NITARP team began work in this region, selecting new young stellar object candidates (YSOc) based on WISE infrared (IR) excess and assessing the IR properties of the literature YSOc. (The literature YSOc have been identified based on IR excess, H-alpha excess, variability, or prior identification as O/B stars.)

In 2020, we updated the list of literature YSOc to reflect more recent papers, and selected red sources from the NS based on projected position in the sky. For literature YSOc and for YSOc in the NS, we assembled available optical and infrared photometric data from up to 27 bands (including PanSTARRS, Gaia, IPHAS, 2MASS, Spitzer/IRAC, WISE, plus optical from Jose et al. 2008), and assessed images and spectral energy distributions (SEDs) of those YSOc.

In 2021, we have now included more literature YSOc and continued to assess our confidence in the YSOc, now including position in numerous color-color and color-magnitude diagrams and Gaia distances. We now have a list of 710 YSOc which we have ranked in terms of how confident we are that they are YSOs in IC417; we regard 512 of them (72%) as likely YSOs