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arXiv · 2102.01661

The Milky Way Project: Probing Star Formation with First Results on Yellowballs from DR2

Grace Wolf-Chase·C. R. Kerton·Kathryn Devine·Anupa Pouydal·Johanna Mori·Leonardo Trujillo·Aurora Cossairt·Sarah Schoultz·Tharindu Jayasinghe·Matthew Povich
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Abstract

Yellowballs (YBs) were first discovered during the Milky Way Project citizen-science initiative (MWP; Simpson et al. 2012). MWP users noticed compact, yellow regions in Spitzer Space Telescope mid-infrared (MIR) images of the Milky Way plane and asked professional astronomers to explain these "yellow balls." Follow-up work by Kerton et al. (2015) determined that YBs likely trace compact photo-dissociation regions associated with massive and intermediate-mass star formation. YBs were included as target objects in a version of the Milky Way Project launched in 2016 (Jayasinghe et al. 2016), which produced a listing of over 6000 YB locations. We have measured distances, cross-match associations, physical properties, and MIR colors of ~500 YBs within a pilot region covering the l= 30 - 40 degrees, b= +/- 1 degree region of the Galactic plane. We find 20-30% of YBs in our pilot region contain high-mass star formation capable of becoming expanding H II regions that produce MIR bubbles. A majority of YBs represent intermediate-mass star-forming regions whose placement in evolutionary diagrams suggest they are still actively accreting, and may be precursors to optically-revealed Herbig Ae/Be nebulae. Many of these intermediate-mass YBs were missed by surveys of massive star-formation tracers and thus this catalog provides information for many new sites of star formation. Future work will expand this pilot region analysis to the entire YB catalog.

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Grace Wolf-Chase, C. R. Kerton, Kathryn Devine, Anupa Pouydal, Johanna Mori, Leonardo Trujillo, Aurora Cossairt, Sarah Schoultz, Tharindu Jayasinghe, Matthew Povich. 2021-02-05. The Milky Way Project: Probing Star Formation with First Results on Yellowballs from DR2. https://doi.org/10.3847/1538-4357%2Fabe87a

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