Calculating Velocity to Find Distance to YellowBalls to Build a Catalogue That Aids the Research of Massive Star Formation

YellowBalls (YBs) were first discovered by citizen scientists in mid-infrared images from the Spitzer Space Telescope. Their yellow color comes from a combination of green (8 $\mu$m) and red (24 $\mu$m) emission. The combined emission suggests ionization and heat, respectively, which are signs of newly forming massive or intermediate-mass stars. YBs are a potentially useful tool to expand our knowledge of star formation. We are building a catalog of YBs that includes their location, distance, size, color, mass, and luminosity, providing data for astronomers to use to learn more about YBs’ role in star formation. Distance is a crucial property to determine physical properties such as luminosity and size. I used data from the SEDIGISM and BU-GRS datasets to analyze $^{13}$CO spectra at the locations of YBs. Doppler shift of the $^{13}$CO lines indicates YB velocities. I then used the location of YBs in the Galactic plane along with Velocities in a distance calculator that combined a kinematic rotational model of the Milky Way and the Bayesian statistics to determine distance. I have determined the velocities and distances for $\sim$4000 YBs, which will be included in our final catalog.