Mapping Young Stellar Objects in the Galactic Mid-Plane Almost all data is taken from Spitzer Space Telescope and the GLIMPSE project (Galactic Legacy Infrared Mid-Plane Survey) By Andrew Britton With Jeff Hester & Keely Snider School of Earth and Space Exploration Spitzer

Young Stellar Objects (YSOs) Defined as a star in its early stage of evolution. YSOs emit largely in Mid-Infrared wavelengths. YSOs emit visible light from the proto-star. The light then gets absorbed by dust particles in the disk surrounding the forming star. The dust particles re-emit in the infrared. Sometimes jets are formed perpendicular to the plane of the accretion disk The graph on the right shows a dashed line which is typical for main sequence stars that are well in to their life cycle. The solid line is a of a YSO, as you can see the second peak is located in the infrared area of the spectrum Robitaille et al. (2006)

YSO Candidates IRAC Color-Color Diagram for L=22-25 -The Infrared Array Camera (IRAC) is one of Spitzer’s three science instruments. -Provides imaging for mid-infrared wavelengths. -Excluded AGB & Extra Galaxies Class I/0 (Youngest) is red in all bands and has high luminosity because there is still a lot of material to be accreted onto the star. Class I/II and II are older and have lower luminosity’s as they move along the Hayashi track to hydrostatic equilibrium. Number of Candidates: Blue-1325, Red-725, Green-88

YSO Contours Color YSO Contours image with latitude of 22-25 degrees Contours show the concentration of YSOs chosen from the candidates on color plot. Red= 8, Green= 5.8, Blue= 3.6 (µm)

Panoramic Image 19-28 degrees Same parameters with near left and right three degrees of longitude of galactic mid-plane. 19-28 degrees During the construction of panorama images 0.5 degrees was overlapped to show precision.

Point sources and HII Regions Point sources show a the amount of candidates for YSOs. An H II region is a cloud of glowing gas and plasma, they may give birth to thousands of stars over several million years, (H II regions are gathered from older catalogs) All the H II regions that are displayed are less than or equal to 4 kiloparsecs (13,046.545ly)