Set of 2D distance–extinction stellar posteriors toward the Perseus molecular cloud (l = 159.°3, b = −20.°6) after incorporating parallax measurements from Gaia DR2 (see Section 3.1). The most probable distance and extinction to each star is marked with a red cross in each panel. For high signal-to-noise parallaxes, the Gaia DR2 data alone can significantly constrain the distance modulus (panels 1, 7, 8, and 14). However, even for parallaxes with more moderate signal-to-noise measurements, the Gaia DR2 data help break degeneracies between a star being a nearby “dwarf” or a faraway “giant” by significantly favoring one solution over the other (panels 3, 9, 11, and 15). An interactive version of this figure showing the differences before and after Gaia is available at https://faun.rc.fas.harvard.edu/czucker/Paper_Figures/stellar_post_comp.html and online.

An interactive version of this figure is available in the online journal.