0 Assigned ID: 69 ----- Attempting Submission 1 (Mon Apr 06 21:34:00 GMT 2015) ----- We propose to use data from the Panchromatic Hubble Andromeda Treasury (PHAT) survey to study the environments of luminous blue variables (LBVs) in M31. LBVs are thought to mark the immediate post-main-sequence phase of massive O-type stars, and are presumed to drive the mass loss to become H-poor Wolf-Rayet (WR) stars. Thus, one expects LBVs to be associated with other main-sequence O-type stars, most of which reside in clusters. While ground-based images of M31 have been able to identify many LBVs because they are bright and easy to recognize, ground-based data lack the sensitivity to detect individual main-sequence O-type stars. The PHAT images can easily do this, especially since these data include UV images that will pick out O-type stars. The reason we are motivated to do this study is because we have recently examined the locations of LBVs and O stars in the Milky Way and Magellanic Clouds, and have found a stunning result (Smith & Tombleson 2015). With the exception of Eta Carinae, LBVs systematically avoid O stars, and they are farther from O stars than the WR stars that are supposedly their progeny. LBVs tend to be in the middle of nowhere, and about a third of them are more than 100 pc from any O star. This degree of isolation would strongly disprove our current paradigm of massive star evolution, which relies on LBV mass loss to turn massive O-type stars into WR stars. The alternative is that binary evolution domintes their fate, and it is likely that kicks from a companion's supernova enhance their isolation. To confirm this important paradigm shift, we need to see that the trend holds in the nearest large spiral galaxy. HOT STARS 0 Regular false false false false false SUPPORTED