Luminous and Variable Stars in NGC 2403 and M81

Roberta M.. Humphreys, Sarah Stangl, Michael S. Gordon, Kris Davidson, and Skyler H. Grammer

Minnesota Institute for Astrophysics, University of Minnesota

We present the results of spectroscopy and multi-wavelength photometry of luminous and variable star candidates in the nearby spiral galaxies NGC 2403 and M81. We discuss specific classes of stars, the Luminous Blue Variables (LBVs), B[e] supergiants (sgB[e]), and the high luminosity yellow hypergiants. We identify two new LBV candidates, and three sgB[e] stars in M81. We also find that some stars previously considered LBV candidates are actually field stars. The confirmed and candidate LBVs and sgB[e] stars together with the other confirmed members are shown on the HR Diagrams for their respective galaxies. We also present the HR Diagrams for the two ``SN impostors'', V37 (SN2002kg) and V12(SN1954J) in NGC 2403 and the stars in their immediate environments.

Reference: Astronomical Journal
Status: Manuscript has been accepted