NOAO >   Observing Info >   Approved Programs >   2013B-0430

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Proposal Information for 2013B-0430


PI: Guy Stringfellow, University of Colorado, Guy.Stringfellow@colorado.edu
Address: Center for Astrophysics and Space Astronomy, 389 UCB, Boulder, CO 80309-0389, USA

CoI: Vasilii V. Gvaramadze, Sternberg Astronomical Institute

Title: Spectroscopy of the Central Stars Associated With New Nebulae: Discovering New LBVs and WRs

Abstract: Luminous Blue Variable (LBV) stars represent an extremely rare class of luminous massive stars with high mass loss rates. The paucity (~13) of confirmed Galactic LBV precludes determining a solid evolutionary connection between LBV and other intermediate (e.g. Ofpe/WN9, WNL) phases in the life of very massive stars. We have been conducting an optical/near-IR spectral survey of a large subset of central stars residing within newly discovered \it Spitzer nebulae accessible from the north and have identified over two dozen new candidate LBVs (cLBVs) based on spectral similarity alone. This marks a significant advancement in the study of massive stars, far outweighing the return from many studies searching for LBVs and WRs the past several decades. Confirming these as \it bona fide LBVs requires demonstrating spectroscopic and photometric (1-3 mag) variability, which we are carrying out for a subset of stars on many facilities, including the SMARTS 1.3m and 1.5m, that has already resulted in confirming one new cLBV as a \it bona fide LBV. Many of the southern shells have not yet had IR spectra obtained for their central stars, or undergone spectral monitoring. Further, we continue to discover new shell sources with central stars that require spectra for identification. Spectra are important for understanding the physics driving photometric variability, the physical conditions and structure of the wind, and in line profile analysis. We also request continuation of our photometric monitoring of a subset of cLBVs and LBVs using ANDICAM on the 1.3m.


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