NOAO >   Observing Info >   Approved Programs >   2012B-0253

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Proposal Information for 2012B-0253


PI: Mike Reed, Missouri State University, mikereed@missouristate.edu
Address: Physics Department, 901 S. National, Springfield, MO 65897, USA

CoI: Andrzej Baran, Missouri State University
CoI: Roy Ostensen, KU Leuven, Belgium
CoI: Simon O'Toole, Australian Astronomical Observatory

Title: Testing theoretical models of subdwarf B stars using multicolor photometry

Abstract: Pulsating stars allow a direct investigation of their structure and evolutionary history from the evaluation of pulsation modes. However, the observed pulsation frequencies must first be identified with spherical harmonics (modes). For subdwarfs B (sdB) stars, such identifications using white light photometry currently have significant limitations. We intend to use multicolor photometry to identify pulsation modes and constrain structure models. We propose to observe the pulsating sdB star PG0154+182 (BI Ari) with our multicolor instrument GT Cam. Our observations will be compared with perturbative atmospheric models (BRUCE/KYLIE) to identify the pulsation modes. This is part of our NSF grant to obtain seismic tools to test structure and evolution models; constraining stellar parameters including total mass, envelope mass, internal composition discontinuities and internal rotation. During winter/spring 2012, we were allocated three runs on the 2.1 m to collect multicolor data on other promising pulsating subdwarf B stars as part of this work. Those runs were very successful, prompting our continued proposals. In addition, we will obtain 3-color data using MAIA on the Mercator Telescope (using guaranteed institutional time).


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NOAO >   Observing Info >   Approved Programs >   2012B-0253

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