NOAO >   Observing Info >   Approved Programs >   2013A-0491

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Proposal Information for 2013A-0491


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

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 stars PG1325+101 (QQ Vir). We were allocated time during 2012A, but because of inclement weather, we (successfully) observed a back-up target instead. Our updated instrument has a wider FoV, which will allow additional comparison stars and therefore we would be able to use non-photometric conditions. With multicolor photometry, we will use perturbative atmospheric models (BRUCE/KYLIE) to identify the pulsation frequencies. 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. We have had four runs at KPNO during 2012 and our data measure amplitude differences between filters. Our collaborators are producing atmospheric models and we expect publications early in 2013.


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NOAO >   Observing Info >   Approved Programs >   2013A-0491

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