Astro Tuesday Series
Astro Tuesday Series:
  1. Informal blackboard "ChalkTalk" presentations at noon-1PM in the Hubble Lounge (ERC 501). There are nominally two 30-minute long presentations every week. Some food will be provided. To sign up, please email Leslie Rogers or Damiano Caprioli.
  2. Forma 1-hr long lunch-time seminars are scheduled occasionally, and these will be held in the ERC 576.

Current & Future Astro Tuesday Series
January 16, 2018Tuesday SeminarRachael Roettenbacher, Surveying Spotted Stars with Photometric, Spectroscopic, and Interferometric Observations

Surveying Spotted Stars with Photometric, Spectroscopic, and Interferometric Observations
January 16, 2018 | ERC 576 | 12:00 PM
Click on the image to enlarge
Rachael Roettenbacher, Stockholm University

For stars with convective outer layers, stellar magnetism manifests as dark starspots -- localized regions of stifled convection. Starspots affect measurements of fundamental stellar parameters, including temperature and radius, which lead to inaccurate estimates of age and mass. Additionally, starspots have been shown to mimic and obscure detections of planets. By imaging stellar surfaces, we begin to disentangle the signatures of stellar magnetism. The imaging efforts discussed here feature aperture synthesis imaging using interferometric data collected with the Michigan Infrared Combiner (MIRC) at Georgia State University's Center for High Angular Resolution Astronomy (CHARA) Array with sub-milliarcsecond resolution. We characterize active RS CVn binary systems and detect magnetic structures across the surface of the giant primary stars. We compare the results to simultaneous Doppler and light curve inversion imaging. The observed global regions of suppressed convection likely affect stellar parameter estimates by altering the structure of the photosphere. Extensions of this study will survey spotted stars in order to understand how stellar magnetism affects stellar parameters, impacts the evidence of companions and their characterization, accounts for long-term changes in the flux of active stars, and differs from the Sun for stars with large convective envelopes.