PI: Hilding Neilson, University of Toronto, email@example.com
Address: Department of Astronomy, 60 ST GEORGE STREET, TORONTO, ON M5S 1A1 Canada
CoI: Scott Engle, Villanova U.
CoI: Nancy Evans, Harvard-Smithsonian Center for Astrophysics
CoI: Edward F Guinan, Villanova U.
CoI: Jennifer L Hoffman, U. of Denver
CoI: Richard Ignace, E. Tennessee State U.
CoI: John Lester, University of Toronto
CoI: Massimo Marengo, Iowa State U.
CoI: Lynn Matthews, Haystack Observatory
CoI: Max Millar-Blanchaer, University of Toronto
CoI: Manisha Shrestha, U. of Denver
CoI: Beverly Smith, E. Tennessee State U.
CoI: Doug Welch, McMaster U.
Title: Gemini Planet Imager Classical Cepheid Survey
Abstract: Classical Cepheids are powerful tools for studying both stellar evolution and cosmology, thanks to their pulsation and the corresponding Leavitt Law. In the next decade, with the launch of the James Webb Space Telescope, there will be opportunities to measure the Hubble Constant to about 1% precision at infrared wavelengths. But, our ability to achieve this precision is limited by how well we understand Cepheid properties and their circumstellar media. There is growing evidence that Cepheids have infrared excesses due to a stellar wind with an unknown driving mechanism. We propose new GPI observations of a sample Galactic Cepheids to resolve the inner region of the wind to test the hypothesis that the wind is driven by pulsation-generated shocks that enhance the wind by orders of magnitude and to detect light echos in the circumstellar medium that can be used to test distance measurements.
Program Type: Standard/Galactic
Run 1 (2017A): GEM-SQ/GPI -- 4hrs band 2 (GS-2017A-Q-41)
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360