NOAO >   Observing Info >   Approved Programs >   2015B-0295

Small NOAO Logo

Program Information for 2015B-0295


PI: Todd R Vaccaro, St. Cloud State U., trvaccaro@gmail.com
Address: Physics Department, WSB 312, 720 4th Ave. South, St. Cloud, MN 56301 USA

CoI: Geraldine J Peters, USC
CoI: Robert E Wilson, U. of Florida

Title: Orbital and Systemic Parameters for Algol Binaries in the Kepler and K2 Fields

Abstract: We propose follow-up observations of Algol-type binaries with the 4m Kosmos spectrograph that are necessary for the interpretation of photometry from the \textit{Kepler} spacecraft. Four nights were allocated in 2013A, but we effectively secured only 2 nights of data due to an instrumental setup mistake and cloudy skies. We will also now have 7 additional targets from the newer \textit{K2} fields. The Algols are direct-impact systems (periods range from 1-10 d) in which the gas stream strikes the photosphere of the gainer, producing a shock. The \textit{Kepler} light curves reveal striking long and short-term variability never before seen in ground-based observations. Especially interesting is a long-term oscillation in the relative brightness of the quadrature light that we call L/T variability, which may be caused from a migrating variable hot accretion spot on the primary or an extensive varying cool, spotted region on the secondary. The \textit{Kepler} photometry is being interpreted with an updated version of the Wilson \& Devinney (WD) program. The KPNO spectra will supply critical input parameters (e.g. temperatures) and yield velocity curves from which we will determine the masses of the stars and absolute dimensions of the systems, essential for determining whether the L/T variability is a hot or cool star phenomenon. This project will yield information on the detailed physics of mass transfer, especially the roles of accretion hot spots and magnetic fields, and also test the new WD program for future applications by others working with the \textit{Kepler} database.

Program Type: Standard/Galactic

Scheduled Nights:
Run 1 (2015B):  KP-4m/KOSMOS -- 4n on Sep 25 - Sep 28 2015


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



NOAO >   Observing Info >   Approved Programs >   2015B-0295

noaoprop-help@noao.edu

Small NOAO Logo