AAVSO: American Association of Variable Star Observers

Engaging AAVSO members in Stellar Astrophysics Follow-up from The Evryscope Data (Abstract)

Volume 45 number 1 (2017)

Octavi Fors
Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; octavi@live.unc.edu
Nicholas M. Law
Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; octavi@live.unc.edu
Jeffrey Ratzloff
Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; octavi@live.unc.edu
Henry Corbett
Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; octavi@live.unc.edu
Daniel del Ser
Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; octavi@live.unc.edu and Departament de Física Quàntica i Astrofísica, Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Martí Franquès 1, E08028 Barcelona, Spain
Ward Howard
Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599; octavi@live.unc.edu
Stephen Cox
Renaissance Computing Institute, 100 Europa Drive, Suite 540, Chapel Hill, NC 27517

Abstract

(Abstract only) The Evryscope is a gigapixel-scale array of 24 telescopes which covers an instantaneous 8,640-square-degree field-of-view at two-minute cadence. This telescope opens a new parameter space in time-domain astronomy, trading instantaneous depth (g ~16mag) and sky sampling (~13") for continuous coverage (97% survey time efficiency) of the largest sky area of any active survey. The system is obtaining 25,000 photometric measurements per target and per year, with a per-exposure 100-degree declination range. The Evryscope photometric precision is one percent-level at two minute cadences on bright (g < 1 2) stars, and ~5 mmags ~12-minute binning. The first science case The Evryscope is undertaking is the first large-scale survey of transiting planetesimals around the 4,500+ brightest white dwarfs (WDs). As byproducts of this survey long-term measurements of WDs pulsations, eclipsing WD binaries and periodically variable WDs will be obtained. Other science cases already recorded in The Evryscope dataset and to be started analyzed in the next weeks are: transiting habitable-zone rocky planets around the ~5,000 nearby M-dwarfs, nearby microlensing events, increasing TESS long-period giant planets return, the discovery and characterization of a wide range of stellar variability, including the measure of the mass-radius relation by using a complete inventory of eclipsing binary systems, detecting young stars by their flare behavior, detecting stellar merger events, accreting compact objects, and exotic pulsators. The Evryscope was deployed at CTIO in May 2015. The telescope is fully operational, streaming raw imaging data per night at 109MB/sec. All data is stored and analyzed on-site by a high-speed server. Two more Evryscopes are planned to be deployed in near future: at Mount Laguna Observatory (collaboration with SDSU) and in the High Arctic (collaboration with NARIT and University of Toronto). The Evryscopes are capable of monitoring almost every star brighter than 16th magnitude. After the discovery of variability of any type, the next step is follow-up, whether to confirm a transiting planet, obtain multi-color light curves of a microlensing events, or cover any of the host of stellar variability phenomena. I discuss the vital role AAVSO members could have in obtaining these observations. I show some characteristic examples of the kind of variable stars light curves which are in The Evryscope dataset.