Institute of Astronomy

Studying Binary Populations with Eclipsing Binaries in the GAIA Era

SpeakerTalk DateTalk Series
Nami Mowlavi25 July 2016Binary Stars Talks

Abstract

Launched at the end of 2013, ESA’s Gaia mission is repeatedly observing more than one billion stars. Several millions of them are expected to be eclipsing binaries, for which light curves, red and blue spectro-photometry, astrometry, and, depending on their brightness, stellar parameters, and radial velocity curves will be provided. This unprecedented all-sky sample of eclipsing binary systems will provide a detailed census of stellar populations as a function of galactic latitude in the Milky Way, as well as in the Magellanic Clouds, and will offer a unique opportunity to study binary systems in different states of evolution.

Pilot studies using real Kepler data resampled according to Gaia scanning law predict a successful detection and determination of the ephemerides for about half of eclipsing systems. The procedure implemented in Gaia’s Data Processing and Analysis Consortium identifies binary systems, finds their orbital periods, and computes eclipse widths and depths, inter-eclipse duration, inter-eclipse variability properties based on their light curve morphology. Several classification schemes are investigated, either based directly on the eclipsing binary parameters, or specific algorithms such as t-SNE (t-distributed Stochastic Neighbor Embedding), DBSCAN (Density-Based Spatial Clustering of Applications with Noise) or FPCA (Functional Principal Component Analysis), paving the road for a statistical analysis of binary populations. A realistic Roche model will subsequently be used to fit all available data (light curves, radial velocity curves for some of the brighter objects, as well as any other Gaia-derived quantity that constrains the system), with the aim of obtaining as much information about the physical parameters of the binary as allowed by the data.

We illustrate the method on eclipsing binary data collected by OGLE, Hipparcos and Kepler surveys, and present expectations for Gaia.

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