1318 New Variable Stars in a 0.25 Square Degree Region of the Galactic Plane

TL;DR

This study presents a deep photometric survey of a Galactic Plane region, discovering 1318 variable stars, including many eclipsing binaries, using advanced image analysis techniques over multiple years.

Contribution

Introduces a new variable star catalog in the Galactic Plane using a novel difference image analysis method with extensive temporal coverage.

Findings

Discovered 1318 variable stars, including eclipsing binaries and pre-main sequence candidates.

Identified contact binaries with low mass ratios and periods at the known cutoff.

Detected several binaries with the shortest known periods.

Abstract

We have conducted a deep photometric survey of a 0.5 deg x 0.5 deg area of the Galactic Plane using the WFI instrument on the 2.2-m ESO telescope on La Silla, Chile. The dataset comprises a total of 267 R-band images, 204 from a 16 day observation run in 2005, supplemented by 63 images from a six week period in 2002. Our reduction employed the new numerical kernel difference image analysis method as implemented in the PYSIS3 code and resulted in more than 500,000 lightcurves of stars down to a magnitude limit of R ~ 24.5. A search for variable stars resulted in the detection of 1318 variables of different types. 1011 of these are eclipsing or contact binary stars. A number of the contact binaries have low mass-ratios and several of the detached binaries appear to have low-mass components. Three candidate contact binaries have periods at the known cut off including two with periods lower than any previously published. Also identified are 3 possible pre-main sequence detached eclipsing binaries.