STRESS - STEREO TRansiting Exoplanet and Stellar Survey - I : Introduction and Data Pipeline

TL;DR

This paper introduces the STRESS survey, utilizing STEREO spacecraft's heliospheric imagers for high-precision stellar photometry to detect exoplanets and study stellar variability, with a focus on data pipeline and initial findings.

Contribution

It presents a new data pipeline and analysis methods for the STEREO HI instruments, enabling exoplanet transit detection and stellar variability studies from space-based wide-angle imaging.

Findings

High-precision photometry over a broad magnitude range

Large sky coverage with the STEREO instruments

Initial detection of stellar variability and potential exoplanet transits

Abstract

The Solar TErrestrial RElations Observatory - \emph{STEREO}, is a system of two identical spacecraft in Heliocentric Earth orbit. We use the two Heliospheric Imagers (HI), which are wide angle imagers with multi-baffle systems to do high precision stellar photometry in order to search for exoplanetary transits and understand stellar variables. The large cadence (40 min for HI-1 and 2 hrs for HI-2), high precision, wide magnitude range (\emph{R} mag - 4 to 12) and broad sky coverage (nearly 20 percent just for HI-1A and 60 per cent of the sky in the zodiacal region for all the instruments combined) of this instrument marks this in a space left largely devoid by other current projects. In this paper, we describe the semi-automated pipeline devised for the reduction of this data, some of the interesting characteristics of the data obtained, data analysis methods used along with some early results.