Air, Telescope, and Instrument Temperature Effects on the Gemini Planet Imager's Image Quality

TL;DR

This study investigates how temperature differences inside and outside the Gemini South telescope dome affect the image quality of the Gemini Planet Imager, highlighting the importance of environmental control for optimal AO performance.

Contribution

It provides the first analysis of dome turbulence effects on AO performance, emphasizing the impact of temperature gradients on image contrast and wavefront error.

Findings

Performance correlates with temperature difference between primary mirror and outside air.

Temperature control strategies influence AO system effectiveness.

Environmental factors are critical for high-contrast exoplanet imaging.

Abstract

The Gemini Planet Imager (GPI) is a near-infrared instrument that uses Adaptive Optics (AO), a coronagraph, and advanced data processing techniques to achieve very high contrast images of exoplanets. The GPI Exoplanet Survey (GPIES) is a 600 stars campaign aiming at detecting and characterizing young, massive and self-luminous exoplanets at large orbital distances >5 au. Science observations are taken simultaneously with environmental data revealing information about the turbulence in the telescope environment as well as limitations of GPI's AO system. Previous work has shown that the timescale of the turbulence, Tau0, is a strong predictor of AO performance, however an analysis of the dome turbulence on AO performance has not been done before. Here, we study correlations between image contrast and residual wavefront error (WFE) with temperature measurements from multiple locations inside and outside the dome. Our analysis revealed GPI's performance is most correlated with the temperature difference between the primary mirror of the telescope and the outside air. We also assess the impact of the current temperature control and ventilation strategy at Gemini South (GS).