Prototyping coronagraphs for exoplanet characterization with SPHERE

TL;DR

This paper discusses the development and testing of two types of coronagraph prototypes for the SPHERE instrument, aimed at improving exoplanet detection by reducing starlight interference.

Contribution

It introduces and evaluates two coronagraph prototypes, validating their manufacturing technology for enhanced exoplanet imaging with SPHERE.

Findings

Contrast measurements meet technical specifications

Sensitivity analysis confirms prototype effectiveness

Validation supports future exoplanet characterization efforts

Abstract

The detection and characterization of extrasolar planets with SPHERE (Spectro Polarimetric High contrast Exoplanet REsearch) is challenging and in particular relies on the ability of a coronagraph to attenuate the diffracted starlight. SPHERE includes 3 instruments, 2 of which can be operated simultaneously in the near IR from 0.95 to 1.8 microns. This requirements is extremely critical for coronagraphy. This paper briefly introduces the concepts of 2 coronagraphs, the Half-Wave Plate Four Quadrant Phase Masks and the Apodized Pupil Lyot Coronagraph, prototyped within the SPHERE consortium by LESIA (Observatory of Paris) and FIZEAU (University of Nice) respectively. Then, we present the measurements of contrast and sensitivity analysis. The comparison with technical specifications allows to validate the technology for manufacturing these coronagraphs.