CHARA/SPICA: a 6-telescope visible instrument for the CHARA Array

TL;DR

The paper introduces CHARA/SPICA, a six-telescope visible-light instrument for the CHARA Array, designed for high-resolution stellar observations, a large star survey, and improved surface-brightness relations.

Contribution

It details the design, science goals, and initial performance of the new CHARA/SPICA instrument for stellar parameter measurements.

Findings

Achieved initial performance during commissioning

Enabled high angular resolution observations in the 600-900 nm range

Facilitated a large survey of stars across the Hertzsprung-Russell diagram

Abstract

With a possible angular resolution down to 0.1-0.2 millisecond of arc using the 330 m baselines and the access to the 600-900 nm spectral domain, the CHARA Array is ideally configured for focusing on precise and accurate fundamental parameters of stars. CHARA/SPICA (Stellar Parameters and Images with a Cophased Array) aims at performing a large survey of stars all over the Hertzsprung-Russell diagram. This survey will also study the effects of the different kinds of variability and surface structure on the reliability of the extracted fundamental parameters. New surface-brightness-colour relations will be extracted from this survey, for general purposes on distance determination and the characterization of faint stars. SPICA is made of a visible 6T fibered instrument and of a near-infrared fringe sensor. In this paper, we detail the science program and the main characteristics of SPICA-VIS. We present finally the initial performance obtained during the commissioning.