ABORAS: polarimetric, 10cm/s RV observations of the Sun as a star

TL;DR

ABORAS is a dual-beam polarimeter designed to measure solar radial velocity variations and magnetic fields with high precision, aiding stellar variability studies and exoplanet detection benchmarks.

Contribution

It introduces a new polarimetric instrument capable of detecting 10cm/s RV variations and sub-Gauss magnetic fields in the Sun as a star.

Findings

Achieves 10cm/s RV measurement precision.

Detects magnetic fields below 1 Gauss.

Serves as a benchmark for Earth-like exoplanet detection.

Abstract

We present a description of A dual-Beam pOlarimetric Robotic Aperture for the Sun (ABORAS), to serve as a Solar input with a dedicated Stokes V polarimeter for the HARPS3 high-resolution spectrograph. ABORAS has three main science drivers: trying to understand the physics behind stellar variability, tracking the long-term stability of HARPS3, and serve as a benchmark for Earth-sized exoplanet detection with HARPS3 by injecting an Earth RV signal into the data. By design, ABORAS will (together with the HARPS3 instrument) be able to measure 10cm/s variations in RV of the integrated Solar disk and detect integrated magnetic field levels at sub 1 Gauss level through circularly polarized light.