The Replicable High-resolution Exoplanet and Asteroseismology (RHEA) spectrograph

Abstract

The current limitations associated with detecting exoplanets using Radial Velocity (RV) measurements include temperature stability of spectrographs and efficient fibre scrambling in the quest for sub metre/ sec precision. However, an astrophysical fundamental limitation is also present, in the form of noise from stellar activity. This is particularly true for giant stars, where the amplitude of pulsations is comparable with RV signals from hot-Jupiters. Long-baseline RV measurements are required to measure the intrinsic pulsations of the host star and de- correlate them to look for the planetary signals. This process uses these data for asteroseismological analysis, which also provides improved precision on the stellar mass and density. This is impractical using large telescopes, but possible to do on bright stars with 0.3-1m class telescopes. This poster presents the current status of the Replicable High-Resolution Exoplanets and Asteroseismology (RHEA) spectrograph, a compact single-mode fibre-fed spectrograph being developed at Macquarie University. It will serve the basis of a series of cheap spectrographs, composed of many "off the shelf" items, to be deployed on small telescopes for exoplanet and asteroseismological studies of giant stars, providing accessible technology to address this exciting problem.