Affordable spectroscopy for 1m-class telescopes

TL;DR

This paper demonstrates that affordable, small-aperture telescopes equipped with commercially available spectrographs can achieve useful Doppler velocity measurements, enabling cost-effective exoplanet follow-up observations.

Contribution

The study shows that small telescopes with off-the-shelf spectrographs can reliably measure stellar radial velocities, expanding Doppler exoplanet detection capabilities to smaller, less expensive instruments.

Findings

Achieved velocity precision of 50-100 m/s with small telescopes.

Validated the use of a commercial echelle spectrograph for exoplanet follow-up.

Demonstrated cost-effective radial velocity measurements with sub-meter telescopes.

Abstract

Doppler observations of exoplanet systems have been a very expensive technique, mainly due to the high costs of high-resolution stable spectrographs. Recent advances in instrumentation enable affordable Doppler planet detections with surprisingly small optical telescopes. We investigate the possibility of measuring Doppler reflex motion of planet hosting stars with small-aperture telescopes that have traditionally been neglected for this kind of studies. After thoroughly testing the recently developed and commercially available Shelyak eShel echelle spectrograph, we demonstrated that it is routinely possible to achieve velocity precision at the $100 \mathrm{m\,s}^{-1}$ level, reaching down to $\pm 50~\mathrm{m\,s}^{-1}$ for the best cases. We describe our off-the-shelf instrumentation, including a new 0.5m RC telescope at the Gothard Astrophysical Observatory of Lor\'and E\"otv\"os University equipped with an intermediate resolution fiber-fed echelle spectrograph. We present some follow-up radial velocity measurements of planet hosting stars and point out that updating the orbital solution of Doppler-planets is a very important task that can be fulfilled with sub-meter sized optical telescopes without requesting very expensive telescope times on 2--4~m (or larger) class telescopes.