Precise radial velocities with ESPRESSO: pushing the limit to 10 cm/s

Описание: Precise radial velocities with ESPRESSO: pushing the limit to 10 cm/s

13/01/2026 - 12:30
Pedro Figueira
IAA-CSIC


The ESPRESSO spectrograph, mounted on the VLT, was designed to achieve a long-term radial velocity (RV) precision of 10 cm/s, enabling the detection of Earth-mass planets within the habitable zones (HZ) of their host stars.

I present results from the instrument’s Guaranteed Time Observations campaign on three low-activity G, K, and M stars. We characterise the precision achievable from the timescales of minutes and dominated by pulsations, to timescales of years as required for HZ planet detection. To achieve this, we employ different RV calculation methods and activity indicators, assessing the limiting factors of both instrumental precision and stellar RV stability. Using a comprehensive analysis, we reach a RV floor level of 40 cm/s over a timescale of several years.

Interestingly, the ESPRESSO data shows no evidence for several previously announced planetary signals; we discuss the population of planets that, while not directly observed, remain consistent with ESPRESSO data.

Finally, we explore the stellar physical phenomena that can be studied to further improve RV precision and enhance our planet detection capabilities. This is key for the future precise RV campaigns as enabled by ESPRESSO and similar instruments.