The SOPHIE search for northern extrasolar planets VIII. A warm Neptune orbiting HD164595

TL;DR

This paper reports the detection of a warm Neptune exoplanet orbiting HD164595 using high-precision radial velocity measurements, contributing to understanding low-mass planet populations around bright stars.

Contribution

It presents the discovery of a new warm Neptune around HD164595 with improved radial velocity techniques and updates the parameters of another planetary system, enhancing exoplanet statistical models.

Findings

Detected a warm Neptune with 16.1 ± 2.7 Mearth mass.

Achieved 2 m/s radial velocity precision with SOPHIE spectrograph.

Revised parameters of the HD190360 planetary system.

Abstract

High-precision radial velocity surveys explore the population of low-mass exoplanets orbiting bright stars. This allows accurately deriving their orbital parameters such as their occurrence rate and the statistical distribution of their properties. Based on this, models of planetary formation and evolution can be constrained. The SOPHIE spectrograph has been continuously improved in past years, and thanks to an appropriate correction of systematic instrumental drift, it is now reaching 2 m/s precision in radial velocity measurements on all timescales. As part of a dedicated radial velocity survey devoted to search for low-mass planets around a sample of 190 bright solar-type stars in the northern hemisphere, we report the detection of a warm Neptune with a minimum mass of 16.1 +- 2.7 Mearth orbiting the solar analog HD164595 in 40 +- 0.24 days . We also revised the parameters of the multiplanetary system around HD190360. We discuss this new detection in the context of the upcoming space mission CHEOPS, which is devoted to a transit search of bright stars harboring known exoplanets.