Work

The RoPES project with HARPS and HARPS-N

Year: 2026

Type: article

Abstract: Context . The development of refined instruments and techniques for a detailed analysis of the radial velocities (RVs) of stars other than the Sun allows the presence of planetary signals of amplitude below 1 m s −1 to be investigated. Long-term RV surveys allow the detection of Earth-like and super-Earth-like planets in the habitable zones of Sun-like stars, prime targets for future missions for the atmospheric characterization of exoplanets. Aims . We present the analysis of the nearby G8 V-type star HD 161098 ( V = 7.68 mag, d = 29.75 pc). We searched for terrestrial planets in the habitable zone. Methods . We combined historical datasets with new data collected in an ongoing blind search program with HARPS, HARPS-N, and ESPRESSO. We utilized recently developed tools to extract RVs and to deal with the analysis of stellar activity. We performed a joint analysis of RVs and activity indicators to separate the planetary signals from those related to activity. Results . We detected two sub-m s −1 signals that we claim as candidate planets. We are not able to confirm their nature with certainty. Candidate HD 161098 b has an orbital period of 72.578 −0.060 +0.059 d and a minimum mass of 3.63 ± 0.59 M ⊕ . HD 161098 c has an orbital period of 682.5 −9.9 +9.5 d and a minimum mass of 7.8 −1.4 +1.5 M ⊕ . If confirmed, candidate HD 161098 c would reside in the optimistic habitable zone of the star. We find a magnetic cycle of 4090 −130 +140 d period and a rotation period of 28.22 −0.35 +0.30 d. Our analysis sets the stage for future observing campaigns of the star, finalized for the confirmation of our results. Conclusions . We are entering the sub-m s −1 era at long orbital periods with a combination of stellar activity treatment and long-term campaigns.

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/202659109