2021/08/23 by N. Unger, D. Ségransan, D. Queloz +25 · 15 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Exoplanet #Gamma-ray bursts and supernovae #Physics #Planet #Planetary system #Radial velocity #Stars #Stellar, planetary, and galactic studies #astro-ph.EP
paper · pdf · doi:10.1051/0004-6361/202141351
published in Astronomy and Astrophysics 654, A104 (EDP Sciences) · 19 pages, 17 figures
arxiv created 2021/08/23 · openalex publication_date 2021/10/01 · arxiv updated 2021/10/20 · openalex created_date 2021/10/25 · openalex updated_date 2026/08/05
Context. We present precise radial-velocity measurements of five solar-type stars observed with the HARPS Echelle spectrograph mounted on the 3.6-m telescope in La Silla (ESO, Chile). With a time span of more than 10 yr and a fairly dense sampling, the survey is sensitive to low mass planets down to super-Earths on orbital periods up to 100 days. Aims. Our goal was to search for planetary companions around the stars HD 39194, HD 93385, HD 96700, HD 154088, and HD 189567 and use Bayesian model comparison to make an informed choice on the number of planets present in the systems based on the radial velocity observations. These findings will contribute to the pool of known exoplanets and better constrain their orbital parameters. Methods. A first analysis was performed using the Data & Analysis Center for Exoplanets online tools to assess the activity level of the star and the potential planetary content of each system. We then used Bayesian model comparison on all targets to get a robust estimate on the number of planets per star. We did this using the nested sampling algorithm P OLY C HORD . For some targets, we also compared different noise models to disentangle planetary signatures from stellar activity. Lastly, we ran an efficient Markov chain Monte Carlo algorithm for each target to get reliable estimates for the planets’ orbital parameters. Results. We identify 12 planets within several multiplanet systems. These planets are all in the super-Earth and sub-Neptune mass regime with minimum masses ranging between 4 and 13 M ⊕ and orbital periods between 5 and 103 days. Three of these planets are new, namely HD 93385 b, HD 96700 c, and HD 189567 c.