CORALIE radial-velocity search for companions around evolved stars (CASCADES): IV. New planetary systems around HD 87816, HD 94890, and HD 102888 and an update on HD 121056

Article Article scientifique Article CORALIE radial-velocity search for companions around evolved stars (CASCADES): IV. New planetary systems around HD 87816, HD 94890, and HD 102888 and an update on HD 121056 eng 2025-07-01 author Fontanet Emile Sylvain Ulysse 0000-0002-0215-4551 838478 Département d'astronomie (ASTRO) author Udry Stéphane 0000-0001-7576-6236 23409 Département d'astronomie (ASTRO) author Segransan Damien 0000-0003-2355-8034 134301 Département d'astronomie (ASTRO) author Figueira Pedro Ricardo 0000-0001-8504-283X 637397 Département d'astronomie (ASTRO) author Acevedo Barroso J. A. 0000-0002-9654-1711 author Akinsanmi Tunde 972418 Département d'astronomie (ASTRO) author Attia Mara 0000-0002-7971-7439 928571 author Battley Matthew 0000-0002-1357-9774 402414 author Bhatnagar Siddharth 0000-0001-9178-168X 940400 Département d'astronomie (ASTRO) author Bugatti Maddalena 930785 Département d'astronomie (ASTRO) author Carteret Yann Nicolas Philippe 876207 Département d'astronomie (ASTRO) author Chakraborty Hritam 0000-0002-5177-1898 973565 Département d'astronomie (ASTRO) author Deline Adrien 797061 Département d'astronomie (ASTRO) author Farret Casper 0000-0001-9688-9294 972498 Département d'astronomie (ASTRO) author Frensch Yolanda Gerardina Cécile 0000-0003-4009-0330 975671 Département d'astronomie (ASTRO) author Houelle Mathilde 402452 Département d'astronomie (ASTRO) author Lavie Baptiste 0000-0001-8884-9276 861546 Département d'astronomie (ASTRO) author Lovis Christophe 0000-0001-7120-5837 134919 Département d'astronomie (ASTRO) author Mayor Michel 0000-0002-9352-5935 24719 Administration de la faculté des sciences (SIAD) author Nigioni Arianna 0009-0004-5882-6574 407973 Département d'astronomie (ASTRO) author Ottoni Gaël 0000-0001-9305-9631 744952 author Pepe Francesco Alfonso 0000-0002-9815-773X 124203 Département d'astronomie (ASTRO) author Petit Dominique 974147 author Shinde Muskan 400610 Département d'astronomie (ASTRO) author Santos N. C. 0000-0003-4422-2919 author Tavella Sara 0009-0005-0003-2429 406251 Département d'astronomie (ASTRO) author Unger Nicolas 0000-0003-3993-7127 915191 author Viviani G. 0009-0001-6201-2897 A38 10.1051/0004-6361/202554137 0004-6361 https://www.aanda.org/10.1051/0004-6361/202554137 Context. With around 200 detections of exoplanets around giant stars to date, our knowledge of the population of exoplanets orbiting evolved hosts more massive than the Sun remains limited. The CORALIE radial-velocity search for companions around evolved stars (CASCADES) was launched in 2006 with the aim of improving our understanding of the demographics of exoplanets around intermediate-mass stars, by studying them once they have evolved off the main sequence. Aims. We intend to refine the current sample of known exoplanets orbiting intermediate-mass (1.5–5 M⊙) giant stars of spectral types G and early K. We searched for exoplanets orbiting the four stars HD 87816, HD 94890, HD 102888, and HD 121056. Methods. We used data obtained with the CORALIE spectrograph, mounted on the Leonhard Euler Swiss telescope located at La Silla Observatory in Chile. We gathered high-precision radial-velocity measurements over more than ten years for each of the aforementioned targets. We started by performing a search for periodic signals in the radial-velocity time series of the four targets by using periodograms. Following this, we fit for a Keplerian model using the significant peak with the highest power of the periodogram as the starting guess for the period. We then subtracted this model and repeated the procedure iteratively on the residuals until no significant peaks were found. Finally, to explore the posterior distribution of our models, the final solution was determined using a Markov chain Monte Carlo approach. Results. We report the discovery of five new massive planets around HD 87816, HD 94890, and HD 102888 as well as the presence of a distant, potentially substellar, companion around HD 102888. We confirm the presence of a previously announced exoplanet orbiting the HD 121056 multi-object system with a period of 89 days and propose an update to the period of the outer companion. Planets and satellites: detection Stars: individual: HD 87816 Stars: individual: HD 94890 Stars: individual: HD 102888 Stars: individual: HD 121056 Dewey 520 Swiss National Science Foundation Extrasolar planets, detection and characterisation 205010 CH Projects Swiss National Science Foundation NCCR PlanetS: Origin, evolution and characterisation of planets (phase II) 182901 CH Programmes Swiss National Science Foundation NCCR PlanetS: Origin, evolution and characterisation of planets (phase III) 205606 CH Programmes European Commission FInding ExoeaRths: tackling the ChallengEs of stellar activity 101052347 FIERCE EU HE Fundação para a Ciência e a Tecnologia, I.P. Institute of Astrophysics and Space Sciences UIDB/04434/2020 IA PT 6817 - DCRRNI ID Fundação para a Ciência e a Tecnologia, I.P. Institute of Astrophysics and Space Sciences UIDP/04434/2020 IA PT 6817 - DCRRNI ID Swiss National Science Foundation Planet Formation in Binaries: linking theory and observations 208945 CH Careers 26 Département d'astronomie 12 false Astronomy & astrophysics 699 ac824719-7aad-4605-9301-5c1434e97fa1 Article (Published version) Public Article_scientifique_from_crossref.pdf 7078214 application/pdf CC BY-4.0 d7d5788d86f85071e655cfd370177310f1a225e8f97ff15da65f425d269dac8f openAccess Faculté des sciences / Département d'astronomie

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