A&A 575, A119 (2015) Astronomy DOI: 10.1051/0004-6361/201424253 & c ESO 2015 Astrophysics The HARPS search for southern extra-solar planets XXXVI. Planetary systems and stellar activity of the M dwarfs GJ 3293, GJ 3341, and GJ 3543?;?? N. Astudillo-Defru1;2, X. Bonfils1;2, X. Delfosse1;2, D. Ségransan3, T. Forveille1;2, F. Bouchy3;4, M. Gillon5, C. Lovis3, M. Mayor3, V. Neves6, F. Pepe3, C. Perrier1;2, D. Queloz3;7, P. Rojo8, N. C. Santos9;10, and S. Udry3 1 Université Grenoble Alpes, IPAG, 38000 Grenoble, France e-mail:
[email protected] 2 CNRS, IPAG, 38000 Grenoble, France 3 Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland 4 Laboratoire d’Astrophysique de Marseille, UMR 6110 CNRS, Université de Provence, 38 rue Frédéric Joliot-Curie, 13388 Marseille Cedex 13, France 5 Institut d’Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août 17, Bat. B5C, 4000 Liège, Belgium 6 Departamento de Física, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN, Brazil 7 Cavendish Laboratory, J J Thomson Avenue, Cambridge, CB3 0HE, UK 8 Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile 9 Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto, Portugal 10 Departamento de Física e Astronomia, Faculdade de Ciências, Universidade do Porto, Portugal Received 22 May 2014 / Accepted 25 November 2014 ABSTRACT Context. Planetary companions of a fixed mass induce reflex motions with a larger amplitude around lower-mass stars, which adds to making M dwarfs excellent targets for extra-solar planet searches.