RT Journal Article T1 The CARMENES search for exoplanets around M dwarfs A Neptune-mass planet traversing the habitable zone around HD 180617 A1 Kaminski, A. A1 Trifonov, T. A1 Caballero, J. A. A1 Quirrenbach, A. A1 Ribas, I. A1 Reiners, A. A1 Amado, P. J. A1 Zechmeister, M. A1 Dreizler, S. A1 Perger, M. A1 Tal-Or, L. A1 Bonfils, X. A1 Mayor, M. A1 Astudillo Defru, N. A1 Bauer, F. F. A1 Béjar, V. J. S. A1 Cifuentes, C. A1 Colomé, J. A1 Cortés Contreras, Miriam A1 Delfosse, X. A1 Díez Alonso, E. A1 Forveille, T. A1 Guenther, E. W. A1 Hatzes, A. P. A1 Henning, Th. A1 Jeffers, S. V. A1 Kürster, M. A1 Lafarga, M. A1 Luque, R. A1 Mandel, H. A1 Montes Gutiérrez, David A1 Morales, J. C. A1 Passegger, V. M. A1 Pedraz, S. A1 Reffert, S. A1 Sadegi, S. A1 Schweitzer, W. A1 Seifert, W. A1 Stahl, O. A1 Udry, S. AB Despite their activity, low-mass stars are of particular importance for the search of exoplanets by the means of Doppler spectroscopy, as planets with lower masses become detectable. We report on the discovery of a planetary companion around HD 180617, a bright (J = 5.58 mag), low-mass (M = 0.45 M-circle dot) star of spectral type M2.5 V. The star, located at a distance of 5.9 pc, is the primary of the high proper motion binary system containing vB 10, a star with one of the lowest masses known in most of the twentieth century. Our analysis is based on new radial velocity (RV) measurements made at red-optical wavelengths provided by the high-precision spectrograph CARMENES, which was designed to carry out a survey for Earth-like planets around M dwarfs. The available CARMENES data are augmented by archival Doppler measurements from HIRES and HARPS. Altogether, the RVs span more than 16 yr. The modeling of the RV variations, with a semi-amplitude of K = 2.85(-0.25)(+0.16)m s(-1), yields a Neptune-like planet with a minimum mass of 12.2(1.4)(+1.0) M-circle plus on a 105.90(-0.10)(+0.09) d circumprimary orbit, which is partly located in the host star's habitable zone. The analysis of time series of common activity indicators does not show any dependence on the detected RV signal. The discovery of HD 180617 b not only adds information to a currently hardly filled region of the mass-period diagram of exoplanets around M dwarfs, but the investigated system becomes the third known binary consisting of M dwarfs and hosting an exoplanet in an S-type configuration. Its proximity makes it an attractive candidate for future studies. PB EDP Sciences S A SN 1432-0746 YR 2018 FD 2018-10-17 LK https://hdl.handle.net/20.500.14352/12944 UL https://hdl.handle.net/20.500.14352/12944 LA eng NO Kaminski, A., Trifonov, T., Caballero, J. A. et al. «The CARMENES Search for Exoplanets around M Dwarfs - A Neptune-Mass Planet Traversing the Habitable Zone around HD 180617». Astronomy & Astrophysics, vol. 618, octubre de 2018, p. A115. www.aanda.org, https://doi.org/10.1051/0004-6361/201833354. NO German Max-Planck-Gesellschaft NO Consejo Superior de Investigaciones Científicas (España) NO Fondo Europeo de Desarrollo Regional NO Max-Planck-Institut für Astronomie NO Instituto de Astrofísica de Andalucía NO Landessternwarte Königstuhl NO Institut de Ciències de l’Espai NO Insitut für Astrophysik Göttingen NO Universidad Complutense de Madrid NO Thüringer Landessternwarte Tautenburg NO Instituto de Astrofísica de Canarias NO Hamburger Sternwarte NO Centro de Astrobiología and Centro Astronómico Hispano-Alemán NO Ministerio de Ciencia, Innovación y Universidades (España) NO German Science Foundation through the Major Research Instrumentation Programme NO DFG Research Unit FOR2544 “Blue Planets around Red Stars” NO Klaus Tschira Stiftung NO State of Baden-Württemberg NO State of Niedersachsen NO Junta de Andalucía NO Fondo Nacional de Desarrollo Científico y Tecnológico NO W. M. Keck Foundation DS Docta Complutense RD 8 jun 2025