Publication: The CARMENES search for exoplanets around M dwarfs Spectroscopic orbits of nine M-dwarf multiple systems, including two triples, two brown dwarf candidates, and one close M-dwarf-white dwarf binary
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Context. M dwarfs are ideal targets for the search of Earth-size planets in the habitable zone using the radial velocity method, attracting the attention of many ongoing surveys. As a by-product of these surveys, new multiple stellar systems are also found. This is he case also for the CARMENES survey, from which nine new double-line spectroscopic binary systems have already been announced. Aims. Throughout the five years of the survey, the accumulation of new observations has resulted in the detection of several new multiple stellar systems with long periods and low radial-velocity amplitudes. Here, we newly characterise the spectroscopic orbits and constrain the masses of eight systems and update the properties of a system that we reported earlier. Methods. We derive the radial velocities of the stars using two-dimensional cross correlation techniques and template matching. The measurements are modelled to determine the orbital parameters of the systems. We combine CARMENES pectroscopic observations with archival high-resolution spectra from other instruments to increase the time-span of the observations and improve our analysis. When available, we also added archival photometric, astrometric, and adaptive optics imaging data to constrain the rotation periods and absolute masses of the components. Results. We determine the spectroscopic orbits of nine multiple systems, eight of which are presented for the first time. The sample is composed of five single-line binaries, two double-line binaries, and two triple-line spectroscopic triple systems. The companions of two of the single-line binaries, GJ 3626 and GJ 912, have minimum masses below the stellar boundary and, thus, could be brown dwarfs. We find a new white dwarf in a close binary orbit around the M star GJ 207.1, located at a distance of 15.79 pc. From a global fit to radial velocities and astrometric measurements, we are able to determine the absolute masses of the components of GJ 282 C, which is one of the youngest systems with measured dynamical masses.
© ESO 2021. Artículo firmado por 36 autores. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Junta de Andalucía and the Instituto de Astrofísica de Andalucía (CSIC). CARMENES is funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de Investigaciones Científicas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium (Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Andalucía, Landessternwarte Königstuhl, Institut de Ciències de l’Espai, Insitut für Astrophysik Göttingen, Universidad Complutense de Madrid, Thüringer Landessternwarte Tautenburg, Instituto de Astroísica de Canarias, Hamburger Sternwarte, Centro de Astrobiología and Centro Astronómico Hispano-Alemán), with additional contributions by the Spanish Ministry of Economy, the German Science Foundation through the Major Research Instrumentation Programme and DFG Research Unit FOR2544 “Blue Planets around Red Stars”, the Klaus Tschira Stiftung, the states of Baden-Württemberg and Niedersachsen, and by the Junta de Andalucía. Based on data from the CARMENES data archive at CAB (INTA-CSIC). Based on observations made with the 0.9-m telescope at the Sierra Nevada Observatory (Granada, Spain), operated by the Instituto de Astrofísica de Andalucía, the 0.8-m Joan Oró telescope (TJO) of the Montsec Astronomical Observatory (Lleida, Spain), owned by the Generalitat de Catalunya and operated by the Institut d’Estudis Espacials de Catalunya (IEEC), on observations collected at the European Southern Observatory under ESO programs 098.C-0739(A) and 192.C-0224(C) (P.I. A. M. Lagrange), 180.C-0886(A) and 183.C-0437(A) (P.I. X. Bonfils), 074.D-0016(A) (P.I. D. Montes), 078.A- 9048(A) (P.I. J. Setiawan), 085.A-9027(A) (P.I. R. Gredel), 090.A-9003(A) and 091.A-9004(A) (P.I. R. Mundt), 173.C-0606(C) (P.I. M. Kürster), 096.D-0818(A) (P.I. K. Ward-Duong), 094.C-0625(A) and 097.C-0972(A) (P.I. J. H. Gi-rard), and 081.A-9005(A), 081.A-9024(A), 083.A-9002(A), 083.A-9012(A,B),085.A-9009(A), and 086.A-9016(A) (P.I. M. Zechmeister). This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. IRAF was distributed by the National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation. We acknowledge financial support from the Spanish Agencia Estatal de Investigación of the Ministerio de Ciencia e Innovación (AEI-MCINN) and the European FEDER/ERF funds through projects PGC2018-098153-B-C33, PID2019-109522GB-C51/52/53/54, PID2019-107061GB-C64, ESP2017-87143-R, and the Centre of Excellence “Severo Ochoa” and “María de Maeztu” awards to the Instituto de Astrofísica de Canarias (SEV-2015-0548), Instituto de Astrofísica de Andalucía (SEV-2017-0709), and Centro de Astrobiología (MDM-2017-0737), the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya and the Agència de Gestió d’Ajuts Universitaris i de Recerca of the Generalitat de Catalunya, with additional unding from the European FEDER/ERF funds, L’FSE inverteixen el teu futur, and from the Generalitat de Catalunya/CERCA programme.