Suchergebnisse

We describe the Next Generation Transit Survey (NGTS), which is a ground-based project searching for transiting exoplanets orbiting bright stars. NGTS builds on the legacy of previous surveys, most notably WASP, and is designed to achieve higher photometric precision and hence find smaller planets than have previously been detected from the ground. It also operates in red light,maximizing sensitivity to late K and earlyMdwarf stars. The survey specifications call for photometric precision of 0.1 per cent in red light over an instantaneous field of view of 100 deg2, enabling the detection of Neptune-sized exoplanets around Sun-like stars and super-Earths around M dwarfs. The survey is carried out with a purpose-built facility at Cerro Paranal, Chile, which is the premier site of the European Southern Observatory (ESO). An array of twelve 20 cm f/2.8 telescopes fitted with back-illuminated deep-depletion CCD cameras is used to survey fields intensively at intermediateGalactic latitudes. The instrument is also ideally suited to ground-based photometric follow-up of exoplanet candidates from space telescopes such as TESS, Gaia and PLATO. We present observations that combine precise autoguiding and the superb observing conditions at Paranal to provide routine photometric precision of 0.1 per cent in 1 h for stars with I-band magnitudes brighter than 13. We describe the instrument and data analysis methods as well as the status of the survey, which achieved first light in 2015 and began full-survey operations in 2016. NGTS data will be made publicly available through the ESO archive. ; The capital costs of the NGTS facility were funded by the University of Warwick, the University of Leicester, Queen's University Belfast, the University of Geneva, the Deutsches Zentrum fur Luft- und ¨ Raumfahrt e.V. (DLR; under the 'Großinvestition GI-NGTS'), the University of Cambridge and the UK Science and Technology Facilities Council (STFC; project reference ST/M001962/1). The facility is operated by the consortium institutes with support from STFC (also project ST/M001962/1). We are grateful to ESO for providing access to the Paranal site as well as generous in-kind support. The research leading to these results has received funding from the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement n. 320964 (WDTracer). The contributions at the University of Warwick by PJW, RGW, DLP, FF, DA, BTG and TL have been supported by STFC through consolidated grants ST/L000733/1 and ST/P000495/1. TL was also supported by STFC studentship 1226157. EF is funded by the Qatar National Research Foundation (programme QNRF-NPRP-X-019-1). MNG is supported by STFC studentship 1490409 as well as the Isaac Newton Studentship. JSJ acknowledges support by FONDECYT grant 1161218 and partial support by CATA-Basal (PB06, CONICYT). AJ acknowledges support from FONDECYT project 1171208, BASAL CATA PFB-06, and by the Ministry for the Economy, Development, and Tourism's Programa Iniciativa Cient´ıfica Milenio through grant IC 120009, awarded to the Millennium Institute of Astrophysics (MAS). FF acknowledges support from 'Accordo ASIINAF for PLATO' No. 2015-019-R.0 July 29, 2015.

Context. M dwarfs are ideal targets for the search of Earth-size planets in the habitable zone using the radial velocity method, and are attracting the attention of many ongoing surveys. One of the expected results of these surveys is that new multiple-star systems have also been found. This is the case also for the CARMENES survey, thanks to 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 had reported earlier. Methods. We derived the radial velocities of the stars using two-dimensional cross-correlation techniques and template matching. The measurements were modelled to determine the orbital parameters of the systems. We combined CARMENES spectroscopic 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 determined 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 found 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 were 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. ; Based on observations collected at the Centro Astronomico Hispano Aleman (CAHA) at Calar Alto, operated jointly by the Junta de Andalucia and the Instituto de Astrofisica de Andalucia (CSIC). CARMENES is funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de Investigaciones Cientificas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium (Max-Planck-Institut fur Astronomie, Instituto de Astrofisica de Andalucia, Landessternwarte Konigstuhl, Institut de Ciencies de l'Espai, Insitut fur Astrophysik Gottingen, Universidad Complutense de Madrid, Thuringer Landessternwarte Tautenburg, Instituto de Astroisica de Canarias, Hamburger Sternwarte, Centro de Astrobiologia and Centro Astronomico Hispano-Aleman), 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-Wurttemberg and Niedersachsen, and by the Junta de Andalucia. 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 Astrofisica de Andalucia, the 0.8-m Joan Oro 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.D0016(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. Kurster), 096.D-0818(A) (P.I. K. Ward-Duong), 094.C-0625(A) and 097.C-0972(A) (P.I. J. H. Girard), 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 Investigacion of the Ministerio de Ciencia e Innovacion (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 "Maria de Maeztu" awards to the Instituto de Astrofisica de Canarias (SEV-2015-0548), Instituto de Astrofisica de Andalucia (SEV2017-0709), and Centro de Astrobiologia (MDM-2017-0737), the Secretaria d'Universitats i Recerca del Departament d'Empresa i Coneixement de la Generalitat de Catalunya and the Agencia de Gestio d'Ajuts Universitaris i de Recerca of the Generalitat de Catalunya, with additional funding from the European FEDER/ERF funds, L'FSE inverteix en el teu futur, and from the Generalitat de Catalunya/CERCA programme. ; Peer reviewed