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Upper limits for mass and radius of objects around Proxima Cen from SPHERE/VLT

Published version
Peer-reviewed

Type

Article

Change log

Authors

Mesa, D 
Zurlo, A 
Milli, J 
Gratton, R 
Desidera, S 

Abstract

The recent discovery of an earth-like planet around Proxima Centauri has drawn much attention to this star and its environment. We performed a series of observations of Proxima Centauri using Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE), the planet-finder instrument installed at the European Southern Observatory (ESO) Very Large Telescope (VLT) UT3, using its near-infrared modules, InfraRed Dual-band Imager and Spectrograph (IRDIS) and IFS. No planet was detected directly, but we set upper limits on the mass up to 7 au by exploiting the AMES-COND models. Our IFS observations reveal that no planet more massive than ∼6–7 MJup can be present within 1 au. The dual-band imaging camera IRDIS also enables us to probe larger separations than other techniques such as radial velocity or astrometry. We obtained mass limits of the order of 4 MJup at separations of 2 au or larger, representing the most stringent mass limits at separations larger than 5 au available at the moment. We also made an attempt to estimate the radius of possible planets around Proxima using the reflected light. Since the residual noise for the observations is dominated by photon noise and thermal background, longer exposures in good observing conditions could improve the achievable contrast limit further.

Description

Keywords

instrumentation: spectrographs, methods: data analysis, techniques: imaging spectroscopy, stars: individual: Proxima Centauri, planetary systems

Journal Title

Monthly Notices of the Royal Astronomical Society

Conference Name

Journal ISSN

1745-3925
1745-3933

Volume Title

466

Publisher

Oxford University Press
Sponsorship
European Research Council (279973)
Science and Technology Facilities Council (ST/N000927/1)
European Commission (226604)
European Commission (312430)
DM, AZ, RG, RUC, SD and ES acknowledge support from the ‘Progetti Premiali’ funding scheme of MIUR. We acknowledge support from the French ANR through the GUEPARD project grant ANR10-BLANC0504-01. QK acknowledges support from the EU through ERC grant number 279973. JH is supported by the GIPSE grant ANR-14-CE33-0018. HA acknowledges financial support by FONDECYT, grant 3150643, and support from the Millennium Science Initiative (Chilean Ministry of Economy) through grant RC130007. SPHERE was funded by ESO, with additional contributions from CNRS (France), MPIA (Germany), INAF (Italy), FINES (Switzerland) and NOVA (Netherlands). SPHERE also received funding from the European Commission Sixth and Seventh Framework Programmes as part of the Optical Infrared Coordination Network for Astronomy (OPTICON) under grant number RII3-Ct-2004-001566 for FP6 (2004-2008), grant number 226604 for FP7 (2009-2012) and grant number 312430 for FP7 (2013-2016). Part of this has been carried out within the frame of the National Centre for Competence in Research Planets supported by the Swiss National Science Foundation. H.M.S. and M.R.M. acknowledge financial support from the SNSF.