TY - JOUR
T1 - Resolving faint structures in the debris disk around TWA 7
T2 - Tentative detections of an outer belt, a spiral arm, and a dusty cloud
AU - Olofsson, J.
AU - Van Holstein, R. G.
AU - Boccaletti, A.
AU - Janson, M.
AU - Thébault, P.
AU - Gratton, R.
AU - Lazzoni, C.
AU - Kral, Q.
AU - Bayo, A.
AU - Canovas, H.
AU - Caceres, C.
AU - Ginski, C.
AU - Pinte, C.
AU - Asensio-Torres, R.
AU - Chauvin, G.
AU - Desidera, S.
AU - Henning, Th
AU - Langlois, M.
AU - Milli, J.
AU - Schlieder, J. E.
AU - Schreiber, M. R.
AU - Augereau, J. C.
AU - Bonnefoy, M.
AU - Buenzli, E.
AU - Brandner, W.
AU - Durkan, S.
AU - Engler, N.
AU - Feldt, M.
AU - Godoy, N.
AU - Grady, C.
AU - Hagelberg, J.
AU - Lagrange, A. M.
AU - Lannier, J.
AU - Ligi, R.
AU - Maire, A. L.
AU - Mawet, D.
AU - Ménard, F.
AU - Mesa, D.
AU - Mouillet, D.
AU - Peretti, S.
AU - Perrot, C.
AU - Salter, G.
AU - Schmidt, T.
AU - Sissa, E.
AU - Thalmann, C.
AU - Vigan, A.
AU - Abe, L.
AU - Feautrier, P.
AU - Le Mignant, D.
AU - Moulin, T.
AU - Pavlov, A.
AU - Rabou, P.
AU - Rousset, G.
AU - Roux, A.
N1 - Funding Information:
Acknowledgements. We would like to thank the anonymous referee for the valuable feedback we received, especially regarding the uncertainties derived for the best-fitting model. This research has made use of the SIMBAD database (operated at CDS, Strasbourg, France) and makes use of VOSA, developed under the Spanish Virtual Observatory project supported from the Spanish MICINN through grant AyA2011-24052. This research made use of Astropy, a community-developed core Python package for Astronomy (Astropy Collaboration 2013), as well as the TOPCAT software (Taylor 2005). SPHERE is an instrument designed and built by a consortium consisting of IPAG (Grenoble, France), MPIA (Heidelberg, Germany), LAM (Marseille, France), LESIA (Paris, France), Laboratoire Lagrange (Nice, France), INAF–Osservatorio di Padova (Italy), Observatoire de Genève (Switzerland), ETH Zurich (Switzerland), NOVA (The Netherlands), ONERA (France) and ASTRON (The Netherlands) in collaboration with ESO. SPHERE was funded by ESO, with additional contributions from CNRS (France), MPIA (Germany), INAF (Italy), FINES (Switzerland) and NOVA (The 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). We also acknowledge financial support from the Programme National de Planétologie (PNP) and the Programme National de Physique Stellaire (PNPS) of CNRS-INSU in France. This work has also been supported by a grant from the French Labex OSUG@2020 (Investissements d’avenir – ANR10 LABX56). The project is supported by CNRS, by the Agence Nationale de la Recherche (ANR-14-CE33-0018). It has also been carried out within the frame of the National Centre for Competence in Research PlanetS supported by the Swiss National Science Foundation (SNSF). MRM, HMS, and SD are pleased to acknowledge this financial support of the SNSF. Finally, this work has made use of the SPHERE Data Centre, jointly operated by OSUG/IPAG (Grenoble), PYTHEAS/LAM/CESAM (Marseille), OCA/Lagrange (Nice) and Observatoire de Paris/LESIA (Paris). We thank P. Delorme and E. Lagadec (SPHERE Data Centre) for their efficient help during the data reduction process. J.O., A.B., M.R.S., C.C., and N.G. acknowledge support from the ICM (Iniciativa Científica Milenio) via the Nucleo Milenio de Formación planetaria grant. J.O acknowledges support from the Universidad de Valparaíso and from Fondecyt (grant 1180395). C.C. acknowledges support from project CONICYT PAI/Concurso Nacional Insercion en la Academia, convocatoria 2015, folio
Funding Information:
79150049. R.A.-T. gratefully acknowledges funding from the Knut and Alice Wallenberg foundation. Q.K. acknowledges funding from STFC via the Institute of Astronomy, Cambridge Consolidated Grant. M.R.S. thanks for support from Fondecyt (grant 1141269). R.G., C.L., S.D., and D.M. acknowledge support from the “Progetti Premiali” funding scheme of the Italian Ministry of Education, University, and Research. This work has been supported by the project PRIN-INAF 2016 The Cradle of Life – GENESIS – SKA (General Conditions in Early Planetary Systems for the rise of life with SKA). N.G. acknowledges grant support from project CONICYT-PFCHA/Doctorado Nacional/2017 folio 21170650. F.M, C.P., and M.L. acknowledge funding from ANR of France under contract number ANR-16-CE31-0013. C.P. acknowledges funding from the Australian Research Council (ARC) under the Future Fellowship number FT17010004.
Publisher Copyright:
© 2018 ESO.
PY - 2018/9/26
Y1 - 2018/9/26
N2 - Context. Debris disks are the intrinsic by-products of the star and planet formation processes. Most likely due to instrumental limitations and their natural faintness, little is known about debris disks around low mass stars, especially when it comes to spatially resolved observations. Aims. We present new VLT/SPHERE IRDIS dual-polarization imaging (DPI) observations in which we detect the dust ring around the M2 spectral type star TWA 7. Combined with additional angular differential imaging observations we aim at a fine characterization of the debris disk and setting constraints on the presence of low-mass planets. Methods. We modeled the SPHERE DPI observations and constrain the location of the small dust grains, as well as the spectral energy distribution of the debris disk, using the results inferred from the observations, and performed simple N-body simulations. Results. We find that the dust density distribution peaks at ∼0.72′′ (25 au), with a very shallow outer power-law slope, and that the disk has an inclination of ∼13° with a position angle of ∼91° east of north. We also report low signal-to-noise ratio detections of an outer belt at a distance of ∼1.5′′ (∼52 au) from the star, of a spiral arm in the southern side of the star, and of a possible dusty clump at 0.11′′. These findings seem to persist over timescales of at least a year. Using the intensity images, we do not detect any planets in the close vicinity of the star, but the sensitivity reaches Jovian planet mass upper limits. We find that the SED is best reproduced with an inner disk at ∼0.2′′ (∼7 au) and another belt at 0.72′′ (25 au). Conclusions. We report the detections of several unexpected features in the disk around TWA 7. A yet undetected 100M· planet with a semi-major axis at 20-30 au could possibly explain the outer belt as well as the spiral arm. We conclude that stellar winds are unlikely to be responsible for the spiral arm.
AB - Context. Debris disks are the intrinsic by-products of the star and planet formation processes. Most likely due to instrumental limitations and their natural faintness, little is known about debris disks around low mass stars, especially when it comes to spatially resolved observations. Aims. We present new VLT/SPHERE IRDIS dual-polarization imaging (DPI) observations in which we detect the dust ring around the M2 spectral type star TWA 7. Combined with additional angular differential imaging observations we aim at a fine characterization of the debris disk and setting constraints on the presence of low-mass planets. Methods. We modeled the SPHERE DPI observations and constrain the location of the small dust grains, as well as the spectral energy distribution of the debris disk, using the results inferred from the observations, and performed simple N-body simulations. Results. We find that the dust density distribution peaks at ∼0.72′′ (25 au), with a very shallow outer power-law slope, and that the disk has an inclination of ∼13° with a position angle of ∼91° east of north. We also report low signal-to-noise ratio detections of an outer belt at a distance of ∼1.5′′ (∼52 au) from the star, of a spiral arm in the southern side of the star, and of a possible dusty clump at 0.11′′. These findings seem to persist over timescales of at least a year. Using the intensity images, we do not detect any planets in the close vicinity of the star, but the sensitivity reaches Jovian planet mass upper limits. We find that the SED is best reproduced with an inner disk at ∼0.2′′ (∼7 au) and another belt at 0.72′′ (25 au). Conclusions. We report the detections of several unexpected features in the disk around TWA 7. A yet undetected 100M· planet with a semi-major axis at 20-30 au could possibly explain the outer belt as well as the spiral arm. We conclude that stellar winds are unlikely to be responsible for the spiral arm.
KW - Circumstellar matter
KW - Instrumentation: high angular resolution
KW - Instrumentation: polarimeters
UR - http://www.scopus.com/inward/record.url?scp=85048038081&partnerID=8YFLogxK
U2 - 10.1051/0004-6361/201832583
DO - 10.1051/0004-6361/201832583
M3 - Article
AN - SCOPUS:85048038081
SN - 0004-6361
VL - 617
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A109
ER -