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Very deep images of the innermost regions of the β Pictoris debris disc at L′

Milli, J. and Lagrange, A.-M. and Mawet, D. and Absil, O. and Augereau, J.-C. and Mouillet, D. and Boccaletti, A. and Girard, J. H. and Chauvin, G. (2014) Very deep images of the innermost regions of the β Pictoris debris disc at L′. Astronomy and Astrophysics, 566 . Art. No. A91. ISSN 0004-6361. doi:10.1051/0004-6361/201323130.

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Context. Very few debris discs have been imaged in scattered light at wavelengths beyond 3 μm because the thermal emission from both the sky and the telescope is generally too strong with respect to the faint emission of a debris disc. We present here the first analysis of a high angular resolution image of the disc of β Pictoris at 3.8 μm. Aims. Our primary objective is to probe the innermost parts of the β Pictoris debris disc and describe its morphology. We performed extensive forward modelling to correct for the biases induced by angular differential imaging on extended objects and derive the physical parameters of the disc. Methods. This work relies on a new analysis of seven archival data sets of β Pictoris observed with the NaCo instrument at the Very Large Telescope in the L′ band, including observations made with the Annular Groove Phase Mask vortex coronagraph in 2013. The data analysis consists of angular differential imaging associated with disc forward modelling to correct for the biases induced by that technique. The disc model is subtracted from the data and the reduction performed again in order to minimize the residuals in the final image. Results. The disc is detected above a 5σ level between 0.4′′ and 3.8′′. The two extensions have a similar brightness within error bars. We confirm an asymmetry previously observed at larger distances from the star and at shorter wavelengths: the isophotes are more widely spaced on the north-west side (above the disc apparent midplane) than on the south-east side. This is interpreted as a small inclination of the disc combined with anisotropic scattering. Our best-fit model has an inclination of 86° with an anisotropic Henyey-Greenstein coefficient of 0.36. This interpretation is supported by a new asymmetry detected in the disc: the disc is significantly bowed towards the north-west within 3″ (above the apparent midplane). We also detect a possible new asymmetry within 1″, but at this stage we cannot discern between a real feature and an underlying speckle.

Item Type:Article
Related URLs:
URLURL TypeDescription
Milli, J.0000-0001-9325-2511
Mawet, D.0000-0002-8895-4735
Absil, O.0000-0002-4006-6237
Boccaletti, A.0000-0001-9353-2724
Girard, J. H.0000-0001-8627-0404
Additional Information:© 2014 ESO. Received: 25 November 2013; accepted: 24 April 2014. We would like to thank the referee Dr. A. Brandecker for his constructive comments that helped to significantly improve the quality of the article. J.M. acknowledges financial support from the ESO studentship program and the Labex OSUG 2020 and O.A. acknowledges financial support from a FNRS Research Associate during part of this work. Last, the research leading to these results also received funding from the European Research Council under the European Union’s Seventh Framework Programme (ERC Grant Agreement No. 337569) and from the French Community of Belgium through an ARC grant for Concerted Research Actions.
Funding AgencyGrant Number
European Southern Observatory (ESO)UNSPECIFIED
Fonds de la Recherche Scientifique (FNRS)UNSPECIFIED
European Research Council (ERC)337569
Communauté française de Belgique – Actions de recherche concertéesUNSPECIFIED
Subject Keywords:techniques: high angular resolution; planets and satellites: individual: β Pictoris b; stars: individual: β Pictoris; planetary systems
Record Number:CaltechAUTHORS:20150521-095045983
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Official Citation:Milli, J., Lagrange, A.-M., Mawet, D., Absil, O., Augereau, J.-C., Mouillet, D., . . . Chauvin, G. (2014). Very deep images of the innermost regions of the β Pictoris debris disc at L′. A&A, 566, A91.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57732
Deposited On:21 May 2015 23:20
Last Modified:10 Nov 2021 21:54

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