Hot circumstellar material resolved around beta Pic with VLTI/PIONIER

D. Defrère J. Lebreton 1 J. -B. Le Bouquin 1 A. -M. Lagrange 2 O. Absil 3 J. -C. Augereau 1 J. -P. Berger 4 E. Di Folco 5 S. Ertel J. Kluska 1 G. Montagnier 4 R. Millan-Gabet 6 W. Traub 7 G. Zins 1
5 AMOR 2012
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
Abstract : We aim at resolving the circumstellar environment around beta Pic in the near-infrared in order to study the inner planetary system (< 200 mas, i.e., ~4 AU). Precise interferometric fringe visibility measurements were obtained over seven spectral channels dispersed across the H band with the four-telescope VLTI/PIONIER interferometer. Thorough analysis of interferometric data was performed to measure the stellar angular diameter and to search for circumstellar material. We detected near-infrared circumstellar emission around beta Pic that accounts for 1.37% +/- 0.16% of the near-infrared stellar flux and that is located within the field-of-view of PIONIER (i.e., ~200 mas in radius). The flux ratio between this excess and the photosphere emission is shown to be stable over a period of 1 year and to vary only weakly across the H band, suggesting that the source is either very hot (> 1500 K) or dominated by the scattering of the stellar flux. In addition, we derived the limb-darkened angular diameter of beta Pic with an unprecedented accuracy (theta_LD= 0.736 +/- 0.019 mas). The presence of a small H-band excess originating in the vicinity of beta Pic is revealed for the first time thanks to the high-precision visibilities enabled by VLTI/PIONIER. This excess emission is likely due to the scattering of stellar light by circumstellar dust and/or the thermal emission from a yet unknown population of hot dust, although hot gas emitting in the continuum cannot be firmly excluded.
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https://hal.archives-ouvertes.fr/hal-00832266
Contributeur : Marie-Paule Pomies <>
Soumis le : lundi 10 juin 2013 - 14:11:59
Dernière modification le : mercredi 27 juillet 2016 - 14:48:48

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D. Defrère, J. Lebreton, J. -B. Le Bouquin, A. -M. Lagrange, O. Absil, et al.. Hot circumstellar material resolved around beta Pic with VLTI/PIONIER. Astronomy and Astrophysics - A&A, EDP Sciences, 2012, 546, pp.id.L9. <10.1051/0004-6361/201220287>. <hal-00832266>

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