Hot circumstellar material resolved around beta Pic with VLTI/PIONIER
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.
Keywords
Cite
@article{arxiv.1210.1914,
title = {Hot circumstellar material resolved around beta Pic with VLTI/PIONIER},
author = {D. Defrère and J. Lebreton and J. -B. Le Bouquin and A. -M. Lagrange and O. Absil and J. -C. Augereau and J. -P. Berger and E. di Folco and S. Ertel and J. Kluska and G. Montagnier and R. Millan-Gabet and W. Traub and G. Zins},
journal= {arXiv preprint arXiv:1210.1914},
year = {2012}
}
Comments
4 pages, 4 figures, accepted for publication in A&A