High-sensitivity search for clumps in the Vega Kuiper-belt
Résumé
We present new observations of the Vega system with the Plateau de Bure Interferometer. The debris disc around the prototypic Vega is known to extend up to > 800AU, with a very smooth far IR emission, and possible clumpiness at sub-mm wavelengths. Our observations of a three-field mosaic at 1.3mm have a factor of two higher sensitivity than previous works. The stellar photosphere is detected with the expected flux, but we find no evidence for the previously reported dust emission peaks that should have been detected at the > 6 level. We derive upper limits for the dust continuum emission that are compatible with observations at shorter wavelengths. All angularly resolved observations indicate that the disc emission around Vega is smooth and circularly symmetric, hence do not require the gravitational influence of a giant planet to sculpt asymmetries, at the current level of detection.