Letter to the Editor
High-sensitivity search for clumps in the Vega Kuiper-belt
V. Piétu1, E. Di Folco2,3, S. Guilloteau4,5, F. Gueth1 and P. Cox1
IRAM, 300 rue de la piscine, 38406
Saint Martin d’Hères
2 CEA Saclay/Service d’Astrophysique, Laboratoire AIM, CEA/DSM/IRFU-CNRS-Université Paris Diderot, 91191 Gif-sur-Yvette Cedex, France
3 LESIA-UMR 8109, CNRS and Observatoire de Paris-Meudon, 5 place J. Janssen, 92195 Meudon, France
4 Université de Bordeaux, Observatoire Aquitain des Sciences de l’Univers, 2 rue de l’Observatoire BP 89, 33271 Floirac, France
5 CNRS/INSU – UMR5804, Laboratoire d’Astrophysique de Bordeaux, 2 rue de l’Observatoire BP 89, 33271 Floirac, France
Received: 27 February 2011
Accepted: 27 April 2011
Context. Previous studies have found that Vega is surrounded by an extended debris disc that is very smooth in the far infrared, but displays possible clumpiness at 850 μm and dust emission peaks at 1.3 mm.
Aims. We reobserved Vega at 1.3 mm with PdBI to constrain its circumstellar dust distribution.
Methods. Our observations of a three-field mosaic have a factor of two higher sensitivity than previous observations.
Results. We detect Vega photosphere with the expected flux, but none of the previously reported emission peaks that should have been detected at the >6σ level, with a sensitivity <1 mK.
Conclusions. This implies that the dust distribution around Vega is principally smooth and circularly symmetric. This also means that no planet is needed to account for dust trapped in mean-motion resonnance.
Key words: radio continuum: stars / stars: individual: Vega / circumstellar matter / methods: observational / instrumentation: interferometers
Based on observations carried out with the IRAM Plateau de Bure Interferometer. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).
Processed data from Fig. 1 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/531/L2
© ESO, 2011