We report on a search for low mass companions within 10 AU of the star Fomalhaut, using narrow band observations at 4.05 microns obtained with the Apodizing Phase Plate (APP) coronagraph on the VLT/NaCo. Our observations place a model dependent upper mass limit of 12-20 Jupiter masses from 4 to 10 AU, covering the semi-major axis search space between interferometric imaging measurements and other direct imaging non-detections. These observations rule out models where the large semi-major axis for the putative candidate companion Fomalhaut b is explained by dynamical scattering from a more massive companion in the inner stellar system, where such giant planets are thought to form.
@article{arxiv.1212.1459,
title = {Coronagraphic observations of Fomalhaut at solar system scales},
author = {M. A. Kenworthy and T. Meshkat and S. P. Quanz and J. H. Girard and M. R. Meyer and M. Kasper},
journal= {arXiv preprint arXiv:1212.1459},
year = {2015}
}