Rotational variation of the linear polarization of the asteroid (3200) Phaethon as evidence for inhomogeneity in its surface properties

This work was supported via a grant (ST/M000834/1) from the UK Science and Technology Facilities Council. We gratefully acknowledge observing grant support from the Institute of Astronomy and Rozhen National Astronomical Observatory, Bulgarian Academy of Sciences. The Calern Asteroid Polarimetric Survey (CAPS), carried out at Calern in the framework of C2PU, is a collaboration between INAF –Torino Astrophysical Observatory and the Observatoire de la cote d’Azur. The GOTO Observatory is a collaboration between the University of Warwick and Monash University (as the Monash–Warwick Alliance), Armagh Observatory & Planetarium, the University of Sheffield, the University of Leicester, the National Astronomical Research Institute of Thailand (NARIT), the Instituto de Astrofsica de Canarias (IAC), the University of Turku, and Rene Breton (University of Manchester). TB acknowledges financial support by contract DN 18/13-12.12.2017 with the Bulgarian NSF. This research was made possible through the use of the AAVSO Photometric All-Sky Survey (APASS), funded by the Robert Martin Ayers Sciences Fund. The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Gran