Light curves of ten Centaurs from K2 measurements

Here we present the results of visible range light curve observations of ten Centaurs using the Kepler Space Telescope in the framework of the K2 mission. Well defined periodic light curves are obtained in six cases allowing us to derive rotational periods, a notable increase in the number of Centaurs with known rotational properties. The low amplitude light curves of (471931) 2013 PH44 and (250112) 2002 KY14 can be explained either by albedo variegations, binarity or elongated shape. (353222) 2009 YD7 and (514312) 2016 AE193 could be rotating elongated objects, while 2017 CX33 and 2012 VU85 are the most promising binary candidates due to their slow rotations and higher light curve amplitudes. (463368) 2012 VU85 has the longest rotation period, P = 56.2 h observed among Centaurs. The P > 20 h rotation periods obtained for the two potential binaries underlines the importance of long, uninterrupted time series photometry of solar system targets that can suitably be performed only from spacecraft, like the Kepler in the K2 mission, and the currently running TESS mission. •Light curves of ten Centaurs observed with the Kepler Space Telescope in the K2 mission are presented•Rotation periods are derived for six targets: 2002 KY14, 2009 YD7, 2013 PH44, 2012 VU85, 2016 AE193 and 2017 CX33•The rotation period of P = 56.2 h of 2012 VU85 is the longest ever observed among Centaurs•The long period (P>20h) targets are also candidate binary systems, as revealed by our analysis•The results emphasise the importance of long, uninterrupted photometry by space telescopes, like Kepler/K2 and TESS