1 Natural History Museum of Denmark, Natural History Museum of Denmark, Faculty of Science, Københavns Universitet2 Harvard-Smithsonian Center for Astrophysics3 Massachusetts Institute of Technology4 Fundacion Galileo Galilei-INAF5 Instituto de Astrofisica de Canarias6 Université de Liége7 Northwestern University8 Université de Geneve9 Universite de Bordeaux10 University College London11 unknown12 Natural History Museum of Denmark, Natural History Museum of Denmark, Faculty of Science, Københavns Universitet13 Northwestern University14 Universite de Bordeaux15 University College London
We present Rossiter-McLaughlin observations of the transiting super-Earth 55 Cnc e collected during six transit events between 2012 January and 2013 November with HARPS and HARPS-N. We detect no radial velocity signal above 35 cm s–1 (3σ) and confine the stellar v sin i to 0.2 ± 0.5 km s–1. The star appears to be a very slow rotator, producing a very low amplitude Rossiter-McLaughlin effect. Given such a low amplitude, the Rossiter-McLaughlin effect of 55 Cnc e is undetected in our data, and any spin-orbit angle of the system remains possible. We also performed Doppler tomography and reach a similar conclusion. Our results offer a glimpse of the capacity of future instrumentation to study low amplitude Rossiter-McLaughlin effects produced by super-Earths.