Accurate and precise radius estimates of transiting exoplanets are critical for understanding their compositions and formation mechanisms. To know the planet, we must know the host star in as much detail as possible. We present first results from the K2-HERMES project, which uses the HERMES multi-object spectrograph on the Anglo-Australian Telescope to obtain R∼28,000 spectra of up to 360 stars in one exposure. This ongoing project aims to derive self-consistent spectroscopic parameters for about half of K2 target stars. We present complete stellar parameters and isochrone-derived masses and radii for 46 stars hosting 57 K2 candidate planets in Campaigns 1-3. Our revised host-star radii cast severe doubt on three candidate planets: EPIC\,201407812.01, EPIC\,203070421.01, and EPIC\,202843107.01, all of which now have inferred radii well in excess of the largest known inflated Jovian planets.
@article{arxiv.1712.06774,
title = {The K2-HERMES Survey. I. Planet Candidate Properties from K2 Campaigns 1-3},
author = {Robert A. Wittenmyer and Sanjib Sharma and Dennis Stello and Sven Buder and Janez Kos and Martin Asplund and Ly Duong and Jane Lin and Karin Lind and Melissa Ness and Tomaz Zwitter and Jonathan Horner and Jake Clark and Stephen R. Kane and Daniel Huber and Joss Bland-Hawthorn and Andrew R. Casey and Gayandhi M. De Silva and Valentina D'Orazi and Ken Freeman and Sarah Martell and Jeffrey D. Simpson and Daniel B. Zucker and Borja Anguiano and Luca Casagrande and James Esdaile and Marc Hon and Michael Ireland and Prajwal R. Kafle and Shourya Khanna and J. P. Marshall and Mohd Hafiz Mohd Saddon and Gregor Traven and Duncan Wright},
journal= {arXiv preprint arXiv:1712.06774},
year = {2018}
}