NICER observation list: Target ID 462309

We request 115 ksec of Nicer observing time to study the solar wind interaction of two comets, 19P/Borrelly and 67P/Churyumov-Gerasimenko, whose plasma environments were studied in situ by the Deep Space 1 and Rosetta spacecraft, respectively. We will use the proposed observations to study how comets respond to time-variable solar wind conditions, to provide global context to the local measurements conducted by the spacecraft, and to investigate the source of poorly understood cometary 1-2 keV emission features.