Cometary Science Newsletter Issue 23 Feburary 2017 http://www.cometarysciencenews.org/ - Refereed Journal Papers + Non-Gravitational Acceleration of the Active Asteroids, Hui and Jewitt + Modeling the Nearly Isotropic Comet Population in Anticipation of LSST Observations, Silsbee and Tremaine + Modelling the evolution of a comet subsurface: implications for 67P/Churyumov-Gerasimenko, Guilbert-Lepoutre et al. -- The Cometary Science Newsletter is dedicated to sharing and furthering cometary science. CSN invites contributions from the astronomical and planetary science communities, including abstracts of papers accepted for publication in refereed journals, thesis abstracts, timely notes on particular comets, conference announcements, job announcements, or other relevant and brief scientific communications. Relevant topics include observational, theoretical, and laboratory work concerning comets, but also may include studies of associated phenomena, such as Centaurs, asteroid-comet transition objects, debris disks, and protoplanetary disks.