Polarimetric observations from the
European Southern Observatory in 2012 revealed that both
74P/Smirnova–Chernykh and 152P/Helin–Lawrence still produce cometary activity even at large heliocentric distances, suggesting that both comets were relative newcomers to the inner Solar System and thus contain large reservoirs of volatile material in their respective interiors. The
nucleus of 152P/Helin–Lawrence is estimated to be around in diameter, based on observations conducted using the
Hubble and
Keck telescopes in 1998. == Notes ==