Karen J. Meech

TL;DR: In situ observations show that comet Hartley 2 is an unusually hyperactive comet, and this nucleus is outgassing primarily because of CO2, which drags chunks of ice out of the nucleus.

TL;DR: Observations and analysis of the object 1I/2017 U1 (‘Oumuamua) that demonstrate its extrasolar trajectory, and that enable comparisons to be made between material from another planetary system and from the authors' own, reveal it to be asteroidal with no hint of cometary activity despite an approach within 0.25 astronomical units of the Sun.

TL;DR: Spitzer Space Telescope imaging spectrometer observations of comet 9P/Tempel 1 during the Deep Impact encounter returned detailed, highly structured, 5- to 35-micrometer spectra of the ejecta, and the atomic abundance of the observed material is consistent with solar and C1 chondritic abundances.

TL;DR: This report continues the practice where the IAU Working Group on Cartographic Coordinates and Rotational Elements revises recommendations regarding those topics for the planets, satellites, minor planets, and comets approximately every 3 years, and recommends that planning and efforts be made to make controlled cartographic products.