P. Bennet et al 2018 ApJL 866 L11
Observations of two new ultra-diffuse galaxies (UDGs), suggest that galaxy interactions could form some UDGs by 1) expanding ordinary dwarf galaxies, or 2) causing a UDG to collapse out of tidal material.
V. M. S. Carrasco et al 2018 ApJ 865 88
The ratio of sunspot umbra to penumbra is found to be roughly the same for sunspots during the Maunder Minimum — a prolonged period of low solar activity that occurred between 1645 and 1715 — as those today.
Sanjaya Paudel et al 2018 AJ 156 166
Deep optical imaging of the gas-rich merging dwarf system KUG 0200-096 reveals a young stellar clump with a stellar mass of 2 × 107 M⊙ at the tip of the faint tidal tail — possibly a tidal dwarf galaxy.
Megan Bedell et al 2018 ApJ 865 68
The C/O and Mg/Si ratios in solar-metallicity stars are measured to be homogeneous to within 10% throughout the solar neighborhood, implying that exoplanets may exhibit less compositional diversity than previously thought.
Nick Indriolo et al 2018 ApJL 865 L18
Orion BN, an object with large proper motion and radial velocity relative to its formation region, shows no evidence of hot water, disfavoring the scenario in which it was accelerated while deeply embedded in molecular gas.
Krzysztof Goździewski and Cezary Migaszewski 2018 ApJS 238 6
Models of the HR 8799 planetary system — with four detected ~10 MJup planets in wide orbits up to ~70 AU — confirm the planets are likely involved in a dynamically robust Laplace 8e:4d:2c:1b resonance chain.