Michael W. Coughlin et al 2019 ApJL 885 L19

Even with single-detector gravitational-wave events localized to thousands of square degrees, systematic kilonova discovery is feasible with follow-up campaigns with telescopes like ZTF and Palomar Gattini-IR.

Frédérique Baron et al 2019 AJ 158 187

Based on direct-imaging observations of a sample of 344 stars in nearby young associations, the occurrence rate for companions with masses of 1–20 Jupiter masses in the range of 5–5000 AU is ~11%.

Kyle Kremer et al 2019 ApJ 885 2

N-body models show that 10%–50% of primordial planetary systems in dense star clusters can be broken through dynamical encounters over a cluster’s full lifetime, populating clusters with “free-floating” planets.

Hadis Goodarzi et al 2019 ApJS 244 37

Analysis of the light curves of 1740 flare stars indicates that flare frequency and the total power of flares correlates with increasing relative magnetic feature coverage and contrast in F–M-type stars.

Daniel R. Weisz et al 2019 ApJL 885 L8

Investigation of 20 faint M31 satellites indicates they all quenched 3–9 billion years ago, in contrast to Milky Way satellites that are either faint with ancient quenching times, or luminous with recent quenching times.

P. M. Shober et al 2019 AJ 158 183

An extremely slow fireball was recently observed travelling at just 11 km/s. This object was a “minimoon”, or a temporarily captured orbiter — an object gravitationally captured by the Earth-Moon system.