Matías Gárate et al 2019 ApJ 871 53

Reactivation of a dead zone in the protoplanetary disk surrounding RW Aur A could explain various dimming events in recent years that decreased its brightness by ~2 mag for periods of months to years.

May G. Pedersen et al 2019 ApJL 872 L9

TESS data has allowed the detection and classification of new variable O and B stars, including 23 multiperiodic pulsators, 6 eclipsing binaries, 21 rotational variables, and 25 stars with stochastic low-frequency variability.

S. Issaoun et al 2019 ApJ 871 30

New observations of the supermassive black hole Sagittarius A* with the with the Global Millimeter VLBI Array — now with ALMA added — reveal its size and shape and suggest that it is disk, not jet, dominated.

Michael E. Brown and Konstantin Batygin 2019 AJ 157 62

Estimates suggest that the probability that the observed clustering of distant Kuiper Belt Objects is due to observational bias is only ~0.2%, possibly strengthening the argument for the existence of Planet Nine.

Jun Yang et al 2019 ApJ 871 29

Planetary heat transport from the day to night side is shown to be dominated by a planet’s ocean at the outer edge of the habitable zone, but by its atmosphere at the inner edge of the habitable zone.

Ester Marini et al 2019 ApJL 871 L16

Spitzer Space Telescope observations have revealed a small sample of oxygen-rich, asymptotic giant branch stars in the Large Magellanic Cloud that are surrounded by dust primarily composed of solid iron.