Abhimat Krishna Gautam et al 2019 ApJ 871 103
An 11.5-year adaptive-optics study of variability at the galactic center reveals that roughly half the sample shows variability: ~52% of known early-type young stars and ~43% of known late-type giants.
F. Massaro et al 2019 ApJS 240 20
Despite their radio morphological classification and/or their optical classification, radio galaxies in the local universe tend to live in galaxy-rich large-scale environments that have similar characteristics and richness.
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.