Kosuke Namekata et al 2019 ApJ 871 187
An analysis of 5,356 active solar-type stars observed by Kepler reveals that starspot lifetimes are ~10–350 days when spot areas are 0.1%–2.3% of the solar hemisphere, shorter than expected in analogy with the Sun.
Scott J. Kenyon and Benjamin C. Bromley 2019 AJ 157 79
N-body simulations disfavor undiscovered satellites in the Pluto–Charon system inside Hydra’s orbit; orbits with a semimajor axis >1.1x that of Hydra, on the other hand, are stable on timescales >150–300 Myr.
B. van der Holst et al 2019 ApJL 872 L18
Predictions of the first Parker Solar Probe close encounter suggest that the probe was close to the heliospheric current sheet, the trajectory was in the slow solar wind, and the plasma along the trajectory was unstable.
Karina T. Voggel et al 2019 ApJ 871 159
The supermassive black hole number density caused by stripped galaxy nuclei is estimated at 0.002–0.008 Mpc−3, representing a significant fraction (8%–32%) of the supermassive black hole density in the local universe.
Sven Köppel et al 2019 ApJL 872 L16
A nonlinear universal relation is shown to exist between the threshold mass for prompt collapse of a neutron star (NS) and the maximum compactness; from this, future observations may constrain the NS equation of state.
Michael Greklek-McKeon and Drake Deming 2019 AJ 157 77
The EVEREST pipeline is used to evaluate false-positive exoplanet candidates from the K2 mission, identifying 6 systems previously flagged as planetary candidates that are instead eclipsing binaries.