Csilla E. Kalup et al 2021 ApJS 254 7
Kepler K2 measurements of 101 Jovian Trojan asteroids show a rotation dichotomy with separation at ~100 hrs and low densities that support an outer solar system origin for this asteroid population.
Thomas Connor et al 2021 ApJ 911 120
Deep Chandra observations of PSO J352.4034−15.3373, a quasar at z = 5.831 that is one of the radio-loudest quasars in the early universe, revealed a structure that may represent the most distant quasar jet yet seen in X-rays.
Steven N. Longmore et al 2021 ApJL 911 L16
New analysis suggests that stars located in overdensities have a factor of 1.6–2.0 excess in the number of single-planet systems compared to field stars, and field stars contain a greater fraction of multiplanet systems.
Kevin K. Hardegree-Ullman et al 2021 AJ 161 219
Spitzer photometry has been used to validate a sixth planet in the planetary system K2-138, which had previously been shown by citizen science discoveries to contain one super-Earth and four sub-Neptunes.
K. J. Napier et al 2021 Planet. Sci. J. 2 59
New analysis of the properties of 14 Dark-Energy-Survey-detected extreme trans-Neptunian objects shows they are consistent with a uniform population, suggesting Planet Nine is not necessary to explain their behavior.
Krista Lynne Smith et al 2021 ApJ 911 43
The TESS exoplanet-hunting mission recently detected the rising and decaying optical afterglow of GRB 191016A, a long gamma-ray burst detected by Swift-BAT; such detections by TESS are likely to be made ~once per year.