Guo Chen et al 2021 ApJL 913 L16

Low-resolution transmission spectra of the puffy hot Jupiter HAT-P-65b reveal evidence for titanium oxide in this planet’s relatively clear atmosphere.

Donghyeon J. Khim et al 2021 ApJS 254 27

Simulations point to 4 channels that generate misalignment of the stars and gas in galaxies: mergers (35%), interaction with nearby galaxies (23%), interaction in dense environments (21%), and secular evolution (21%).

Cristina M. Dalle Ore et al 2021 Planet. Sci. J. 2 83

Examination of the H₂O ice phase on the surface of Dione, one of Saturn’s icy satellites, supports the hypothesis that Dione might have been recently active and is still harboring a body of liquid water under its crust.

T. Wevers et al 2021 ApJ 912 151

Multiwavelength observations of the TDE AT2018fyk over two years show three distinct accretion states and two state transitions between them, very similar to the behavior of stellar-mass black holes in outburst.

Shantanu P. Naidu et al 2021 ApJL 913 L6

Observations of 2020 CD3 from the Dark Energy Camera and Catalina Sky survey from 2018–19 allow us to calculate that this asteroid was captured into a geocentric orbit in September 2017, temporarily becoming a minimoon.

Trevor J. David et al 2021 AJ 161 265

A study of systems in the California–Kepler Survey sample suggests that the size distribution of close-in exoplanets and the precise location of the radius valley — a bifurcation in this distribution — evolve over gigayears.