Amir Siraj and Abraham Loeb 2020 ApJL 899 L24
An equal-mass, temporary binary companion to the Sun in the solar birth cluster at a separation of ~1,000 au could have formed the observed population of outer Oort Cloud objects and captured the hypothetical Planet Nine.
Francisco Villaescusa-Navarro et al 2020 ApJS 250 2
The Quijote simulations are a set of 44,100 full N-body cosmological simulations; a single redshift contains more than 8.5 trillion particles, allowing identification of billions of dark matter halos and cosmic voids.
Toshihiko Kadono et al 2020 ApJL 899 L22
An impact experiment performed on the surface of the C-type asteroid Ryugu using an instrument carried by JAXA’s Hayabusa2 spacecraft provided measurements of large boulders and regolith grains on the asteroid.
R. Li et al 2020 ApJ 899 30
286 new high-probability galaxy-scale strong-lens candidates have been found in the Kilo-Degree Survey data release 4 using machine learning, including 26 objects particularly suitable for follow-up.
Allison Youngblood et al 2020 AJ 160 100
A transmission spectrum is extracted from Hubble lunar eclipse spectra during the 2019 January total lunar eclipse, providing the first near-ultraviolet observation of Earth as an exoplanet.
Erika Hamden et al 2020 ApJ 898 170
The 2018 flight of the FIREBall-2 Balloon telescope, intended to observe faint emission from the circumgalactic medium of z ~ 0.7 galaxies for the first time, ended due to a hole in the balloon; the team will try again in 2021.