M. Ajello et al 2021 ApJS 252 13
The first Fermi-Large Area Telescope solar flare catalog, covering the 24th solar cycle, contains 45 Fermi-LAT solar flares with emission in the γ-ray energy band detected between 2010 and 2018.
Feige Wang et al 2021 ApJL 907 L1
The most distant quasar yet discovered, J0313−1806, demonstrates the existence of a supermassive black hole just ~670 million years after the Big Bang, significantly challenging models of black-hole growth.
S. O. Kepler et al 2021 ApJ 906 7
The pulsating hydrogen atmosphere white dwarf star G 117-B15A, observed since 1974, has a stable pulsation period that varies by only 1 second in 6.2 million years, making it an exceptional optical clock.
Eric Agol et al 2021 Planet. Sci. J. 2 1
Fresh analysis of the TRAPPIST-1 exoplanet system using 4 years of transit times from the Spitzer Space Telescope, as well as additional data and simulations, provides new constraints on the properties of the system.
Steve Bryson et al 2021 AJ 161 36
Using the Kepler DR25 planet candidate catalog and Gaia-based stellar properties, the occurrence rate of habitable-zone rocky planets around main sequence stars is estimated as ~0.37–0.88 planets per star.
Roman R. Rafikov 2020 ApJL 905 L35
Calculations show that several of the S stars that orbit extremely close to the supermassive black hole at our galaxy’s center experience relativistic Doppler boosting that increases their photometric variability by more than 6%.