Astronomers have carried out the first systematic search for radio emission from exoplanets that have been imaged directly, an important step for constraining the magnetic fields, internal structure, and habitability of these worlds.
I. Bartos et al 2021 ApJ 921 45
Given the properties of neutrino-emitting sources and the IceCube detector, blazars likely produce only 11% of neutrinos detected, while active galactic nuclei and tidal disruption events contribute 50%, and 10% arise from a still-unknown source.
Junko Ueda et al 2021 ApJS 257 57
Millimeter observations of molecular lines in 28 local galaxies that are in the midst of merging suggest that the act of merging enhances star formation, even after coalescence is complete.
Noah Jäggi et al 2021 Planet. Sci. J. 2 230
Young Mercury likely lost only a tiny fraction of its mass through the escape of its early atmosphere, suggesting that its unusual interior structure and surface composition are due to its formation location.
C. E. Woodward et al 2021 ApJL 922 L10
Coronal lines appeared in the spectrum of Nova Herculis 2021 just 11.5 days after its onset — the earliest emergence seen in any classical nova — even before there was an identifiable source of ionization to generate them.
Alessandra Canta et al 2021 ApJ 922 62
The molecule cyanomethyl (CH2CN) was previously detected around protostars and in pre-stellar cores and molecular clouds, but recent observations place the molecule in a new location: protoplanetary disk TW Hydrae.