Courtney Carter et al 2021 ApJ 908 208
More than 70% of a sample of 482 very metal poor stars near the galactic disk are on prograde orbits and this fraction increases toward lower metallicities, suggesting a heterogeneous origin for this population.
Bradley M. S. Hansen and Ben Zuckerman 2021 AJ 161 145
Interstellar travel — necessary for a civilization to survive its host star’s evolution — can be made more feasible by waiting for the close passage of another star; another star typically passes within ~1,500 au within ~1 Gyr.
Ralph D. Lorenz et al 2021 Planet. Sci. J. 2 24
A dune site near the Selk crater on Titan has been selected as the first landing site for the Dragonfly mission due to practical mission considerations as well as the likely presence of exposed deposits of water-rich material.
Xueshan Zhao et al 2021 ApJ 908 117
Using updated parameter values for the continuum-fitting technique, a new spin of a* > 0.9985 is estimated for the black hole in Cygnus X-1, confirming that this black hole’s spin is extreme.
Erica Hammerstein et al 2021 ApJL 908 L20
The sample of galaxies hosting the first 19 tidal disruption events (TDEs) detected with ZTF is dominated by compact “green valley” galaxies — potentially explainable if TDE rate is temporarily enhanced following a merger.
C. Swastik et al 2021 AJ 161 114
A large scatter in metallicity is found in a subsample of 18 stars known to host wide-orbit directly imaged planets, suggesting a metal-rich environment may not be necessary to form massive planets at large orbital distances.