Articles of note in MNRAS (Monthly Notices of the Royal Astronomical Society) for April:
Volume 538, Issue 2
–
Volume 538, Issue 3
Mariblanca-Escalona, I. Lara, L. M. Moreno, F. et al. Activity of comet 7P/Pons–Winnecke during the 2021 apparition Page 1329 staf370
Voitko, A. Kleshchonok, V. Shubina, O. et al. Photometric study of eight distant comets Page 1609 staf400
Volume 538, Issue 4
Fu, X. Soldini, S. Equilibrium point evolution and the associated characteristic curves of an asteroid Page 2245 staf419
Cannon, R. E Rożek A. Brozović M. et al. Shape and spin state model of contact binary (388188) 2006 DP14 using combined radar and optical observations Page 2311 staf371
Rondón, E. Roig, F. Lazzaro, D. et al. Secular light curves of periodic comets observed by SWAN/SOHO Page 2869 staf454
What causes the activity (mass loss and ejection) of comets? Ten years after Rosetta, the question still stands. Mariblanca-Escalona et al. and Voitko et al., and to an extent Rondón et al. give us more data points. The difference is that Rondón et al. look at comets with the SoHO mission, in the sunward direction. As comets leave the outer Solar System and approach the Sun, they get warmer from greater insolation. The nature of activity shifts from more-volatile ices (such as frozen methane, ammonia, hydrogen sulfide etc.) to water ice, to heavier substances (e. g., heavier organics, metal sulfides, etc.). The nearest Sun-passes can boil rock itself.
Cannon et al. describe the dynamics of binary(?) asteroid 2006 DP14. Unlike an asteroid moon (but like many comets), the two bodies (lobes?) are in contact. The process of merging, touching (with scraping?), and finally fusing is a history we would like to unravel.
In a loosely similar vein, Fu et al. consider the gravity field around an asteroid. Like Cannon et al., we would like to use probes, landers, etc. about small bodies, with or without the scraping. Given nonspherical small bodies, this is not a simple math equation.