Can’t forget Astronomical Journal. For October (vol. 168, issue 4):
Kwon, Y. G. Bagnulo, S. Markkanen, J. et al. The Pre-perihelion Evolution of the Activity of Comet C/2017 K2 (Pan-STARRS) during the Water Ice-line Crossover a 164 ad6b15
Morrison, S. G. Strauss, R. H. Trilling, D. E. et al. Infrared Colors of Small Serendipitously Found Asteroids in the UKIRT Hemisphere Survey a 180 ad6909
Gowanlock, M. Trilling, D. E. McNeill, A. et al. M. Asteroid Period Solutions from Combined Dense and Sparse Photometry a 181 ad6cdd
Strauss, R. McNeill, A. Trilling, D. E. et al. The DECam Ecliptic Exploration Project (DEEP). VII. The Strengths of Three Superfast Rotating Main-belt Asteroids from a Prelimina… a 184 ad7366
Comets ‘are like cats- they have tails, and do what then want’, said cometologist David Levy. Here, Kwon et al. brief us on what comet C/2017 K2 (Comet Pan-STARRS) did, such as its tail forming and growing. What we want is a better handle on comet activity, and its relevant processes/compositions. The issue still exists, even after Rosetta- orbiting AND landing did not settle things.
I write of the NASA IRTF (Infrared Telescope Facility). Also on Maunakea is the UKIRT (United Kingdom Infrared Telescope), same general idea. And likewise, it can do follow-up observations, to characterize asteroids (and comets). Morrison et al. start briefing us on the near-infrared (J and K band) data taken by UKIRT, without even trying- small bodies just wander into the field of view.
Gowanlock et al., similarly, detect many asteroids with the wide-field Zwicky Transient Facility (ZTF, in Southern California) and TESS (Transiting Exoplanet Survey Satellite, in space). The two are complementary: ZTF is nicely sensitive but limited to night hours, while TESS can stare for weeks, but only with a small lens. Between them, do we get a fuller picture of an asteroid’s spin, merging two datasets for fuller time coverage? Apparently so. ZTF is also being used as a precursor/prototype for Vera Rubin, so this is especially useful to see.
And speaking of rotation, there exist fast- and superfast-rotators. The “spin barrier” of ~2 hours defines solid vs. non-‘solid’ asteroids. Faster than that, and a body cannot hold together by gravity alone; it must be mechanically strong. Using the existing DECam, asteroid spins are taken and used to tell us of asteroid strengths. Three such bodies in particular- 2022 KB9, 2015 VP174, and “Iogm1Zl” (internal designation) seem to be nontrivially strong. Are they just monolithic rock, or is there a cohesion- ‘grip’- in the chunks? How much cohesion… indicating what sort of rock?