For #ACM2026, @harrisonagrusa.bsky.social suggests up to 30% contact binaries in the asteroids resulting from large collisions. Radar samples of near-Earth asteroids have counted fewer than that - but not all of the contact binaries would be recognized.

Harrison Agrusa@harrisonagrusa.bsky.social · last mo.

I’ve been exploring gravitational reaccumulation after asteroid catastrophic disruptions and am finding contact binaries are super common outcomes! I can’t help but notice how similar Torifune looks compared to this fragment from one of my simulations, which I will present tomorrow at #ACM2026

I’ve been exploring gravitational reaccumulation after asteroid catastrophic disruptions and am finding contact binaries are super common outcomes! I can’t help but notice how similar Torifune looks compared to this fragment from one of my simulations, which I will present tomorrow at #ACM2026

Andy Rivkin@asrivkin.bsky.social · last mo.

Torifune!! It looks like another Itokawa! As JB says, it’s a great time for asteroid studies, and hopefully we’ll hear a lot more over the course of the #ACM2026 meeting!

I've been working on a new N-body code and wanted a fun way to demonstrate that the contact physics is correct (at least qualitatively). So here is a self-gravitating Newton's cradle!

New paper out 🥳 Using data from #NASA #Lucy mission and a series of numerical simulations, we show that #Selam, the moon of #Dinkinesh, likely formed through a series of at least four low-velocity collisions between similarly sized moonlets. www.nature.com/articles/s41...

Multiple moonlet mergers as the origin of the Dinkinesh-Selam system - Nature Communications

Space missions imaging small asteroid moons revealed the variety in shapes. Here, the authors show that repeated low-speed collisions can explain the shape of Selam, which is the smaller component in ...

nature.com

Current status: gardening with a view. Had to harvest ~1/4 of my onions early because somebody has a habit of trampling on them in search of the ball…

Had a fun time being a part of this paper where we used a combination of SPH and N-body simulations to explore how asteroid satellites form from collisions. arxiv.org/abs/2505.03325

Satellite formation around the largest asteroids

Satellites around large asteroids are preferentially found among those with the most rapid rotation and elongated shape. The taxonomic statistics are similarly skewed; in total, 13 asteroids larger th...

arxiv.org

2 hours and 4 minutes to the closest approach of Lucy with #asteroid (52246) Donaldjohanson [DJ]. ↔️ current distance to DJ: 100 thousand km ☀️ current phase angle: 13.98° 🪨 estimated size of DJ on L'LORRI camera: 6-10 pixels ▶️ www.whereIsLucy.space #PlanetSci #SciComm

In Japan for the next 10 days for a few exciting meetings. Today and tomorrow, I am at JAXA’s ISAS for a Hayabusa2# science team meeting. What a great excuse to visit when the cherry blossoms are in full bloom!

Working up here at the Obervatoire de la Côte d'Azur, #Nice today and gave a talk on #Comet activity modelling this morning #PlanetSci. Thanks to everyone who came and thanks very much to @harrisonagrusa.bsky.social for hosting me!

Playing around with some renderings of DART impact ejecta simulations. It’s amazing what you can do with @matplotlib.org and @reboundbot.bsky.social !

Happy to announce that I’ve been selected as a participating scientist on NASA’s Lucy mission. I can’t wait to join the team and explore the Trojans! science.nasa.gov/uncategorize...

NASA Selects Participating Scientists to Join Lucy Asteroid Mission - NASA Science

NASA has selected eight participating scientists to join its Lucy mission to the Jupiter Trojan asteroids. These asteroids are remnants of our early

science.nasa.gov

New (to me) handmade table and chairs found at a flea market in Nice. Restoring it now with some beeswax. €100 and will probably outlive me. This room is finally coming together!

I decided it would be a good idea to procrastinate on job applications and play some Kerbal Space Program instead. Using a mod to play with a 1/9 scale real solar system, did a nice Voyager style mission. Here are my Jupiter and Neptune/Triton flybys :)

I found a fun Easter egg in For All Mankind. They used real DART papers as props for a scene related to altering the orbit of an asteroid! On the left is Rivkin et al. 2021 and on the right is Hirabayashi et al. 2022.