Lauri SiltalaMay 20

I am going to give Mastodon another shot and try to get active here :) Goal: post one cool (at least to me) thing per day.

Lets begin: last week I was at the Asteroid Radar Modeling Workshop in Spain (https://sites.google.com/view/armw25/) where I learned a lot about planetary radar data and started working on asteroid shape modeling based on said data.

Attached the fruit of my labors - my WIP shape model for the near-Earth asteroid Agni. Not yet perfect - I will continue refining it!

10/10 workshop!

ARMW '25

Welcome to the Asteroid Radar Modeling Workshop 2025! The Asteroid Radar Modeling Workshop '25 (ARMW25) is a workshop that will provide the opportunity to learn the use of the tool SHAPE (Magri et al. 2007 and other references; see "Resources" page) to develop asteroid shape models from radar and

Show threadJanne MorenMay 20

@siltala
Welcome back!

Another tip is to use hashtags. They're both a great way for people to find your posts and also for you to find posts by other people.

Show threadLauri SiltalaMay 20
@jannem Thanks! Indeed, using hashtags is a good reminder. I will try to remember to do so 😅
Show threadJanne MorenMay 20

@siltala
Don't worry; you'll get it. Also follow lots of people. That's the way to build a good feed. Try @lisamelton for a firehose of content.

About your post: is this method akin to CT scanning, just that you rely on the object to rotate over time to get enough samples?

Show threadLauri Siltala

@jannem Both sampling across the entire rotation phase and multiple viewing angles (orientation of an #asteroid relative to Earth is never constant)! are critical.

#radar data in use here is all from #Arecibo - the LPI has most of it at https://www.lpi.usra.edu/resources/asteroids/asteroid/?asteroid_id=2010LE15 if you want to see. With these observations, one beams a radio signal to the asteroid and observes the echo returned. Interesting observed parameters include Doppler shift, polarization and echo power.

May 20 at 11:46amWeb
Show threadLauri SiltalaMay 20

@jannem Also included are optical lightcurves from #ALCDEF ( https://alcdef.org/ ) or observations of Agni's brightness over time.

Essentially, what we have is an inverse problem where the aim is to fit a 3d model and rotation state into the observations that reproduces said observations as well as possible.

ALCDEF Database

A database with millions of asteroid time-series photometry observations