Between my normal meetings and writing, I'm watching a few talks at the American Astronomical Society's (AAS) Division for Dynamical Astronomy (DDA) annual meeting this week.
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Helena Buschermohle (Instituto Nacional de Pesquisas Espacias) what happens to moons around circumbinary planets? As planets migrate inwards, Hill sphere gets smaller and moons would become unbound. HAHA she calls stable moons "smoons" and a moon that becomes a planet a "ploonet"
All circumbinary exoplanets discovered so far are gas giants, but maybe moons could be habitable, now that we know some moons survive migration.
@sundogplanets Wow, I think I identify as circumbinary now.
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Most super earth systems are not resonant (they don't sound so nice), and lots are near-resonant and sound a little out of tune (some sound quite ominous!)
If you throw a few Plutos in to the system, scattering will disrupt the chain that formed, sometimes leaves them near but not quite in the resonance.
Ends with a note to Kepler (the astronomer) who thought the planets should be in perfect resonance, if not now, maybe when formed. Cool!
@sundogplanets respnance may be an objection for KAM theory (and therefore, the stability of the respective solar system), though
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Oooo he's got a bunch of orbital sonification on his website! https://shadden.github.io/sonification/
Oooo really neat to hear a chord change during an N-body simulation when stability is lost and a planet swaps to a different resonance.
Resonant chain migration behaves like masses on springs, says it's like vibrato! Cool.
"So that's a lot of fun, but so what?" Unstable modes grow or decay depending on how eccentricities are damped.
@sundogplanets this stuff is super fascinating.
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Most super earth systems are not resonant (they don't sound so nice), and lots are near-resonant and sound a little out of tune (some sound quite ominous!)
If you throw a few Plutos in to the system, scattering will disrupt the chain that formed, sometimes leaves them near but not quite in the resonance.
Ends with a note to Kepler (the astronomer) who thought the planets should be in perfect resonance, if not now, maybe when formed. Cool!
Leia Shen & Kavi Dey (Harvey Mudd College) current categorization looking for asteroid dynamical families takes ~30 minutes of computation per asteroid. Vera Rubin observatory will discover 10 million more asteroids. Using machine learning and computationally cheaper asteroid properties to find families. Code is available, but they only gave it as QR code not a link...sigh.
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Leia Shen & Kavi Dey (Harvey Mudd College) current categorization looking for asteroid dynamical families takes ~30 minutes of computation per asteroid. Vera Rubin observatory will discover 10 million more asteroids. Using machine learning and computationally cheaper asteroid properties to find families. Code is available, but they only gave it as QR code not a link...sigh.
David Minton (Purdue): Starts with really cool animation of Moon getting blasted by asteroids! Compares craters to dino footprints. Makes the point that better data (seeing smaller craters) changes the story dramatically
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David Minton (Purdue): Starts with really cool animation of Moon getting blasted by asteroids! Compares craters to dino footprints. Makes the point that better data (seeing smaller craters) changes the story dramatically
Ben Cassese (MPC): here comes the flood of Solar System small body data! Expect 200 million observations per year from Rubin, + 200 million from NEO Surveyor. MPC has to quickly link previous observations into new orbits, this is hard. Will need machine learning to process everything.
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Ben Cassese (MPC): here comes the flood of Solar System small body data! Expect 200 million observations per year from Rubin, + 200 million from NEO Surveyor. MPC has to quickly link previous observations into new orbits, this is hard. Will need machine learning to process everything.
@sundogplanets
Certainly something like the BOINC project. -
David Minton (Purdue): Starts with really cool animation of Moon getting blasted by asteroids! Compares craters to dino footprints. Makes the point that better data (seeing smaller craters) changes the story dramatically
@sundogplanets Thanks for today’s threads, it’s been really interesting.
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Ben Cassese (MPC): here comes the flood of Solar System small body data! Expect 200 million observations per year from Rubin, + 200 million from NEO Surveyor. MPC has to quickly link previous observations into new orbits, this is hard. Will need machine learning to process everything.
Paul Wiegert (U. Western Ontario): finding interstellar meteors is really hard! Lots of meteors are from comets with high-eccentricity orbits, hard to get good enough data to measure meteor pre-impact orbits. There *are* interstellar meteors, just not as many as that Harvard astronomer (who the speaker did not name) seems to think, and none have been conclusively discovered yet.
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Oooo he's got a bunch of orbital sonification on his website! https://shadden.github.io/sonification/
Oooo really neat to hear a chord change during an N-body simulation when stability is lost and a planet swaps to a different resonance.
Resonant chain migration behaves like masses on springs, says it's like vibrato! Cool.
"So that's a lot of fun, but so what?" Unstable modes grow or decay depending on how eccentricities are damped.
@sundogplanets Really Cool!
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Konstantin Batygin (Caltech): most common planets are super-Earths on very short orbits. How do they not fall into their star? How do they pick which resonance to lock in to? (Bonus points for joke about a system with a 6:7 resonance for everyone with middle-school-aged kids)
Giant equation in a confetti explosion (this guy likes giving talks). Shows that 6:7 resonance requires planets to form simultaneously at 1-3AU: the "planet factory ring"
@sundogplanets
Do we still have sampling issues? Is “most common planets are super-Earths on very short orbits” because those are easier to detect than super-Earths on longer orbits, or sub-Earths? -
Leia Shen & Kavi Dey (Harvey Mudd College) current categorization looking for asteroid dynamical families takes ~30 minutes of computation per asteroid. Vera Rubin observatory will discover 10 million more asteroids. Using machine learning and computationally cheaper asteroid properties to find families. Code is available, but they only gave it as QR code not a link...sigh.
Wait … Harcourt Fenton Mudd conned his way into owning … a *college*??
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As part of the CV-rejiggering for academic stuff that I previously complained about, I also need to update my academic website (which is embarrassingly simple, but at least I didn't write it in 1999 and it doesn't have a dancing-linux-penguin-gif like Some Other Academics). Will be trying to do that while listening to the next set of #DDA2026 talks
@sundogplanets But surely it needs to be sprinkled with goat emoji! WIth a good boy looking after them
️
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Paul Wiegert (U. Western Ontario): finding interstellar meteors is really hard! Lots of meteors are from comets with high-eccentricity orbits, hard to get good enough data to measure meteor pre-impact orbits. There *are* interstellar meteors, just not as many as that Harvard astronomer (who the speaker did not name) seems to think, and none have been conclusively discovered yet.
Good on PW for not naming him. That particular astronomer doesn't need any more promotion.
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Paul Wiegert (U. Western Ontario): finding interstellar meteors is really hard! Lots of meteors are from comets with high-eccentricity orbits, hard to get good enough data to measure meteor pre-impact orbits. There *are* interstellar meteors, just not as many as that Harvard astronomer (who the speaker did not name) seems to think, and none have been conclusively discovered yet.
Apostolos Christou (Armaugh Obs.) this talk title is hilarious "Larger asteroids stay sober, smaller asteroids get drunk"
Wow what a cartoon!
Small asteroids end up with gaussian distributions around the family centre.
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Apostolos Christou (Armaugh Obs.) this talk title is hilarious "Larger asteroids stay sober, smaller asteroids get drunk"
Wow what a cartoon!
Small asteroids end up with gaussian distributions around the family centre.
Daniel Durda (SWRI): Overview talk. The asteroid belt is a fossilized collisional system - the size distribution (particularly waves in size dist) tells us about the past. Dust production is "spikey": lots right after a big collision.
Lots of work on Chicxulub impact, where does debris land? (Back into atmosphere, heating it up, burning everything)
Used Ames gun to smash real meteorites and study dust from them.
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Apostolos Christou (Armaugh Obs.) this talk title is hilarious "Larger asteroids stay sober, smaller asteroids get drunk"
Wow what a cartoon!
Small asteroids end up with gaussian distributions around the family centre.
@sundogplanets we need more scientific illustrations like this
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Daniel Durda (SWRI): Overview talk. The asteroid belt is a fossilized collisional system - the size distribution (particularly waves in size dist) tells us about the past. Dust production is "spikey": lots right after a big collision.
Lots of work on Chicxulub impact, where does debris land? (Back into atmosphere, heating it up, burning everything)
Used Ames gun to smash real meteorites and study dust from them.
I should note that this session (and a at least one other) at #DDA2026 are tributes to Stan Dermott, who wrote the Solar System Dynamics bible, and taught a LOT of students.
I guess I have a 1-degree-removed connection here? The postdoc I first worked with, Beth Holmes, who taught me a lot, when I was a baby undergrad, had just finished her PhD with him. (She died from a heart condition while I was still an undergrad)
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Paul Wiegert (U. Western Ontario): finding interstellar meteors is really hard! Lots of meteors are from comets with high-eccentricity orbits, hard to get good enough data to measure meteor pre-impact orbits. There *are* interstellar meteors, just not as many as that Harvard astronomer (who the speaker did not name) seems to think, and none have been conclusively discovered yet.
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I should note that this session (and a at least one other) at #DDA2026 are tributes to Stan Dermott, who wrote the Solar System Dynamics bible, and taught a LOT of students.
I guess I have a 1-degree-removed connection here? The postdoc I first worked with, Beth Holmes, who taught me a lot, when I was a baby undergrad, had just finished her PhD with him. (She died from a heart condition while I was still an undergrad)
Mark Wyatt (U. of Cambridge) talking about dynamical effects of planets on debris disks (I LOVE this stuff). This is true in our own solar system, zodiacal dust is affected by our planets' orbits.
Ooo Fomalhaut, my favourite disk system! The brightness variations in the disk place constraints on the forced eccentricities resulting from unseen planets in the system.
Fom b is a dust cloud, not a planet, which I am incredibly proud I wrote about years ago! Now proven from JWST images!
