New physics or vanishing planets?

schlowi123

S
In connection with the Hunt for Trojans (and Greeks) CMDR Orvidius has made one of his famous lists that include a subset of said co-orbiting planets.

The interesting thing is now, that he also discovered co-orbiting planets with a difference in the argument of periapsis of 120 degrees!!!

In principle this is possible. Planets at Lagrange points L4 and L5 are 120 degrees separated from each other. But that would require an "anchor"-planet in the middle.
However, there are planets in the ED galaxy that are 120 degrees much apart in the same orbit but WITHOUT an anchor-planet to which they belong.

These systems and planets are
Iockols EG-Y g5 planets 3 and 4
Phipoea BG-O e6-3301 planets 13 and 14
Dryoea Prue AA-A h8 planets AB 5 and AB 6
Prae Drye QE-F d12-24 planets 7 and 8
Thaile FG-G c13-12 planets 3 and 4
Dryao Aoscs HR-W e1-10126 planets 6 and 7
Scaulua AW-V e2-23 planets 7 and 8
Hypio Gree AA-A h100 planets 12 and 13

There are probably more but so far these are the only ones I found.
If any commanders are close to these systems, would they please check out what's going on there and post an Orrery picture here.

In the name of science!
 

Sapyx

Sapyx
I suspect many of them are simply a case of "incomplete scanning".

Example: the first one in your list, Iockols EG-Y g5. The EDSM page for this system currently shows planet 1, then planets 3,4, 5, 6, 8 and 9a... planet number 2 is missing (as well as planets 7 and 9, and maybe more). I would assume that whoever scanned this system back in the pre-FSS days cherry-picked the MRs and HMCs but didn't bother scanning most of the gas giants (or secondary stars).

Which means that planet 2 is acting as anchor for two Trojan planets.
 
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Orvidius

Orvidius
That would be a pretty solid explanation. I'm also not ruling out StellarForge sometimes getting a bit weird with its math too. I think it's still possible for the periapsis to be outside of 60 degrees as long as the Mean Anomaly makes up for it. Unless I'm misunderstanding my orbital mechanics again (KSP has given me a good intuitive understanding, but I rarely attempt any math on it).
 

schlowi123

S
I've checked my own data and on EDSM for possible anchors and have some more information.

Phipoea BG-O e6-3301 may be a real 120-degrees-trojan-system because all possible anchor planets are not in the right distance (or don't exist at all).

Dryoea Prue AA-A h8 may have an anchor but I can't see it from the EDSM data since the planets don't orbit the main star (and thus the distance to arrival can be different even though the orbital parameters fit trojan parameters).

In Iockols EG-Y planet two could be an anchor. Unfortunately it is not available in the data.


For the following systems binary systems could act as an anhor. But than the naming "convention" really confuses me. So these are likely greeks and trojans at the L4 / L5 points.
  • Prae Drye QE-F d12-24 (with planets 5 + 6 as the binary system)
  • Thaile FG-G c13-12 (with planets 1 + 2 as the binary system)
  • Dryao Aoscs HR-W e1-10126 (with planets 4 + 5 as the binary system)
  • Scaulua AW-V e2-23 (with bodies 5 + 6 as the binary system). This is the system that made me aware of this.
  • Hypio Gree AA-A h100 (with bodies 10 + 11 as the binary system)

So … well … it seems that there is no new physics after all (except maybe Phipoea BG-O e6-3301). :(

I apologize for the fuzz. I was just so excited about the results. Should have checked that beforehand.

Damn! Science is hard. :(
 

schlowi123

S
Ah yes … the audience came to the same conclusion.

That means, that the number of trojans may be far higher than any of the algorithms can detect. But that was expected. And it's probably still low compared to the number of systems.

My second algorithm could in principle detect those (that's how I got aware of them in the first place), but than I have to increase the allowed difference in distance to arrival. This however would greatly increase the number of false positives :(
 

Maolagin

M
Fascinating analysis, good work!

One additional possibility I would raise: since on astronomical timescales our experience of the galaxy is a snapshot in time, it is possible (likely even, presuming Stellar Forge works this way) to find systems that are in an unstable state. The obvious example is extremely close binary planets, where you can calculate that the binaries would collide and merge in much less than the age of the parent star. Very quickly in cosmic terms, but still thousands or millions of years from today.

In the case of these far-from-60° pairs, some of them could plausibly be bodies in Horseshoe orbits caught partway through their cycle. Hard to confirm unfortunately. As far as we know, once Stellar Forge finishes generating a system, the bodies are stuck on ideal Keplerian orbits forever. In a real horseshoe-type orbit we'd see the offset angle and other orbital parameters evolve slightly from year to year. In our situation that will never happen though; the bodies are fixed in their current arrangement.
 

ReggieN0ble

R
for sure. here are 2 orrery screenshots, but i think this one is not a trojan system :(
myumbao aa-a h127, AB3 + AB4

if you have some other systems to check near the core send me a list and i can visit some systems. i am sick of scanning aa-a h systems and need a break.
 

Eahlstan

E
ReggieN0ble said:
for sure. here are 2 orrery screenshots, but i think this one is not a trojan system :(
myumbao aa-a h127, AB3 + AB4

if you have some other systems to check near the core send me a list and i can visit some systems. i am sick of scanning aa-a h systems and need a break.
Click to expand...

I have 6 AA-A H systems left in DRYOEA BLUE, after these I take a AA-A H break too and check the systems I've been given - minus the one you discovered 🙃
 

schlowi123

S
Thank you very much :) Unfortunately I can't see the imgur images (have blocked it on my PC's because I tend to waste too much time there). So that has to wait until I'm somewhere else.
 

Eros

Eros
Orvidius said:
That would be a pretty solid explanation. I'm also not ruling out StellarForge sometimes getting a bit weird with its math too. I think it's still possible for the periapsis to be outside of 60 degrees as long as the Mean Anomaly makes up for it. Unless I'm misunderstanding my orbital mechanics again (KSP has given me a good intuitive understanding, but I rarely attempt any math on it).
Click to expand...

Looking into the Maths a bit, the best representation of the stable points is to draw out the Roche potential. For a system with a central heavy object such as a star, and a smaller object orbiting it, the ratio of mass is very large and you are completely correct in that such a system gives a region of stability more than just a singular point. Looking at Trojan asteroids of Jupiter you can observe a rather huge spread in objects around L4 and L5 Lagrange points. Id easily say eyeballing it that you probably expect 60+/- 5 easily.

Also note that for binary stars, the L4 and L5 points can actually be very different to 60 degrees and will be at 90degrees for object of equal mass.
 

malenfant

M
It's kinda frustrating that your algorithm can't predict trojans, only find them in existing data. The thing I hate about exploring in ED is that it's just rolling dice and seeing what you get, I'd love it if there was actually some kind of predictive logic we could apply (beyond mass codes) so we could actually go searching for stuff and doing some actual, proper exploring.
 

schlowi123

S
Well that IS possible, though probably not with trojans.
But (I think) CMDR marx did that with ELW's and I think if you apply the knowledge he figured out you can boost your rate to find ELW's by one order of magnitude (which is impressive).
 

Sapyx

Sapyx
malenfant said:
It's kinda frustrating that your algorithm can't predict trojans, only find them in existing data. The thing I hate about exploring in ED is that it's just rolling dice and seeing what you get, I'd love it if there was actually some kind of predictive logic we could apply (beyond mass codes) so we could actually go searching for stuff and doing some actual, proper exploring.
Click to expand...

To be fair, both real-world exploring and stereotypical sci-fi exploring is pretty much like this. "Boldly going", and all that. The only possibility I can imagine, beyond blindly jumping into an unexplored star system and seeing what's there, is to have some kind of long-range scanner that lets you scan stars within, say, 10 LY, to remotely detect the presence of objects of interest, like aline signals, ELWs or such. For Trojans, you'd want to be searching for systems with gas giants (since I'm sure 99% of all trojan anchor planets are gas giants). However, this method of "exploring" might not sit well with the "traditional" jump-in-and-look explorers who look down upon "armchair explorers", who explore by cruising around the galaxy map, as lazy.
 

malenfant

M
I mean to be fair the galaxy map is really the problem - the search functionality is practically non-existent (it's impossible to search through or isolate most of the information provided) and it's impossible to plan multi-stop routes in it. Without that there's little else to do but 'explore aimlessly' anyway, but Frontier don't seem interested in doing anything to fix that.
 
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