Orbital resonance — the striking gravitational dance done by planets with aligning orbits

"The newest example of a resonant chain is the HD 110067 system. It’s about 100 light years away and has six sub-Neptune planets, a common type of exoplanet, with orbit ratios of 54:36:24:16:12:9. The discovery is interesting because most resonance chains are unstable and disappear over time. Despite these examples, resonant chains are rare, and only 1% of all planetary systems display them. Astronomers think that planets form in resonance, but small gravitational nudges from passing stars and wandering planets erase the resonance over time. With HD 110067, the resonant chain has survived for billions of years, offering a rare and pristine view of the system as it was when it formed."

This is intriguing. HD 110067 properties can be seen at this site, https://exoplanet.eu/home/

All six orbit well inside where we see Mercury in our solar system with masses ranging 3.9 earth to 8.52 earths. The host star is listed as 8.1 Gyr. Somehow these super earths formed very close to the host star, maintained their orbits and resonance, perhaps over some 8.1 billion years or more. The timescale for the age of the system could also be wrong, not nearly so old.
That's not what I see. It appears to me that each orbit is independent and UN-affected by the other orbits. I didn't see any change in their speed or direction when they grouped up. Or spread apart.

I think we could put a duplicate earth in earth's orbit without any effects at all. And even slowly nudge it to earth and even dock with it, if it didn't spin. Just like satellites.

I even think one could pluck or more planets out and the ones left would continue.

I think a planet orbit is in resonance with itself. One small stretched out spin formed into a another rotation. I think a planet orbit is a one turn closed helix. 1 to 1 ratio.
It has always seemed a little odd to me that the swinging analogy is used to support unchanging (ie stable) orbits. The point in pushing at the right time on the swing is to cause the person to go higher and higher and higher....

I think in most cases, resonance is destabilizing. This, apparently, is very true for small bodies orbiting a large one, like ring particles around Saturn. The gaps found in the asteroid belt are other examples.

But when it's more massive objects, the resonance serves to hold them from wandering. Funny how the same forces of nature can, in certain cases, produce opposite results.
The animation is of too small a scale to show the perturbations that keep them in their stable orbits. Note the fixed rendezvous points. If a planet is slightly early, the other won't be in place yet, the two will be farther away than usual, the early arriver will receive a slight pull to slow it down. When a late arriver gets into position, the other planet will be ahead in its orbit, pulling the laggard ahead.
  • Like
Reactions: rod
My (new) way of conceptualizing gravity is with space as the orthogonal foundation and gravity describes the eccentric distribution of time-speed across it.

Time runs slower proximate to matter, which would be the definition of mass.
Inertia favors slowed time because conceptually either a moving object (matter) 'speeds up' or space 'shrinks' in the vicinity of slowed time.

Planets in resonance are temporally slipstreaming.
Aligning in a temporal trough not a spatial one.

Depending on the distance between planets, planet sizes and the distance to their star they might be in a constant eclipse state except for the innermost planet. Constantly in the shade of another planet(s).

Also people/beings on middle planets quite possibly can see only the two planets they are between because any planet further from them in the sequence are in constant occultation.

Hard to imagine this wouldn't be a problem keeping an orbiting moon in orbit unless it was perfectly perpendicular to planet chain axis.
Otherwise it would constantly be hitting temporal 'speed bumps'.
There are 894 solar systems documented now at this site, https://exoplanet.eu/catalog/, and 947 documented here, https://exoplanetarchive.ipac.caltech.edu/index.html

None of these solar systems look like ours here. HD 11067 system is also found in my queries, TRAPPIST-1 too, and others like KOI-351 with 8 planets., also Kepler-90. Others have 2 or more exoplanets confirmed now. I would think astrobiology needs to show some of these extra-solar systems, indeed have an earthlike exoplanet with life on it, whether microorganisms or planets and trees. K2-18 system shows up and there are a number of reports attempting to show life on this possible hycean world. Others keep popping up indicating a magma world is likely here and not phytoplankton swimming around in a habitable ocean world.

JWST data suggest exoplanet K2-18b may have molten surface rather than a watery ocean, https://phys.org/news/2024-02-jwst-exoplanet-k2-18b-molten.html

Ref - Distinguishing Oceans of Water from Magma on Mini-Neptune K2-18b, https://iopscience.iop.org/article/10.3847/2041-8213/ad206e, 02-Feb-2024. "Abstract Mildly irradiated mini-Neptunes have densities potentially consistent with them hosting substantial liquid-water oceans ("Hycean" planets). The presence of CO2 and simultaneous absence of ammonia (NH3) in their atmospheres has been proposed as a fingerprint of such worlds. JWST observations of K2-18b, the archetypal Hycean, have found the presence of CO2 and the depletion of NH3 to <100 ppm; hence, it has been inferred that this planet may host liquid-water oceans. In contrast, climate modeling suggests that many of these mini-Neptunes, including K2-18b, may likely be too hot to host liquid water. We propose a solution to this discrepancy between observation and climate modeling by investigating the effect of a magma ocean on the atmospheric chemistry of mini-Neptunes. We demonstrate that atmospheric NH3 depletion is a natural consequence of the high solubility of nitrogen species in magma at reducing conditions; precisely the conditions prevailing where a thick hydrogen envelope is in communication with a molten planetary surface. The magma ocean model reproduces the present JWST spectrum of K2-18b to ≲3σ, suggesting this is as credible an explanation for current observations as the planet hosting a liquid-water ocean."

Still looking for ET phoning home :)
  • Like
Reactions: Helio and billslugg

Latest posts