Comet gateway discovered to inner solar system, may alter fundamental understanding of comet evolution

**Comet gateway discovered to inner solar system, may alter fundamental understanding of comet evolution
An artist rendered image of what Centaur SW1 would look like as an inner solar system Jupiter-Family comet at a distance of 0.2 AU (30 million km, 19 million miles) from Earth. The Moon is in the upper right part of the frame for scale. Credit: University of Arizona/Heather Roper

A new study led by a University of Central Florida researcher may fundamentally alter our understanding of how comets arrive from the outskirts of the solar system and are funneled to the inner solar system coming closer to Earth.

In a study to be published in the Astrophysical Journal Letters this week, scientist Gal Sarid and co-authors describe the discovery of an orbital "gateway" through which many comets pass before they approach our sun. The gateway was uncovered as part of a simulation of centaurs, small icy bodies traveling on chaotic orbits between Jupiter and Neptune. The study team modeled the evolution of bodies from beyond Neptune's , through the giant planet's region, and inside Jupiter's orbit. These icy bodies are considered nearly pristine remnants of material from the birth of our solar system.

For a long time, the pathway of comets from their original formation location inward toward the sun has been debated.

"How do new comets, controlled by Jupiter's influence, replace those that are lost? Where is the transition between residing in the outer solar system, as small dormant bodies, and becoming active inner solar system bodies, exhibiting a widespread gas and dust coma and tail?" asks Sarid, the lead scientist for the study. These questions remained a mystery until now. "What we discovered, the gateway model as a 'cradle of comets,' will change the way we think about the history of icy bodies," he says.

Centaurs are thought to originate in the Kuiper Belt region beyond Neptune and are considered as the source of Jupiter Family Comets, which occupy the inner solar system. The chaotic nature of orbits obscures their exact pathways making it difficult to predict their future as comets. When icy bodies such as centaurs or comets approach the sun, they begin to release gas and dust to produce the fuzzy appearance of the coma and extended tails that we refer to as comets. This display is among the most impressive phenomena observable in the night sky, but it is also a fleeting flicker of beauty that is rapidly followed by either the destruction of the comet or its evolution to a dormant state, Sarid says.

The original goal of the investigation was to explore the history of a peculiar centaur– 29P/Schwassmann-Wachmann 1 (SW1), a mid-sized centaur in a nearly circular orbit just beyond Jupiter. SW1 has long puzzled astronomers with its high activity and frequent explosive outbursts that occur at a distance from the sun where ice should not effectively vaporize. Both its orbit and activity put SW1 in an evolutionary middle ground between the other centaurs and the Jupiter Family Comets. The research team wanted to explore whether SW1's circumstances were consistent with the orbital progression of the other centaurs, Sarid says.

"More than one in five centaurs that we tracked were found to enter an orbit similar to that of SW1 at some point in their lifetime," said Maria Womack, a Florida Space Institute scientist and co-author of the study. "Rather than being a peculiar outlier, SW1 is a centaur caught in the act of dynamically evolving into a JFC." In addition to the commonplace nature of SW1's orbit, the simulations lead to an even more surprising discovery, Womack says.

"Centaurs passing through this region are the source of more than two thirds of all JFCs, making this the primary gateway through which these comets are produced," says Womack. The Gateway region does not hold resident objects for long, with most centaurs becoming JFCs within a few thousand years. This is a short portion of any solar system object's lifetime, which can span millions and sometimes billions of years.

The presence of the gateway provides a long sought-after means of identifying the centaurs on an imminent trajectory toward the inner solar system. SW1 is currently the largest and most active of the handful of objects discovered in this gateway region, which makes it a "prime candidate to advance our knowledge of the orbital and physical transitions that shape the population we see today," Sarid says.

Our understanding of comets is intimately linked to knowing our solar system's early composition and the evolution of conditions for atmospheres and life to arise, the researchers said.


Explore further

NASA's Wise finds mysterious centaurs may be comets

More information: Gal Sarid, et al. 29P/Schwassmann-Wachmann 1, A Centaur in the Gateway to the Jupiter-Family Comets. arXiv:1908.04185v2 [astro-ph.EP]: arxiv.org/abs/1908.04185
Journal information: Astrophysical Journal Letters

Citation: Comet gateway discovered to inner solar system, may alter fundamental understanding of comet evolution (2019, September 20) retrieved 20 October 2019 from https://phys.org/news/2019-09-comet-gateway-solar-fundamental-evolution.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
1550 shares

Feedback to editors

User comments

Sep 20, 2019
if i am correctly understanding this supposition of "gateways" for comets?
& wouldn't this also hold true for asteroidal bodies & general debris?

the first thought that came to my mind?
"aren't these Lagrange points?"

so? is there a reason for calling these Outer System gravitational nodes "gateways" instead of Lagrange points?

did i muss an explanation?
or,
perhaps there is some important difference i am failing to grasp?

Sep 22, 2019
perhaps there is some important difference i am failing to grasp?
There's a great deal you fail to grasp, and not just in connection with comets and orbits and Lagrange points, if your previous posts on PO are any guide.

Just read the article, which explains that:

1) "centaurs" occupy chaotic orbits between Jupiter and Neptune, and
2) SW1 occupies "a nearly circular orbit just beyond Jupiter", and
3) JFC orbits are confined to the inner solar system.

The article never mentions "nodes", as you have done: it mentions orbits and families of orbits within the solar system. So, there are no "nodes" in this discussion, and hence no Lagrange points need to be mentioned or considered here.

You're also confusing "supposition" with scientific discovery based on sound analysis of data.

Do try to stay on track - pun intended...

Sep 23, 2019
sky. ouch!
but, thank you for cluing me in

in the synopsis i found
"we have identified a short-lived dynamical Gateway, a temporary low-eccentricity region exterior to Jupiter through which the majority of JFCs pass."

so, evidently there is a difference
now i will gave to squeeze out the time to read the original paper, if publivly available

cause, honestly, these are new terms & concepts to me
this old dog ain't keeping up with the newest research

Sep 23, 2019
in the synopsis i found "we have identified a short-lived dynamical Gateway, a temporary low-eccentricity region exterior to Jupiter through which the majority of JFCs pass."
Yes indeed, and as they mention further down in that abstract
Currently, the most notable occupant of the Gateway region is 29P/Schwassmann-Wachmann 1 (SW1)
So, the idea is that comets work their way inwards from the outer solar system (probably the Kuiper Belt) to first spend time as "centaurs" in orbits between Neptune and Jupiter, which are "dominated by chaotic gravitational perturbations", gradually work their way inwards to briefly (50 years or so) occupy the low-eccentricity orbit just outside that of Jupiter which they have called a Gateway, and then subsequently move further inwards to occupy eccentric orbits in the inner solar system between Jupiter and the Sun.

This gradual process is driven mainly by gravitational interactions between the comets, the major planets and the Sun

Sep 23, 2019
PS - the full paper can be read here: https://arxiv.org...4185.pdf

Sep 23, 2019
thanks sky for the link
i'll start reading it as prior commits permit

i never realized there were these differences between the centaurs & the trojans
(besides in mythology)

it is interesting that two of my favorite subjects
stochastic influences
& gravitational attraction
are covered ib this research

i relish these research papers provide some confirmation for my speculations about the possibility of ephemeris gravitational influence

during the debates over whether ʻOumuamua was an asteroid, a comet or an alien craft

all those people insisting that the Big O was an asteroid with invisible outgassing
or, a comet with an invisible coma & invisible tail
or an alien craft
with invisible jet exhaust plumes

my absolute favorite?
ʻOumuamua was being pulled
& steered by an invisible sail

but no explain of how that even works!
perhaps they should "reflect" on that?

i'd never realized so many people putting the hate to gravity
i guess they fall down a lot?

Sep 24, 2019
i never realized there were these differences between the centaurs & the trojans
The Trojans are a different set of objects entirely. They are a group of asteroids which share Jupiter's orbit, and which gather in two diffuse groups, centered around the Jupiter-Sun Lagrange points L4 and L5. They have nothing to do with the centaurs.

Different theories seek to explain their origin - among these are:
1) they were formed from material that existed in the same part of the solar sytem as Jupiter;
2) they were already formed and were captured as the giant planets migrated, according to one particular model of solar system formation.

my speculations about the possibility of ephemeris gravitational influence
An ephemeris is a mathematical construct which enables the position of an object - planet, comet, satellite, etc. to be calculated. It is not a physical object, and hence cannot exert a gravitational influence on anything.

Sep 24, 2019
ahh sky, thanks for the explanations

as for my phrasing of "about the possibility of ephemeris gravitational influence"

perhaps i was being too succinct?
& shorthand my thinking

my meaning is, that as the Big O traversed through our Solar System?
in addition to the gravitational pull of our Sun
there were additional random tugging from the planets
though at barely measurable levels
that could explain the tiny inconsistencies claimed to have been observed in ʻOumuamua's velocity & trajectory

i hope this correction in terminology will clarify my speculations

Sep 24, 2019
there were additional random tugging from the planets though at barely measurable levels
that could explain the tiny inconsistencies claimed to have been observed in ʻOumuamua's velocity & trajectory
Do you really imagine that such forces had not been factored into the calculations made of ʻOumuamua's trajectory. Really?

Such things are absolutely standard when dealing with trajectories within the solar system, especially the influence of Jupiter, with smaller contributions from Saturn and the outer giant planets. But these influences do not fluctuate chaotically and are not at all "random", but are rather smoothly changing as a body traverses the solar system.

It's all down to Newton's law of universal gravitaion, F = M1 * M2 / R^2, so these forces depend inversely on the square of the distance between 2 bodies.

The inconsistencies which have been observed in ʻOumuamua's path must be down to something local to that object, maybe outgassing... Who knows?

Sep 24, 2019
yes sky, your last commentary seems to be exact & correct...

...when you are discussing the confirmed & verified, peer-reviewed knowledge
with other reasoning, rational, scientifically-trained people

however, out here in the fantasy world of the internet?
are swarms of fraudulent woomongers,
agitpropers for ignorant piety.
outright crazed loons.
polemic-driven altright deniers of reality such as the antivaxxers
are paid saboteurs attacking real sciences & scientists

"Make America KKKTaliban Again"

sky, if you go back in the archives to when ʻOumuamua was accidentally discovered on it's way out of the Solar System?

& check out the popular press?
many commentators ferociously denounced gravitational influence

with only the tiniest suggestion that there possibly was some extra influence on ʻOumuamua's course & velocity?

cranks violently raved that each wild speculation had to be true
until the next fantasy headline

if you were spared that dubious frenzy of belief?
lucky you!

Sep 25, 2019
if you were spared that dubious frenzy of belief? lucky you!
I know the difference between scientifically acquired facts, and wild speculation, and steer well clear of the latter. Anybody foolish or ignorant enough to be swept up and carried along by idle gossip or frenzied polemic deserves everything they get. Luck has nothing to do with it.

Science, the raison d'être of this site, provides the means by which objective truth may be ascertained. What one does with such truth is "the mark of the man."

Sep 25, 2019
nice to be able to work with sane, informed peers

i am a Humanist ideologue myself

today in the comments on another article
a denierbot was agitproping misinformation about Freeman Dyson

these disgusting displays of fraudulent claims
that are blatant attacks against real science & real scientists
need to be called out to be excoriated as they deserve

or the gullible will mistaken their steershit for truth
& repeat the fakirs lies to other uninformed people

these bunco-artists & looneytoons are a contagion of disease-bearing vermin

i have had a lot of dirty jobs in my life
& it doesn't bother me to confront quislings & frauds
their poison needs to be drained

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more