Trans Neptunian Objects TNOs - Agreed Terms - May 2022

Catastrophe

"There never was a good war, or a bad peace."
Trans Neptunian Objects (TNOs) comprise a number of different category objects crossing or beyond the orbit of Neptune, and frequently overlapping in description. Note that Comets and Centaurs are not included. Great diagrams courtesy Wiki. Note that by pressing the . . . option and selecting, then clicking, Download, the image may be enlarged considerably.

View: https://imgur.com/a/beaINhn

Note that the only TNOs shown are categorised as Kuiper Belt Objects or Scattered Disk Objects. Other categories will be discussed. Note: Centaurs are excluded.

The largest TNOs currently known (2022) are smaller than Earth’s Moon:

View: https://imgur.com/a/K31BOiw

Kuiper Belt Objects

The Kuiper Belt begins approximately at the orbit of Neptune at 30 AU, and extends to around 50 AU. Some suggest further.

View: Https://imgur.com/a/Yr6YA6P


Orbits shown are of Neptune and Pluto. Image would be as seen from several hundred AU beyond Sun. No other TNOs shown.


Kuiper Belt Objects include some Dwarf Planets, such as Pluto,

Kuiper Belt Objects: Facts about the Kuiper Belt & KBOs | Space

Formation of Kuiper Belt
“When the solar system formed, much of the gas, dust and rocks pulled together to form the sun and planets. The planets then swept most of the remaining debris into the sun or out of the solar system. But objects at the edge of the solar system were far enough away to avoid the gravitational tugs of the much larger planets like Jupiter, and so managed to stay in their place as they slowly orbited the sun. The Kuiper Belt and its compatriot, the more distant and spherical Oort Cloud, contain the leftover remnants from the beginning of the solar system and can provide valuable insights into its birth.”



Some prominent KBOs:

Pluto
Former planet, now designated Dwarf Planet, along with its largest Moon (or co-Dwarf Planet) Charon.

2004 DW All indications are that it is a “Plutino” – that is a KBO in orbit very similar to Pluto’s: Pluto goes around the Sun twice for every 3 times that Neptune goes around the Sun.
50000 Quaoar Dwarf Planet, about half the diameter of Pluto.

20000 Varuna The red color of Varuna's surface results from the photolysis of organic compounds being irradiated by sunlight and cosmic rays.

2000 WR106 One of the brightest known Trans-Neptunian Objects other than Pluto and its satellite Charon.

2002 AW197 the largest unnamed object in the Solar System. Possibly a cunewano. Cubewanos have orbits with semi-major axes in the 40–50 AU range and, unlike Pluto, do not cross Neptune's orbit. That is, they have low-eccentricity and sometimes low-inclination orbits like the classical planets.
The name "cubewano" derives from the first trans-Neptunian object (TNO) found after Pluto and Charon, and labelled QB1. Other similar objects sunsequently labelled “cu be one o’s”.

55636 = 2002 TX300 It is a large member of the Haumea family that was discovered on 15 October 2002 by the Near-Earth Asteroid Tracking (NEAT) program.
28979 Ixion

2001 KX76 Virtual Telescope Observes Record-Breaking Asteroid - New data show that '2001 KX76' is larger than Ceres | ESA/Hubble (esahubble.org)

1999 CL119 1999 CL119 is a large trans-Neptunian object in the Kuiper Belt, classified as an extended Scattered Disk Object (DO) or Cubewano (CKBO) in terms of orbit dynamics. Due to its size, the asteroid may be one of the dwarf planet candidates.


15760 Albion It is a "cold" classical Kuiper belt object and gave rise to the name cubewano for this kind of object, after the QB1 portion of its designation.

Classical Kuiper Belt Objects

Classical Kuiper Belt Objects (ucla.edu)


Classical KBOs are those having orbits with modest eccentricities and semimajor axes roughly in the 40 to 47 AU range. They are defined as a group by their long-term stability - they simply never approach Neptune closely enough to have been ejected over the age of the Solar system.

Dwarf Planets

Dwarf planets are defined by size, not by location. However, apart from Ceres, which is in the Asteroid Belt, they seem (according to current thinking) to be in the Kuiper Belt.

Astronomers estimate that there could be as many as 200 dwarf planets in the solar system and the Kuiper Belt.
www.space.com/15216-dwarf-planets-facts-solar-system-sdcmp.html

Dwarf planet - Wikipedia
https://en.wikipedia.org › wiki › Dwarf_planet


A dwarf planet is a small planetary-mass object that is in direct orbit of the Sun – something smaller than any of the eight classical planets, ...
List of possible dwarf planets · ‎Ceres · ‎Eris · ‎Makemake

Apart from Sedna, the largest ten of these candidates have either been visited by spacecraft (Pluto and Ceres) or have at least one known moon (Pluto, Eris, Haumea, Makemake, Gonggong, Quaoar, Orcus, and Salacia), which allows their masses and thus an estimate of their densities to be determined.
For nearly all of its orbit, Sedna is even farther from the Sun than at present: its orbit is one of the largest in the Solar System other than those of long-period comets, with its aphelion estimated at 937 AU.


Plutinos (Plutoids)

The Plutinos, shown in the inner belt of the Kuiper Belt, are a type of resonant object.

Plutinos are a dynamical group of trans-Neptunian objects that orbit in 2:3 mean-motion resonance with Neptune. This means that for every two orbits a plutino makes, Neptune orbits three times. The dwarf planet Pluto is the largest member as well as the namesake of this group. The next largest members are Orcus, (208996) 2003 AZ84, and Ixion. Plutinos are named after mythological creatures associated with the underworld.
Plutinos form the inner part of the Kuiper belt and represent about a quarter of the known Kuiper belt objects.
They are shown in red to the left (inner) side of the Kuiper Belt.
Other resonant objects are found in outer areas of the Solar System:

Orbital resonance - Wikipedia
 
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Catastrophe

"There never was a good war, or a bad peace."
Scattered Disk Objects

"Scattered disk objects are Kuiper Belt Objects (KBOs) with large orbital eccentricities. They have perihelia between 30 and 48 AU, aphelia greater than 60 AU"

"The Scattered Disc (or Disk) is the name given to a collection of small, icy objects out in the far reaches of the Solar System. It begins at the outer edge of the Kuiper Belt (at about 2,800 million miles from the Sun) and extends as far out as 10,000 million miles."

"The scattered disc (or scattered disk) is a distant region of our solar system, thinly populated by icy minor planets known as scattered disc objects (SDOs), a subset of the broader family of trans-Neptunian objects (TNOs). The innermost portion of the scattered disc overlaps with the Kuiper belt, but its outer limits extend much farther away from the Sun and above and below the ecliptic than the belt proper."


View: https://imgur.com/a/7v3j9er

Note: 2000 AU = 0.03162501 light years.




Scattered Disk Objects | COSMOS - Centre for Astrophysics ...
https://astronomy.swin.edu.au › cosmos › scattered+dis...


Scattered disk objects are Kuiper Belt Objects (KBOs) with large orbital eccentricities. They have perihelia between 30 and 48 AU, aphelia greater than 60 ...

The Scattered Disc - objects at the boundary of the Solar System
https://www.guide-to-the-universe.com › the-scattered-...


The Scattered Disc (or Disk) is the name given to a collection of small, icy objects out in the far reaches of the Solar System. It begins at the outer edge ...
You visited this page on 27/03/22.

Scattered disc | Space Wiki
https://space.fandom.com › wiki › Scattered_disc


Detached objects, or an extended scattered disc? — The scattered disc (or scattered disk) is a distant region of our solar system, thinly populated ...










Work in progress. Last Edit 14 May 2022 15.30 BST.
 
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Catastrophe

"There never was a good war, or a bad peace."
Thanks, Helio. This is meant to be a major differentiation, so I am trying to summarise the different constituents, and what you say, is what I am aiming for. Each division will have its separate section, so this is just meant to summarise, but with enough information to separate the 'chunks of rock' I will keep foremost in my mind what you suggest. They all consist of chunks of (icy) rock, so positional (geographical ~ astrographical?) division is foremost.

An extreme example is dwarf planets. All, except Ceres, are beyond Neptune, and in the Kuiper Belt, but Sedna has an extreme aphelion. Of course, there is the differentiation by size. Beyond that, for example - you have the Plutinos (or Plutoids) in the inner Kuiper Belt, but differentiated by resonance. Others much further out, and also exhibit resonance. Cubewanos classical KBOs beyond Neptune, with low eccentricity but not exhibiting resonance. Lots of subdivisions with different differentiating criteria.
Just look at this:
"1999 CL119 1999 CL119 is a large trans-Neptunian object in the Kuiper Belt, classified as an extended Scattered Disk Object (DO) or Cubewano (CKBO) in terms of orbit dynamics. Due to its size, the asteroid may be one of the dwarf planet candidates." See what I mean?

Thank you for your constructive comment - always very welcome. You have given me the idea to also put such a short summary at the end. Please pardon the split infinitive!


Cat :)

P.S. I have done some editing on the pre-SDO section - what do you think?
 
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