Caption:
Collage
to-scale insofar as that is known
for 8 of the brightest
trans-Neptunian objects (TNOs):
Pluto,
Eris,
Makemake,
Haumea,
Sedna,
Gonggong (AKA 2007_OR_10),
Quaoar,
Orcus
and their known moons.
The Earth
also to-scale is shown
for size comparison.
Features:
- The Earth,
Pluto,
and Charon are
real images.
The others are artist's conceptions
since the astronomical objects
CANNOT be imaged.
- For the unimaged
astronomical objects,
their sizes are probably all estimated from their
H magnitude
and estimated albedos.
Note the
brightest TNOs
are easiest to discover because they are
brightest TNOs.
- Five
of the shown
TNOs have
moons and these are also
are also shown in the collage in
artist's conception.
- Since Quaoar and
Orcus have
moons, it is known
from Newtonian physics that
Quaoar is much more massive than
Orcus.
- The top 4
TNOs shown
are accepted by the
International Astronomical Union (IAU)
as dwarf planets while the bottom
4 shown are
dwarf-planet candidates
that are accepted as dwarf planets by
several astronomers
(see Wikipedia:
Dwarf planet: Population of dwarf planets).
- Eris
(discovered 2005
Jan05 by
Mike Brown (1965--) et al.) was the
TNO that
killed Pluto's
planet status.
It was clear that eventually we'd likely find more
TNOs
larger than
Pluto and that if we left
Pluto a planet,
we'd soon have planets coming out of ears---and the
whole class of planets would become degraded.
The discovery of Eris made
the problem palpable, and so Pluto had to
go in the dwarf planet class.
- The dwarf planet class may NOT
last.
It's too hard to know what
astronomical objects fall into it
as evidenced by the long list of
dwarf-planet candidates
(see Wikipedia:
List of possible dwarf planets).
We may well just call
former dwarf planets
large asteroids,
large TNOs, etc.
- See Trans-Neptunian object keywords
below
(local link /
general link: trans_neptunian_objects_keywords.html):
php require("/home/jeffery/public_html/astro/solar_system/trans_neptunian_objects_keywords.html");?>
Credit/Permission: ©
User:Lexicon,
2006,
User:Aineias,
2015 /
Creative Commons
CC BY-SA 3.0.
Image link: Wikipedia:
File:EightTNOs.png.
Local file: local link: trans_neptunian_objects_collage.html.
File: Solar System file:
trans_neptunian_objects_collage.html.