Download Dwarf planets and small solar system bodies

Dwarf planets and small
solar system bodies
NVR mini-symposium
Dwarf planets,
28 October 2015,
Paul Wesselius
Topics described
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Sun and 8 planets
Dwarf planets
Asteroids
Comets
Oort cloud
Kuiper belt
Heliosphere
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Literature, websites
• At the Edge of the Solar System (ESS): Icy New Worlds
Unveiled, Alain Doressoundiram, Emmanuel Lellouch,
Springer Praxis Books, Berlijn, 2009
• Small Bodies in Planetary Systems (Lecture Notes in
Physics), Editors: Ingrid Mann, Akiko Nakamura, and
Tadashi Mukai, Springer, Berlijn, 2009
• A website from Jewitt, the discoverer of the first Kuiper
Belt object after Pluto:
http://www2.ess.ucla.edu/~jewitt/kb.html
• Belgian site with many pictures:
http://www.spacepage.be/artikelen/hetzonnestelsel/dwergplaneten-en-plutoiden
• A site on dwarf planets from Mike Brown:
http://www.mikebrownsplanets.com/
• The mission to Pluto:
http://www.nasa.gov/mission_pages/newhorizons
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http://www.slideshare.net/redcedarmedia/the-sun-the-earth-the-moon
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http://csep10.phys.utk.edu/astr161/lect/solarsys/revolution.html
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http://csep10.phys.utk.edu/astr161/lect/solarsys/revolution.html
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Sideview of the planetary orbits, see:
http://csep10.phys.utk.edu/astr161/lect/solarsys/revolution.ht
ml
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Dwarf planets
Resolution B5 of the IAU*
• A planet is a celestial body that
1. is in orbit around the Sun,
2. has sufficient mass for its self-gravity to overcome rigid
body forces so that it assumes a hydrostatic equilibrium
(nearly round) shape,
3. has cleared the neighborhood around its orbit.
• A "dwarf planet" is a celestial body that
– has the properties 1. and 2. of planets, but
– has not cleared the neighborhood around its orbit, and
– is not a satellite (‘moon’)
• All other objects, except satellites, orbiting the Sun
shall be referred to collectively as "Small Solar
System Bodies"
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IAU = International Astronomical Union
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5 dwarf planets have been recognised so far by the IAU,
http://app.plutosafari.com/articles/guide/definition.html
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Asteroid Belt
Between Mars and
Jupiter there exists a
belt of asteroids (from
2.1 to 3.3 AU*).
In the stable Lagrange
points of the JupiterSun system there are
‘trapped’ asteroids: The
Trojans and the Greeks.
750.000 larger than 1
km, 200 bigger than
100 km diameter.
From: Wikipedia
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1 AU is the distance between the Sun and the Earth = 150 million km
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Near-earth asteroids
Some asteroids can
come close to the
Earth and even hit it.
http://astronomy.swin.
edu.au/cosmos/N/Near
+Earth+Asteroids
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Tsjeljabinsk fireball
On 15 Feb 2013 a fireball appeared, brighter than the Sun.
Detonation energy exceeded the Hiroshima bomb (15 kiloton)
energy by a factor 30  all windows were shattered. Happily such
explosions occur at heights of ~ 8 km.
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Asteroids and comets visited by spacecraft, March 2015 (via:
https://www.reddit.com/user/Tanchistu ). Vesta and Ceres are too
large for this picture)
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Ceres
Ceres, the only
asteroid promoted to
dwarf planet status,
seen by Dawn on 19
Feb 2015.
Sebastiaan de Vet will
tell much more about
it, and about Vesta,
also visited by Dawn.
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A comet
1 to 50 km
nucleus
http://www.wisegeek.org/what-is-the-difference-between-a-comet-and-a-meteor.htm#
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67P/Churyumov-Gerasimenko
http://sci.esa.int/rosetta/14615-comet-67p/
On 12 Nov
2014 Philae
(launched from
the ESA
satellite
Rosetta)
landed on
comet 67P.
The surface is
very hard.
That caused
Philae to
rebound and
hop around.
67P seems to
exist out of
two loosely
connected
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parts
The dashed path is the orbit the comet would follow if it had no Jupiter
encounter. The solid line show the new, smaller elliptical comet orbit after a
close gravitational encounter with Jupiter. These comets are assumed to
originate in the Kuiper Belt, periods < 200 years.
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http://www.astronomy.ohio-state.edu/~pogge/Ast161/Unit4/dance.html
Most newly
discovered
comets are long
period comets.
These originate
from a region
called the Oort
Cloud which
extends to about
50,000 AU from
the Sun. The
comets from this
cloud have very
elongated orbits,
and therefore
spend most of
their time far
from the Sun.
https://lcogt.net/education/article/background-asteroids-comets-and-neos/
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https://lcogt.net
/education/articl
e/backgroundasteroidscomets-andneos/
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The Kuiper Belt (also: Kuiper-Edgeworth Belt) is a disk-shaped region past
the orbit of Neptune. It extends from the orbit of Neptune (30 AU) out to
around 50 AU from the Sun and contains hundreds of millions of small icy
bodies. http://theplanets.org/kuiper-belt/ . Michael Müller tells more.
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The ‘Astronomy Picture of the Day’, 14 September 2015: a digital
composite picture of Pluto, made by the NASA satellite New Horizons.
http://apod.nasa.gov/apod/ap150914.html
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The Heliosphere
Bow
shock
lies at
110 to
160 AU.
Oort
cloud lies
much
farther
out.
http://www.ieap.uni-kiel.de/et/en/ag-heber/forschung/sun-helio.php
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