Transcript Evolution of the Solar System

Evolution of the
Solar System
Matt Rogers
AT350
9 September 2003
Overview

Evolution of a star
Interstellar Nebula
 Formation of protostar and protostellar
nebula
 Evolution of early sequences and
dissipation of protostellar nebula

Overview (continued)

Evolution of planets
Protostellar nebula makeup
 Evolution of protostellar nebula
 Formation of planetisimals

Terrestrial Planets
 Jovian Planets


Endgame
Interplanetary Nebula
Protostars and Protostellar
Nebulae
Accretion of nebular
gases form protostar
Protostar starts
sucking in nearby
nebular gases, forms
local increase in
nebular gas amount –
we call this a
protostellar nebula
A Star Is Born
Protostar continues accreting mass,
becomes more and more massive
 Fusion process in star core initiates
 Increase in solar wind blows protostellar
nebula away (but not planets)
 Star enters main sequence

Protostellar Nebulae and You:
How Planets Are Formed
Mostly H and He, with
other interesting
elements (but nothing
heavier than Iron)
 Depending on
protostellar nebula
temperatures, can
combine to form other
molecules – carbon
dioxide, water,
hydrocarbons, even
rocks!

Protostellar Nebulae and You:
How Planets Are Formed
Near hot protostar, only
rocks accrete – too hot
for hydrocarbon/water
ices
 Outside of the frost line,
both rocks and solid
ices form
 Composition of
planetesimals depends
on where you are in
regards to the frost line

Formation of terrestrial
planetesimals

Chunks of rock orbiting the protostar slam into each
other, form rudimentary planets, called
planetesimals

Planetesimals contain rocks and heavy gases such
as water vapor, CO2, nitrogen, etc., with a
rudimentary H and He atmosphere
Formation of Jovian
planetesimals



Planetesimals similar to
terrestrial variety, except
that they grow faster, since
they’re accreting rocks and
solid ices
Become massive more
rapidly, eventually become
large enough to capture H
and He from the surrounding
nebula (if it’s dense enough)
– this is how gas giants are
formed
If there’s not enough nebular
gas (i.e. a long way from
the sun) the small
planetesimals remain as
comets
Final Stages

Nebular gas ejected from solar system, planets
remain and begin to cool
The Early Earth



Earth cools (having lost
early H and He
atmosphere), begins
outgassing water, cabon
dioxide and nitrogen
gas
Early oxygen released
from silicate materials,
bulk from
photosynthesis later
From here on out, just
like in the notes!
Fin.