ABOUT THE MIDTERM F2015 R… · Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015 About the Midterm • KEY ideas: • Terrestrial planet characteristics vs. Jovian

ABOUT THE MIDTERM

Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015

About the Midterm

• Same “rules”

• Use your index card!

• About the same length/structure

• Objects in the Solar System through Stars & Galaxy Classification

• roughly 33% Solar System topics & 67% Stellar & Galaxy topics


About the Midterm

• KEY ideas:

• Terrestrial planet characteristics vs. Jovian planet characteristics

• Mars and water on Mars (importance of magnetic fields)

• Venus & Venus’ temperature

• Greenhouse effect/Climate Change

• Saturn’s rings, Jupiter’s “weather”, Io, Ganymede, Callisto, Europa, Titan & Enceladus

• Distances to stars: parallax & standard candles

• Temperature & Color and Temperature & Size & Luminosity for Stars

• Stellar Classification (Harvard Computers)

• HR diagram

• Stellar Evolution

• Galaxy types & Classification

SOLAR SYSTEM


Sun

• Size compared to earth

• What type of star is the sun?

• Its ultimate fate & that of the solar system

• NOT a supernova!!!!!!!!!!!! NOT!


Terrestrial Planets in General

• Definition of Terrestrial Planets

• Basic Stats and Key Characteristics

• Rotation and Revolution

• Structure

• Surface

• Current & past habitability

• Formation and Evolution

• Differentiation, Cratering


Earth

• Terrestrial planets in general; the “habitable zone”

• The Atmosphere -- origin of oxygen

• Water & its role

• Life — unique

• Magnetic field -- dynamo effect

• Greenhouse effect and Climate Change and humans


Moon

• Characteristics and properties

• size

• cratering

• composition

• Highlands and maria

• Lunar exploration

• Formation — Giant Impact Hypothesis


Venus

• Temperature!

• Atmosphere -- runaway greenhouse

• Odd rotation

• No magnetic field to speak of

• No moons

• recent (but not current) vulcanism

• Why did Venus become not-habitable?


Mars

• Cold desert world

• once had abundant surface water

• Minimal magnetic field (no liquid iron)

• very thin atmosphere

• Surface

• N/S differences

• Olympus Mons & other Volcanos

• Valles Marinaris

• two moons

• Exploration -- rovers, Curiosity

• What happened to the water?

• Why is Mars red?


Jovian Planets

• Common Characteristics

• Size, no solid surface, stripes, rings, lots of moons

• Basic Stats and Key Characteristics

• Rotation and Revolution

• Structure

• Composition -- much like solar nebula

• Magnetic fields


Jupiter

• Largest planet, 11x diameter of Earth

• Galilean Moons

• Many more moons

• rings -- faint

• Geat Red Spot

• Very strong magnetic field

• Cloud-belt circulation


Jovian Moons

• Galilean

• Io - currently active volcanos

• Europa -- water under thick ice

• Ganymede -- largest satellite

• Callisto -- most cratered object in SS NASA Planetary Photojournal

“Family Portrait”


Saturn

• Similar to Jupiter

• Smaller

• weaker magnetic field

• Dramatic Rings

• Shepherd Moons

• Gaps

• Fairly large ice particles

• Up to person sized or so

• VERY thin

• Exploration -- Cassini

Cassini composite image of Saturn

NASA/JPL/Space Science Institute


Saturn’s Moons

• Titan -- sort of earthlike but with hydrocarbon sludge & nitrogen atmosphere. Cold. Shoreline featurs

• Enceladus -- water ice world, tidal flexing, ice vulcanism

• many more!

• shepherd moons within ring system


Uranus and Neptune

• Smaller & Colder than Jupiter and Saturn

• Blue/blue green color from methane

• “Wierd” poorly understood Magnetic Fields

• Uranus unusual rotation

• Neptune discovered due to irregularities in Uranus’ orbit


Dwarf Planets & Small Bodies

• Dwarf Planets

• The Pluto saga

• Meteroid, Meteor, Meteorite

• composition and significance

• Asteroids

• Comets

• The Kuiper Belt

• The Oort Cloud

STARS & GALAXIES


Stellar Properties

• Luminosity

• Distance ladder & difficulty of distances

• Stellar parallax

• know how angle & distance relate

• Standard Candle

• how does a standard candle work

• Magnitude system

• Apparent vs. Absolute magnitude

• review the ranking tasks


Spectral Type

• Color ~ temperature ~ spectral class

• be able to answer questions based on the blackbody LT

• Harvard computers & Harvard classification scheme

• OBAFGKM

• Brightness and temperature and size (Giants)


HR Diagram

• What is it?

• What can be plotted on it?

• Main sequence

• Red giants

• Supergiants

• White Dwarfs

• Evolution

• Sketch HR diagrams

• Pick out object types on HR diagrams


Stellar Lifecycles

• Star formation

• Main Sequence lifetime

• End states and what determines them

• Mass is everything!!!!!

• More mass means shorter life

• high mass is > ~ 4 times Sun

• remnant of < 2-3 times sun forms neutron star

• larger remnant forms black hole

© NASA


Main Sequence & Red Giant phase

• Main Sequence

• Hydrostatic Equilibrium

• H to He nuclear fusion — mass conversion

• Most of a star’s life

• Sun is on MS

• Red Giant

• loss of “engine”

• New hydrostatic equilibrium

• H to He fusion in shell

• He fusion in core

• 1/10th the duration of MS lifetime


Endgame Scenarios

• Low Mass

• Giant stars

• Planetary nebulae

• White dwarfs

• High Mass Stars

• Type II supernovae

• neutron stars & pulsars

• black holes

• type Ia supernovae


Galaxy Classification

NASA/ESA


Characteristics of types

• Describe spirals, barred spirals, ellipticals, irregulars

• identify from image

• Which are most common?

• What are their overall properties?

• Which tend to have older/red or younger/blue stars

• Which tend to have black holes (all)

Documents

ABOUT THE MIDTERM F2015 R… · Astronomy 1 - Elementary Astronomy LA Mission College Levine F2015 About the Midterm • KEY ideas: • Terrestrial planet characteristics vs. Jovian