Download "Stars" Power Point notes

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Cosmic distance ladder wikipedia, lookup

Aquarius (constellation) wikipedia, lookup

Ursa Minor wikipedia, lookup

Corvus (constellation) wikipedia, lookup

Boötes wikipedia, lookup

Perseus (constellation) wikipedia, lookup

Corona Australis wikipedia, lookup

Aries (constellation) wikipedia, lookup

Canis Major wikipedia, lookup

Auriga (constellation) wikipedia, lookup

Cygnus (constellation) wikipedia, lookup

Canis Minor wikipedia, lookup

Cassiopeia (constellation) wikipedia, lookup

Corona Borealis wikipedia, lookup

Timeline of astronomy wikipedia, lookup

Hipparcos wikipedia, lookup

Observational astronomy wikipedia, lookup

Lyra wikipedia, lookup

Serpens wikipedia, lookup

CoRoT wikipedia, lookup

Ursa Major wikipedia, lookup

Stellar evolution wikipedia, lookup

Star formation wikipedia, lookup

Type II supernova wikipedia, lookup

Stellar kinematics wikipedia, lookup

Dyson sphere wikipedia, lookup

Star catalogue wikipedia, lookup

Star wikipedia, lookup

Malmquist bias wikipedia, lookup

Star of Bethlehem wikipedia, lookup

SN 1054 wikipedia, lookup

Transcript
Notes - Stars
Chapter 12, Lesson 1
Stars
• Stars are balls of gas, mostly hydrogen, that
produce light by nuclear reactions in their
cores.
Star Structure
• Stars have layered structures.
• Energy is produced in the core.
• Temperatures range from 5,000,000 K to
100,000,000 K in the core.
• Atoms separate from their nuclei, forming
plasma.
Star Structure
Star Types
• Stars have many
diameters, masses, and
surface temperatures.
• Our Sun is a mediumsized star with a surface
temperature of about
5800 K.
Star Types
Properties of Different Types of Stars
Type
Supergiant
Diameter
(1=Sun’s dia.)
100 – 1,000
Mass
(1=Sun’s mass)
8-17
Surface
Temp. (K)
Variable
Red Giant
10-100
1-4
3,000 – 4,000
Main
Sequence
White Dwarf
0.1 – 15
0.1 – 60
2,400 – 50,000
0.01
0.5 – 1.44
6,000 – 100,000
Neutron Star
0.00
1-4
variable
Star Distances
• One AU is the average distance between the
Sun and Earth.
• A light-year is the distance light travels in
one year: 9,500,000,000,000 km or 63,000
AU.
Star Distances
Star Composition
• Stars can only be studied
by the light they emit.
• A spectroscope is an
instrument that is used to
study light.
• Astronomers can
determine what elements
are present in a star.
Star Composition
• Light split by a prism into a rainbow is a
continuous spectrum.
• A continuous spectrum is emitted by hot,
dense materials, such as the gas of the Sun’s
photosphere.
Star Composition
• Dark lines are sometimes seen in a
spectrum, called an absorption spectra.
• Absorption spectra are produced when light
passes through cooler gases that absorb
certain wavelengths.
Star Composition
• Each element absorbs only certain
wavelengths.
Star Composition
• Absorption lines help astronomers identify
elements in stars.
Star Temperature
• As metal gets hotter, it changes from red to
yellow to white.
• The color of stars also depends on
temperature.
Star Temperature
• Every object emits electromagnetic
radiation.
• The wavelength emitted depends on the
temperature of the object.
- Objects at room temperature emit long, infrared
waves.
- As temperature rises, wavelengths become
shorter.
Star Temperature
Star Temperature
Oh Boy, Another F's Gonna Kill Me.
The
temperature of
a star is
indicated by
the color it
glows.
(The Harvard
Stellar
Classification
System)
Type of Star
Color
Surface Temp (oC)
O
Blue
Above 25,000
B
Blue-White
10,000 – 25,000
A
White
7,500 – 10,000
F
Yellow-White
6,000 – 7,500
G
Yellow
5,000 – 6,000
K
Orange
3,500 – 5,000
M
Red
Below 3,500
Star Brightness
• The brightness of stars depends on
two things: energy and distance.
• Light looks brighter as you move
closer to the source.
• Luminosity is measured by how
much energy in joules is released
per second.
• One joule per second is called a
watt.
Star Brightness
• Apparent magnitude is the apparent
brightness of a star as measured on Earth.
- Apparent magnitude depends on the star’s
actual brightness and distance.
- The smaller the magnitude number, the brighter
the star. (http://spaceweather.com/flybys )
Star Brightness
• Absolute magnitude is the apparent
magnitude it would have if it were 32.6
light years away from Earth.
Star Brightness
Star Classifications
• Two astronomers independently developed
diagrams of how absolute magnitude, or
luminosity is related to the temperature of
stars.
• The diagram that plots temperature vs.
absolute magnitude is called the
Hertzsprung-Russell Diagram.
Star Classifications
• 90% of stars fall on a diagonal, curved line,
called the main sequence.
• The remaining stars fall into one of three
other groups.
- Red giants
- Supergiants
- White dwarfs
Star Classifications
Star Classifications
The apparent brightness of a star
depends on what two things?
A magnitude and distance
B distance and temperature
C distance and absolute brightness
D absolute brightness and temperature
12.1 Stars
A light-year is a unit of ____.
A time
B temperature
C brightness
D distance
As a star increases in absolute
magnitude, it appears ____ on Earth.
A larger
B hotter
C brighter
D more dense
The average distance between Earth
and the Sun is called a(n) ____.
A light-year
B astronomical unit
C angstrom
D solar unit
SCI 4.d
A star that is blue in color is ____
than a star red in color.
A hotter
B cooler
C larger
D smaller