Download Sunspots - Sage Middle School

The Sun, our favorite star!
The Sun is the basis
for all of our
knowledge of stars.
Why?
WE CAN SEE IT REALLY WELL.
Kelvin Temperature Scale
temperature
kelvin
degree Celsius
degree Fahrenheit
symbol
K
°C
°F
boiling point of
water
373.15
100.
212.
melting point of
ice
273.15
0.
32.
absolute zero
0.
-273.15
-459.67
Humans
310
37
98.6
Sun
5800
5527
9980
Today we will take a journey
from the center of the Sun,
starting just outside the core…
…and ending up deep in
the corona.
Overview of Solar Structure
(aka, our Sun as a jawbreaker)
Main Parts:
 Corona
 Chromosphere
 Photosphere
 Convection Zone
 Radiative Zone
 Core
The Sun is made of mostly
HYDROGEN and HELIUM
Rotation
25 Days at the Equator
35 Days at the Poles
This twisting leads to the loopy
structures we see!
The Core
Fusion takes place here.
p
p
p
n
p
p
4H
Fusion Animation
n
p
+ Energy
1He
http://astro.unl.edu/classaction/animations/
sunsolarenergy/fusion01.html
The interior of the Sun…
• Energy is generated in the core, but how does
it get out and end up as sunshine?
The next two layers of the Sun are all about
getting the energy being made in the core out
into space!
How does energy get from one place
to another?
1.
Convection
2.
Conduction
3.
Radiative Diffusion
Convection and Radiative Diffusion are
most important for the Sun!
Radiative Diffusion
The photons
“diffuse” outwards,
heating the gas as
they go.
Ionized
gas
• Photons can “scatter” off of unbound
electrons
• When they scatter, the photons
share their energy with the electrons
• The electrons get hotter
The Radiative Zone
Here, photons
bounce around in a
“random walk”
Ionized
gas
Eventually they
make it out of the
radiative zone, but
it takes a long, long
time!
Convection
Hot stuff
rises…
Cool stuff
sinks!
Hot water goes up to the surface while cool water
sinks down -- cool water then gets heated and rises
a.k.a:
BOILING
The Convective Zone
Photosphere
The Convective
Zone is the layer
just under the
photosphere
Convective “cells”:
As seen from the top, these are the granules we
see in the photosphere
Conduction
Metal of the pan
heats by
conduction…
…heat travels
through the atoms
of the pan
Not very important for
stars!
PHOTOSPHERE
Characteristics
•the part of the sun we see
•one of the coolest parts at 6000K
•densest part of solar atmosphere
•contains sun spots, granules (ation)
Photosphere temperature is about
5800 K…
• Remember how the temperature and color of stars
are related? The temperature of our Sun gives it its
yellowish color!
Our Sun is really yellowish
green, but our
atmosphere absorbs and
scatters some of the blue
light.
The photosphere has some
interesting features too…
Sunspots:
Regions where magnetic field pokes
through the photosphere.
Sunspots are cooler than surrounding
stuff, so they look dark!
Granules:
Where the roiling, boiling convection zone
underneath bubbles up.
Sunspots
•dark cooler (4000K vs. 5800K) regions on the sun
•last several days to several weeks
•caused by the sun’s magnetic field upwelling to the
photosphere
•occur in cycles
•contribute to solar storms such as flares and coronal
mass ejections
Sunspot pairs
Describe what you see
in this image to someone
in class
Explain what you see in this picture to
someone else in class.
Granulation
•Cover the sun’s surface
•approx. 1000km across
(Texas sized)
•tops of convection cells
•white centers are hotter
than dark edges
•flow can be up to
15000 mph
•individual cells last
20 min
http://www.youtube.com/watch?v=zxzhfijFML
8&feature=related
CHROMOSPHERE
Characteristics
•red color due to hydrogen emission lines
•temperature 4500K to 10000K
•prominences form here
•2500 km thick
•spicules (jets of plasma) form here
Spicules
•small jet like eruptions that last a few minutes
•send material out into corona at 20-30 km/s
TRANSITION REGION
•Region of rapid temperature change between
chromosphere and corona
THE CORONA
•temperature 1-3 million K
•very irregularly shaped
•strong x-ray emitter
•uncertain as to why it is so hot
•coronal holes are the origin of the
solar wind
•produces an absorption and
continuous spectrum
http://www.nasa.gov/mission_pages/sunearth/news/colorful-science_prt.htm
Coronal Mass Ejections
•Huge bubbles of gas ejected
from the sun
•Can cause problems with
communications
•Often occur with flares
SOLAR WIND
Current Solar Wind
Data can be found at
www.spaceweather.com
•low density gases (ionized hydrogen)
•travels 300 to 1000km/s
•sun loses 10,000,000 tons of mass per
year
A short Video
Earth to scale.
Yes, really.