Download STARS Chapter 8 Section 1

STARS
Chapter 8 Section 1
What we will talk about today
• What color tells us about the temperature of
a star
• How we can identify what a star is made of
• How a star’s brightness, location, and
distance from earth are measured
What are stars?
• Stars are huge, bright balls of burning gas.
• Stars are different colors because of their
temperatures, and scientists can tell how
much heat a star gives off by studying its color.
• Who has used a
telescope?
Bunsen Burner vs. Candle
What flame is hotter? The flame of the
Bunsen burner or the candle?
Colors of Stars
• A blue flame is much hotter than a yellow one.
• Stars are similar: blue stars burn hotter than
yellow ones.
• Red stars are coolest.
• This is Betelguese,
a Red Giant Star
What color is our sun?
What temperatures are these stars?
What are stars made of?
• Stars are made of gas. Hydrogen(H) and helium(He)
are the two main elements that make up a star.
• What is an element?
• Stars also contain small amounts of other elements,
such as carbon, nitrogen, and oxygen. Each star is
made up of a different mix.
• To find out what a star is made of scientists study the
light from the stars.
What is light?
Light is actually made up of many colors. These
colors are called the spectrum.
• Many colors make up a spectrum, including
**red, orange, yellow, green, blue, indigo, and
violet. ROY G BIV will help you remember the
spectrum.
Where else have you
seen these colors?
Why do Scientists Study Light?
• Scientists are able look at light through a machine
called a spectrograph to break up a star’s light into a
spectrum.
• Each element has a particular pattern of lines that
appear in an emission spectrum. The emission
spectrum shows scientists what elements are in the
star.
• What can studying a star’s spectrum tell an astronomer?
Another way to describe stars:
Magnitude or Brightness
• Scientists give each star a number to show its
brightness, or magnitude.
• The dimmest stars have the largest
magnitude numbers.
• The brightest stars have the
magnitude
numbers.
smallest
What is the brightest star?
Quick Vocabulary Review
• What does apparent mean?
1)Clearly understood 2)Seeming real or true, but
not necessarily so.
• What does absolute mean?
complete
• What does actual mean?
Existing in fact
One type of magnitude
• The brightness(or magnitude) of a star as we see it
from Earth is the star’s apparent magnitude.*** A
bright star can look very dim if it is very far away from Earth. A
dim star can appear bright if it is closer to Earth.
• Where would you see the apparent magnitude of a star?
Absolute Magnitude
• A star’s absolute magnitude is the actual
brightness of the star.
• Astronomers use a star’s apparent magnitude
and its distance from earth to calculate its
absolute magnitude.****
• What can we tell about
these stars magnitudes?
What do scientists use to calculate
distance to stars?
• Because stars are so far away, astronomers
use light years to measure the distance from
Earth to the stars.
• A light year is the distance that light travels in
one year, or 186,282 miles per second, or 5.88
trillion miles****
This quasar is 10 billion light
years from Earth
Motion of the Stars
As we stand on Earth and look at the stars, they seem to move.
This is because the Earth revolves around the sun and we are
on the surface of the Earth as it revolves. This is called stars’
Apparent Motion.
What has moved?
Based on what you
Now know about
Apparent Motion,
What would Actual
Motion be????
Measuring the distances of stars
with parallax****
• Parallax is the object’s apparent shift in motion when
viewed from different locations. It is an optical effect.
• Astronomers can measure parallax and use it to
calculate exact distances to stars.
• Does the man on the right(V2) see the moon as
closer or farther away than the man on the left?
• Where would
someone use
parallax?
To sum it all up…….
Why do some stars look different than others?
When we look at a star from Earth, will it look
the same in 6 months? Why?