learning more about stars: hertzsprung-russell diagram
Post on 31-Dec-2015
39 Views
Preview:
DESCRIPTION
TRANSCRIPT
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tLearning More About Stars:
Hertzsprung-Russell Diagram• We already know lots about stars:
– Their temperatures can be determined from their color – blue means hot and red means cool
– Their distances can be determined by parallax and many other means
• Can we learn still more?
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
t Making charts can be power
• We can use charts to draw conclusions about things unseen.
• Let’s consider charting weights and heights for a group of students.
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
t Making the chart…
• Draw a set of X-Y axes
• On the X-axis, place weight with 0 lbs to the left and 200 lbs to the right
• On the Y-axis, place height with 0 ft at the bottom and 7 ft at the top
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
t Plot the following data points
Individual # Weight (lbs) Height (ft)
1 75 3
2 100 4
3 112 4.5
4 180 6
5 120 6.5
6 125 5
7 138 5.5
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tYour chart should look like
this• Draw a set of X-Y axes
• On the X-axis, place weight with 0 lbs to the left and 300 lbs to the right
• On the Y-axis, place height with 0 ft at the bottom and 7 ft at the top
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
t What can you infer about “5”?
• Draw a set of X-Y axes
• On the X-axis, place weight with 0 lbs to the left and 300 lbs to the right
• On the Y-axis, place height with 0 ft at the bottom and 7 ft at the top
5
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
t Making inferences
• You can tell that person 5 is in some way different from the rest of the people
• You can tell from the data that person 5 is very tall for the indicated weight.
• You can infer that someone who is very tall and weighs very little is…
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
t Conclusions
• You should have concluded the person 5 is very slender, even thin compared to the “main sequence” of other persons.
• What would you conclude if someone on the chart’s position was below the “main sequence” of other people?
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
t And so it is with stars
• Astronomers have learned that if they make similar charts for stars (luminosity versus temperature), they can draw certain conclusions about stars too much like we have just done with humans! We don’t need to see stars “close up” in order to infer.
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tLuminosity vs Temperature 10.0
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by temperature10.1
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by temperature10.2
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by temperature10.3
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by temperature10.4
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by temperature10.5
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by temperature10.6
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by temperature10.7
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tNow, separate by luminosity 10.7
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by luminosity 10.8
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by luminosity 10.9
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by luminosity 10.10
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by luminosity 10.11
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
t10.12Separate stars by luminosity
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tSeparate stars by luminosity 10.13
Hot Temperature Cool
Dim
Lu
min
osity
B
rill
ian
tH-R Diagram: Inferring Size
1) Main Sequence 2) SubGiant
Branch
3) Red Giant Branch
4) Horizontal Branch
5) White Dwarf Sequence
10.14
top related