How Are the Properties of Stars Related?

Name ______

Period ______

How are the properties of stars related?

Essential Questions: How can we make meaning out of numbers?

Task: You are a member of a team of scientists that is studying one of outer arms of a newly discovered spiral galaxy. Your research team has just completed data collection on the color, temperature, and luminosity of the thirty outermost stars. Your objectives are to 1)plot the stardata on a graph, 2)use the graph to analyze the data and 3) describeobserved relationships between the properties of the stars.

Directions:

Plot and label the stars on the graph using the correct colors to indicate the color of the stars
Label the Axes of the graph (include units)
Title the graph (see rubric for specific requirements)
Clearly communicate your answers to the analysis questions using complete sentences and scientific vocabulary
Complete the self-assessment rubric to check your work before you turn it in

Name / Temperature
(K) / Luminosity
(solar units) / Color / Name / Temperature
(K) / Luminosity
(solar units) / Color
Alpha / 5,800 / 1.56 / yellow / Papa / 34,000 / 200,000 / Blue
Bravo / 2,800 / .0005 / red / Quebec / 7,400 / 1,510 / White
Charlie / 2,700 / .00002 / red / Romeo / 3,400 / 5,500 / red
Delta / 3,200 / 0.006 / red / Sierra / 4,500 / 115 / orange
Echo / 10,400 / 23.5 / Blue-white / Tango / 10,700 / 55 / Blue-white
Foxtrot / 2,700 / 0.00006 / red / Uniform / 5,900 / 5 / Yellow
Golf / 2,800 / 0.0005 / red / Victor / 11,800 / 46,000 / Blue-white
Hotel / 8,000 / 0.001 / white / Water / 30,000 / 100,000 / Blue
India / 4,500 / 0.3 / orange / X-ray / 3,200 / 14,000 / Red
Juliet / 2,800 / 0.0004 / red / Yankee / 14,000 / 219 / Blue-white
Kilo / 2,700 / 0.0001 / red / Zulu / 9,500 / 13.8 / Blue-white
Lima / 3,600 / 0.08 / orange / Alpha Alpha / 8,000 / 11.5 / white
Mike / 6,800 / 7.65 / Yellow-white / Bravo Bravo / 4,900 / 105 / Orange
November / 4,200 / 0.14 / orange / Charlie Charlie / 4,200 / 105 / Orange
Oscar / 3,000 / 0.003 / red / Delta Delta / 21,000 / 2,400 / Blue-white

Data Analysis- Please respond with complete sentences and scientific vocabulary.

Identify the color classification that represents the mode of the data. Use the data as evidence to justify your answer. (2 points)

Identify the relationship between a star’s temperature and luminosity as causal or correlation. Explain your rationale. (2 points)

Identify the relationship between a star’s temperature and luminosity as directly or inversely proportional. Explain your rationale. (2 points)

Use data points from your graph to complete the table below. Sequence the colors and temperatures from hottest at the top to coolest at the bottom (1 point per cell)

Spectral Class / Color / Temperature
O
B
A
F
G
K
M

5. Which color classification had the largest temperature range? What is the range for that data subset? (2 points)

6. Which color classification had the largest luminosity range? What is the range for that data subset? (2 points)

7. Make a logical prediction to explain why there are outliers from the data trend on the graph. (2 points)

Advanced/Gifted (answer these instead of 2 and 3 above)

2. One of your teammates on the research team states that luminosity determines a star’s color, but you argue that color is determined by the star’s temperature. Use specific data from your graph as evidence to support this argument. (2 points)

3. Another of your colleagues states that the relationship between temperature and luminosity must be inversely proportional because the slope of the data is negative. Do you agree or disagree? Explain. (2 points)

100000

10000

1000

100

0.1

0.01

0.001

0.0001

40000 35 000 30 000 25 000 2000015 000 10000 5 000 0

CATEGORY / 5 / 3 / 1 / 0 / Self- Assessment / Teacher Assessment
Title / Title clearly relates to the problem being graphed (includes both properties). It is printed at the top of the graph. / Title relates to the problem being graphed (lacks clarity in one or both properties) and is printed at the top of the graph. / A title is present at the top of the graph but does not relate to the problem being graphed. / A title is not present.
Accuracy of Plot / All points are plotted correctly and are easy to see. A ruler is used to neatly make a trend line. / Most points are plotted correctly and are easy to see. / Some points are plotted correctly, but there are many inaccuracies. / Most points are plotted incorrectly OR extra points were included.
Labeling of X axis / The X axis has a clear, neat label that correctly identifies the units used to measure temperature. / The X axis has a clear label that correctly identifies the unit used to measure temperature. / The X axis has a label but the correct unit is not included. / The X axis is not labeled.
Labeling of Y axis / The Y axis has a clear, neat label that identifies the units used to measure luminosity. / The Y axis has a clear label that correctly identifies the units used to measure luminosity. / The Y axis has a label but the correct unit is not included. / The Y axis is not labeled.

Scatterplot Rubric – Please use the self-assessment to check your graph before turning it in.

Graph Score ______

Total Score

Graph Score / / 20
Analysis Score / / 26
Total Score / / 46

The following pages are intended for teacher use only.

Data Analysis - KEY

Identify the color classification that represents the mode of the data. Use the data as evidence to justify your answer. (2 points)

The mode is represented by red stars because there more red stars than any of the other colors. There are 11 red stars, 7 blue-white stars, 6 orange stars, 2 yellow stars, 2 white stars, two blue stars, and 1 white star.

Identify the relationship between a star’s temperature and luminosity as a causal or correlation. Explain your rationale. (2 points)

The relationship between a star’s temperature and luminosity is a correlation because one does not affect the other. Each of these properties is dependent upon the star’s mass.

Identify the relationship between a star’s temperature and luminosity as directly or inversely proportional. Explain your rationale. (2 points)

The relationship between a star’s temperature and luminosity is directly proportional because one increases as the other is increasing and/or one decreases as the other is decreasing.

Use data points from your graph to complete the table below. Sequence the colors and temperatures from hottest at the top to coolest at the bottom (1 point per cell)

5. Which color classification had the largest temperature range? What is the range for that data subset? (2 points)

Based on the data, blue-white stars have the largest range ofapproximately 12,500K.

Spectral Class / Color / Temperature
O / Blue / 30,000 – 34,000
B / Blue-White / 9,500 -21,000
A / White / 7,400-8,000
F / Yellow White / 6,000 – 7,400
G / Yellow / 4,900 – 6000
K / Orange / 3,500 - 4,900
M / Red / 2,000 - 3,500

6. Which color classification had the largest luminosity range? What is the range for that data subset? (2 points)

The red stars had the largest range of approximately 10,000 solar units.

7. Make a logical prediction to explain why there are outliers from the data trend on the graph. (2 points)

The stars that lie above the main set of data are larger than the others of the same color (Giants and Supergiants) and the one that falls below the main sequence is much smaller (Dwarf). Accept any other reasonable explanation.

Advanced/Gifted (answer these instead of 2 and 3 above)

Outliers show that luminosity may vary when temperature is constant, but temperature ranges will correlate with color regardless of the luminosity. For example, star Victor has a temperature is 48,000 which falls within the blue range; however, its luminosity is much higher than the other blue and blue-white stars.

I disagree with my colleague. Even though the slope of the graph appears to be negative at first, the numeric values along the x axis are reversed compared to the typical format of a graph, which goes from lower values on the left to higher values on the right. Evaluating the data points on the graph, the general trend shows that luminosity increases proportionally to temperature because one increases as the other increases and/or one decreases as the other decreases.

Star data used to create table

Name / Temperature
(K) / Luminosity
(solar units) / Name / Temperature
(K) / Luminosity
(solar units)
A / Alpha Centauri / 5,800 / 1.56 / P / UW Canis Majoris / 34,000 / 200,000
B / Barnard's Star / 2,800 / .0005 / Q / Canopus / 7,400 / 1,510
C / Wolf 359 / 2,700 / .00002 / R / Antares / 3,400 / 5,500
D / Lalande 21185 / 3,200 / 0.006 / S / Arcturus / 4,500 / 115
E / Sirius / 10,400 / 23.5 / T / Vega / 10,700 / 55
F / Proxima Centauri / 2,700 / 0.00006 / U / Capella / 5,900 / 166
G / Ross 154 / 2,800 / 0.0005 / V / Rigel / 11,800 / 46,000
H / Procyon B / 8,000 / .001 / W / Beta Centauri / 30,000 / 100,000
I / Epsilon Eridani / 4,500 / 0.3 / X / Betelgeuse / 3,200 / 14,000
J / Ross 128 / 2,800 / 0.0004 / Y / Achernar / 14,000 / 219
K / Luyten 789-6 / 2,700 / 0.0001 / Z / Fomalhaut / 9,500 / 13.8
L / 61 Cygni / 3,600 / 0.08 / AA / Altair / 8,000 / 11.5
M / Procyon / 6,800 / 7.65 / BB / Pollux / 4,900 / 41.7
N / Epsilon Indi / 4,200 / 0.14 / CC / Aldebaran / 4,200 / 105
O / Sigma 2398 / 3,000 / 0.003 / DD / Spica / 21,000 / 2,400

Star data obtained from: