Stellarium Project—Part 2
Name:_______________________
Due: Wed Dec. 2
A. For this part, we will focus on the most obvious constellation in the winter sky: Orion
(a Hunter in Greek Mythology), which stands out because many of the stars in the
constellation are brighter than most. We will investigate what kinds of stars they are and
what distances they are from us.
For an amazing and incredibly deep, long exposure of Orion taken in visible light, see the
Astronomy Picture of the Day for Nov. 23. If you put your cursor overt the image, it has
labels for the different objects. http://apod.nasa.gov/apod/ap151123.html
Use Stellarium to fill out the following table for the 3 brightest stars in Orion. Rigel is a
“knee”, Betelgeuse is a “shoulder” and Alnilam is the middle star in the “belt” of 3 stars.
You can use the “search” (magnifying glass icon) feature to make sure you are getting the
correct object if you have trouble clicking on it. For the “Type of star” describe the
luminosity class of the star in words. I= supergiant, II=bright giant, III=giant,
IV=subgiant, V=main sequence. Note that Stellarium does not have complete information
(spectral types and luminosity classes, distances, etc.) for all of the stars in the database,
but the bright stars have them.
Set the date and time to November 30 at 10:00pm (22:00:00). Orion will be rising in the
east. You will also see the brightest star in the sky, Sirius, just southeast of Orion.
Star Name
Apparent
Mag.
Absolute
Mag.
Spectral Type
Type of star
Distance (in
light-years)
1) Rigel
2) Betelgeuse
3) Alnilam
For the above 3 stars
Which is the closest star?____________
Which is the farthest star?____________
Which is the most luminous star?___________
Which is the coolest star?_____________
Which is the hottest star?________________
Click on other bright stars in Orion that are not in the table. Are ANY of them on the main
sequence? Y N If so, list one:
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B. The stars below are the 3 brightest (apparent magnitude) stars in the sky besides the
Sun. Data are from Appendix 3 in the textbook rather than from Stellarium.
Place the 3 stars from Orion and the 3 stars in the table below on the HR diagram on the
next page. Make sure you have all 6 on the HR diagram. For clarity, put a dot for each
star on the diagram and then draw a line off to the side with each star’s name labelled.
You may want to draw light grid lines to help you plot the points. The spectral type
subclasses go from 0 to 9 from left to right of the label (the label itself, such as “F” is at
the middle, or F5).
Star Name
Apparent
Mag.
Absolute
Mag.
Spectral Type
Type of star
Distance (in
light-years)
4) Sirius
5) Canopus
6) Arcturus
-1.47
-0.72
-0.04
1.42
-5.53
-0.29
A1V
F0II
F1.5III
Main sequence 8.60
Bright giant
313
Giant
36.7
Extra Credit: Using absolute and apparent magnitude found in Stellarium, estimate the
distance to Rigel. Compute X = (m-M+5)/5. m=apparent and M=absolute magnitude.
Then take d = 10X in your calculator to get the distance in pc. Then multiply by 3.26 to
convert pc to light years.
Calculation of distance to Rigel in light years (show work). Round off your answer to 3
significant figures.
Does it agree well with the value you entered in the table? (it should!)
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C. We will now explore some objects that are not single stars. Some of these are too faint to be seen
without binoculars or a telescope. Note the “M” is after Charles Messier, who made a catalog of “objects
that are not comets” in the 1780’s. You will need to zoom in (control or command- up arrow) in order to
see them well enough to sketch them. Use pencil and/or colored pencils or ink for your drawings.
1) Find the Orion Nebula (also called M42 and the Great Nebula in Orion). It is a stellar nursery where
stars are still being born out of a cloud of dust and gas. Some young, hot stars are illuminating the nebula.
What is its magnitude?_________________ Sketch it below.
2) The Crab Nebula (M1): What kind of nebula is this (hint: what formed it? See textbook)
_______________________________
What is its apparent magnitude?_______________ Sketch it below:
3) Globular Cluster M15. There are about 100,000 stars in this cluster and it is one of the oldest clusters
in the galaxy, with an age of about 12 billion years and a distance of 10 kpc. List the total apparent
magnitude of the cluster__________ Sketch it below.
4) The Andromeda Galaxy (M31). Find it and zoom in. You will see one large galaxy (M31),
and two small galaxies (M32 and M110).
What kind of galaxy is M31? __________________What is its total magnitude?_____________
M32 and M110 are satellite galaxies of M31 What kinds of galaxies are they? ______________
Sketch and label M31, M32, and M110 below:
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D. The next total solar eclipse that will be visible in the United States will be on Aug. 21, 2017. You
should plan on seeing this spectacular event—all you need is to be in the path of totality and have clear
skies! It will only be a partial eclipse in Los Angeles. It will be total in a narrow strip of land stretching
from Oregon to South Carolina. To see exactly where the eclipse will be total (where the Moon’s umbra
hits the Earth) go to:
http://www.eclipsewise.com/solar/SEgmap/2001-2100/SE2017Aug21Tgmap.html
for an interative Google map showing details on the path of totality.
One city that is near the centerline of totality is Casper, Wyoming. Set your location to Casper (search for
it in the location search window) and set the date to Aug. 21, 2017 at 9:00 am. Select the Sun and center
on it and zoom up. Let time pass and watch the Moon pass in front of the Sun. During the partial phase,
the Moon covers up part of the Sun. During totality, the Moon completely covers up the Sun, the sky gets
dark enough to see bright stars and planets, and you will see the Sun’s corona (this is shown in Stellarium
and is less than 3 minutes long). Experiment with having time go slower and faster and zooming in.
You may have to center on the Sun again to keep it “frozen” on your screen as time passes (use fast
forward/fast backward as necessary).
Record the following times (list as hour: minute:second). Answer is OK if it’s within +/20 seconds of correct answer.
Beginning of partial eclipse (when the Moon first “contacts” the ege of thSun):
________________
Beginning of total eclipse:________________
End of total eclipse: _________________
End of partial eclipse:__________________
Change the location back to LA on that same day. Find the Sun that morning. What time
will the partial eclipse start in LA?_________________
Do you plan on seeing the eclipse?
If so, remember to use special eye protection (eclipse glasses) during the partial phase.
Don’t miss it!
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