Grace Adornetto Interpreting Stellar Data
pdf
keyboard_arrow_up
School
Bucks County Community College *
*We aren’t endorsed by this school
Course
102
Subject
Astronomy
Date
Dec 6, 2023
Type
Pages
3
Uploaded by GeneralLyrebird2546
Interpreting Stellar Data
Background:
This week we continue learning about the properties of stars. One of these key properties is
luminosity. Luminosity is the power a star emits. We measure luminosity using Absolute
Magnitude. The more negative the Absolute Magnitude, the more powerful the star. As we will
see with next week’s Learning Activity, Luminosity is one of the properties used to create the
H-R Diagram.
Despite how powerful the star, though, to us on Earth we may not necessarily know how
powerful a star really is because it only appears so bright to us. The star could be the most
powerful in the universe, but if it is really far away, we may only see a dim light. How bright a
star appears to us is called the star’s Apparent Brightness. Apparent Brightness is a second key
stellar property, and we measure it using Apparent Magnitude. Just like with Absolute
Magnitude, the more negative the value for Apparent Magnitude, the brighter the star is to us, or
the greater its Apparent Brightness.
A third stellar property is the star’s surface temperature. We measure that using the star’s
Spectral Type/Class (or color), and we categorize the different spectral types as OBAFGKM.
The star’s surface temperature is the second property used to construct the H-R diagram. O
stars are bluish in color and have very high surface temperatures, whereas M stars are redder
and cooler.
Instructions:
Use the table below, the information above, and your notes to answer the questions that follow
about the stars in this table.
Star
Absolute
Magnitude
Apparent
magnitude
Spectral
Type/Class
Aldebaran
-0.2
+0.9
K5
Alpha Centauri A
+4.4
0.0
G2
Antares
-4.5
+0.9
M1
Canopus
-3.1
-0.7
F0
Fomalhaut
+2.0
+1.2
A3
Regulus
-0.6
+1.4
B7
Sirius
+1.4
-1.4
A1
Spica
-1.6
+0.9
B1
Q1.
Which star appears brightest in our sky?
●
Sirius
Q2.
Which star appears faintest in our sky?
●
Regulus
Q3.
Which star has the greatest luminosity?
●
Antares
Q4.
Which star has the least luminosity?
●
Alpha Centauri A
Q5.
Which star has the highest temperature?
●
Spica
Q6.
Which star has the lowest temperature?
●
Antares
Q7.
Which star is most similar to our Sun?
●
Alpha Centauri A
Q8.
Place the stars in the table in order from greatest luminosity (1) to least luminosity (8).
(1) Antares
(5) Aldebaran
(2) Canopus
(6) Sirius
(3) Spica
(7) Fomalhaut
(4) Regulus
(8) Alpha Centauri A
Q9.
Place the stars in order from highest temperature (1) to lowest temperature (8).
(1) Spica
(5) Canopus
(2) Regulus
(6) Alpha Centauri A
(3) Sirius
(7) Aldebaran
(4) Fomalhaut
(8) Antares
Q10.
Which star would you expect to glow blue?
●
Spica and Regulus
Q11.
Which star would you expect to glow red?
●
Antares
Q12.
Explain the reasoning for your answer to Q10 and Q11.
●
The color of a star is determined by the energy wavelength emitted by the star, which is
determined by its surface temperature. Hot stars emit blue light, whereas colder stars
release red rays.
Q13.
If we all moved to Mars, what would happen to the apparent magnitude of the Sun?
Explain your answer.
●
The apparent magnitude of a star drops as the observer's distance from the star rises.
As we approach closer to Mars (the distance between us and the sun), the apparent
magnitude will decrease.
Q14.
If we were on Mars, what would happen to the absolute magnitude of the Sun?
Explain your answer.
●
The apparent magnitude of a star is defined as its absolute magnitude when seen from a
distance of 10 parsecs. Because distance is constant, it has no influence on absolute
magnitude.
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
- Access to all documents
- Unlimited textbook solutions
- 24/7 expert homework help