Sketchbook: stellar evolution

See if you can identify everything in this doodle.

Astronomy quiz archive: stellar evolution

Astronomy 210 Quiz 6, fall semester 2019
Cuesta College, San Luis Obispo, CA

Section 70158
Exam code: quiz06sOr6


Section 70158

0- 8.0 :
8.5-16.0 :	**** [low = 13.5]
16.5-24.0 :	******
24.5-32.0 :	************ [mean = 27.5 +/- 6.9]
32.5-40.0 :	************ [high = 36.5]

Section 70160
Exam code: quiz06NyQ7


Section 70160

0- 8.0 :
8.5-16.0 :	****** [low = 11]
16.5-24.0 :	****** [mean = 21.7 +/- 6.8]
24.5-32.0 :	*******
32.5-40.0 :	** [high = 33]

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, fall semester 2019
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz05Sh0w


Section 70158

0- 8.0   :
8.5-16.0 :	*** [low = 10.0]
16.5-24.0 :	*
24.5-32.0 :	********* [mean = 32.0 +/- 8.2]
32.5-40.0 :	******************* [high = 40.0]

Section 70160, version 1
Exam code: quiz05NpRm


Section 70160

0- 8.0   :
8.5-16.0 :	* [low = 16.0]
16.5-24.0 :	**********
24.5-32.0 :	***** [mean = 26.0 +/- 7.5]
32.5-40.0 :	****** [high = 40.0]

Astronomy quiz archive: stellar evolution

Astronomy 210 Quiz 6, spring semester 2019
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz06nD4d


Section 30674

0- 8.0 :
8.5-16.0 :	**** [low = 9.0]
16.5-24.0 :	************
24.5-32.0 :	******* [mean = 24.7 +/- 7.9]
32.5-40.0 :	******** [high = 40.0]

Section 30676, version 1
Exam code: quiz06s33N


Section 30676

0- 8.0 :	* [low = 7.5]
8.5-16.0 :	*****
16.5-24.0 :	************** [mean = 23.5 +/- 6.5]
24.5-32.0 :	*****************
32.5-40.0 :	**** [high = 36.5]

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, spring semester 2019
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz05NiR0


Section 30674

0- 8.0   :
8.5-16.0 :	**** [low = 11.0]
16.5-24.0 :	***********
24.5-32.0 :	****** [mean = 26.2 +/- 8.7]
32.5-40.0 :	********** [high = 40.0]

Section 30676, version 1
Exam code: quiz05S4re


Section 30676

0- 8.0   :	** [low = 2.5]
8.5-16.0 :	**
16.5-24.0 :	********
24.5-32.0 :	*********** [mean = 27.6 +/- 9.2]
32.5-40.0 :	*************** [high = 40.0]

Astronomy quiz archive: stellar evolution

Astronomy 210 Quiz 6, fall semester 2018
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz06SeR3


Section 70158

0- 8.0 :	* [low = 8.0]
8.5-16.0 :	*******
16.5-24.0 :	************ [mean = 22.1 +/- 7.8]
24.5-32.0 :	**********
32.5-40.0 :	**** [high = 40.0]

Section 70160, version 1
Exam code: quiz06SNn5


Section 70160

0- 8.0 :	* [low = 8.0]
8.5-16.0 :	*****
16.5-24.0 :	****** [mean = 20.7 +/- 6.9]
24.5-32.0 :	*****
32.5-40.0 :	* [high = 33.0]

Astronomy quiz question: smallest star?

Astronomy 210 Quiz 5, fall semester 2018
Cuesta College, San Luis Obispo, CA

Which star is the smallest?
(A) A0 white dwarf.
(B) B5 main sequence star.
(C) K5 giant.
(D) M0 main sequence star (red dwarf).
(E) (There is a tie.)

Correct answer (highlight to unhide): (A)

An H-R diagram is provided with this quiz.


These stars are plotted on an H-R diagram below. The K5 giant is largest, followed by the B5 main sequence star, M0 red dwarf, and the A0 white dwarf is smallest.


Section 70160
Exam code: quiz05Oor7
(A) : 9 students
(B) : 1 student
(C) : 1 student
(D) : 5 students
(E) : 1 student

Success level: 55% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.20

Astronomy quiz question: hottest star?

Astronomy 210 Quiz 5, fall semester 2018
Cuesta College, San Luis Obispo, CA

Which star is the hottest?
(A) A0 white dwarf.
(B) B5 main sequence star.
(C) K5 giant.
(D) M0 main sequence star (red dwarf).
(E) (There is a tie.)

Correct answer (highlight to unhide): (B)

An H-R diagram is provided with this quiz.


These stars are plotted on an H-R diagram below. The B5 main sequence star is the hottest, followed by the A0 white dwarf, the K5 giant, and the M0 main sequence star (red dwarf) is the coolest. Instead of using the H-R diagram, the OBAFGKM mnemonic can be used to determine the temperatures of these stars from their spectral type.


Section 70158
Exam code: quiz05T3rA
(A) : 2 students
(B) : 0 students
(C) : 0 students
(D) : 20 students
(E) : 0 students

Success level: 78% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.67

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, fall semester 2018
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz05T3rA


Section 70158

0- 8.0   :	* [low = 8.0]
8.5-16.0 :	**
16.5-24.0 :	*********
24.5-32.0 :	********** [mean = 26.3 +/- 7.6]
32.5-40.0 :	*********** [high = 40.0]

Section 70160, version 1
Exam code: quiz05Oor7


Section 70160

0- 8.0   :	* [low = 8.0]
8.5-16.0 :	****
16.5-24.0 :	******** [mean = 20.1 +/- 6.7]
24.5-32.0 :	***
32.5-40.0 :	* [high = 36.0]

Astronomy final exam question: type II supernovae in star cluster with white dwarfs?

Astronomy 210 Final Exam, spring semester 2017
Cuesta College, San Luis Obispo, CA

An astronomy question on an online discussion board[*] was asked and answered:

Pdg: Can there be type II supernovae explosions seen in a star cluster that also has white dwarfs at the same time? Would it have to be a really old or young star cluster?
spota: Yes, if the star cluster is old enough to contain white dwarf stars it will still be young enough to have hydrogen-burning massive stars that can undergo type II supernova explosions.

Discuss why this answer is incorrect, and how you know this. Explain using the properties of mass and stellar lifetimes, evolution of stars, and star cluster ages.

[*] answers.yahoo.com/question/index?qid=20171117015031AAqCPQo.

Solution and grading rubric:

• p:
  Correct. Understands that star cluster cannot have type II supernovae explosions at the same time as having white dwarfs:
  1. medium-mass stars become white dwarfs well after the end of their main-sequence lifetimes (approximately 10 billion years); and
  2. massive stars will explode as type II supernovae after the end of their main-sequence lifetimes (less than a million years); such that
  3. a star cluster with white dwarfs, will not have any supergiants remaining that can explode as type II supernovae; or a star cluster with supergiants exploding as type II supernovae will have medium-mass stars that have not yet reached the end of their main-sequence lifetimes.
• r:
  Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors.
• t:
  Contains right ideas, but discussion is unclear/incomplete or contains major errors.
• v:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Garbled discussion of properties and evolution of stars. May discuss type Ia supernovae or lookback time.
• x:
  Implementation/application of ideas, but credit given for effort rather than merit. Discussion other than that of the properties and evolution of stars.
• y:
  Irrelevant discussion/effectively blank.
• z:
  Blank.

Grading distribution:
Section 30674
Exam code: finaln3sT
p: 6 students
r: 3 students
t: 5 students
v: 4 students
x: 1 student
y: 0 students
z: 1 student

Section 30676
Exam code: finalSuB1
p: 13 students
r: 6 students
t: 6 students
v: 6 students
x: 3 student
y: 1 student
z: 1 student

A sample "p" response (from student 1777):
A sample "p" response (from student 1217), discussing the house party model of determining star cluster ages:
A sample "y" response (from student 7237):

Astronomy quiz question: star cluster with medium-mass protostars

Astronomy 210 Quiz 6, spring semester 2018
Cuesta College, San Luis Obispo, CA

A star cluster with medium-mass protostars would also have __________ at the same time.
(A) massive main sequence stars.
(B) red dwarfs.
(C) white dwarfs.
(D) giants.

Correct answer (highlight to unhide): (A)

All stars in a star cluster are born at the same time, but undergo stellar evolution at different rates depending on their masses. Medium-mass stars start out as protostars, then reach their main sequence stage, and subsequently become giants, planetary nebulae, and then white dwarfs. So a star cluster with medium-mass protostars cannot have giants nor white dwarfs at the same time, as these are stages that follow the protostar stage of a medium-mass star.

A red dwarf is a low-mass star that has evolved from its protostar stage to its main sequence stage; this takes much longer for a medium-mass star to evolve from its protostar stage to its main sequence lifetime. So a star cluster with medium-mass main sequence stars cannot have red dwarfs at the same time.

A massive star will evolve from its protostar stage to its main sequence stage at a rate much rapidly than medium-mass stars. Thus it is plausible that a star cluster with medium-mass protostars can have massive main sequence stars at the same time.

Section 30676
Exam code: quiz06s0ho
(A) : 17 students
(B) : 5 students
(C) : 10 students
(D) : 10 students

Success level: 44% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.55

Astronomy quiz question: star cluster with medium-mass main sequence stars

Astronomy 210 Quiz 6, spring semester 2018
Cuesta College, San Luis Obispo, CA

A star cluster with medium-mass main sequence stars would also have __________ at the same time.
(A) red dwarfs.
(B) supergiants.
(C) white dwarfs.
(D) giants.

Correct answer (highlight to unhide): (B)

All stars in a star cluster are born at the same time, but undergo stellar evolution at different rates depending on their masses. Medium-mass stars start out as protostars, then reach their main sequence stage, and subsequently become giants, planetary nebulae, and then white dwarfs. So a star cluster with medium-mass main sequence stars cannot have giants nor white dwarfs at the same time, as these are stages that follow the main sequence lifetime of a medium-mass star.

A red dwarf is a low-mass star that has evolved from its protostar stage to its main sequence stage; this takes much longer for a medium-mass star to evolve from its protostar stage to its main sequence lifetime. So a star cluster with medium-mass main sequence stars cannot have red dwarfs at the same time.

A supergiant is a massive star that has evolved from its protostar stage to its main sequence stage, and subsequently used up all of its core hydrogen exit its main sequence stage. Since massive stars evolve much more rapidly than medium-mass stars, then it is plausible that a star cluster with medium-mass main sequence stars can have supergiants at the same time.

Section 30674
Exam code: quiz06nG4s
(A) : 8 students
(B) : 5 students
(C) : 4 students
(D) : 6 students

Success level: 28% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.43

Astronomy quiz archive: stellar evolution

Astronomy 210 Quiz 6, spring semester 2018
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz06nG4s


Section 30674

0- 8.0 :
8.5-16.0 :	**** [low = 11.0]
16.5-24.0 :	***
24.5-32.0 :	******** [mean = 27.3 +/- 8.9]
32.5-40.0 :	******** [high = 40.0]

Section 30676, version 1
Exam code: quiz06s0ho


Section 30676

0- 8.0 :	**** [low = 7.5]
8.5-16.0 :	******
16.5-24.0 :	*********** [mean = 23.8 +/- 9.4]
24.5-32.0 :	***********
32.5-40.0 :	********** [high = 40.0]

Astronomy quiz question: G5 white dwarf vs. M0 red dwarf

Astronomy 210 Quiz 5, spring semester 2018
Cuesta College, San Luis Obispo, CA

A G5 white dwarf and an M0 red dwarf could have the same:
(A) luminosity.
(B) size.
(C) temperature.
(D) (Two of the above choices.)
(E) (All of the above choices.)
(F) (None of the above choices.)

Correct answer (highlight to unhide): (F)

An H-R diagram is provided with this quiz.


These stars are plotted on an H-R diagram below. The G5 white dwarf is less luminous, smaller in size, and hotter in temperature than the M0 red dwarf.


Section 30674
Exam code: quiz05Sbn3
(A) : 0 students
(B) : 5 students
(C) : 0 students
(D) : 4 students
(E) : 0 students
(F) : 12 students

Success level: 64% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.60

Section 30676
Exam code: quiz05So1L
(A) : 7 students
(B) : 12 students
(C) : 1 student
(D) : 8 students
(E) : 0 student
(F) : 14 students

Success level: 37% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.73

Astronomy quiz archive: sun/spectra/star properties

Astronomy 210 Quiz 5, spring semester 2018
Cuesta College, San Luis Obispo, CA

Section 30674, version 1
Exam code: quiz05NoPw


Section 30674

0- 8.0   :
8.5-16.0 :	* [low = 14.5]
16.5-24.0 :	*****
24.5-32.0 :	****** [mean = 27.6 +/- 7.1]
32.5-40.0 :	******* [high = 40.0]

Section 30676, version 1
Exam code: quiz05So1L


Section 30676

0- 8.0 :	**** [low = 4.0]
8.5-16.0 :	******
16.5-24.0 :	******
24.5-32.0 :	*************** [mean = 24.7 +/- 10.3]
32.5-40.0 :	*********** [high = 40.0]

Astronomy quiz question: star cluster with white dwarfs

Astronomy 210 Quiz 6, fall semester 2017
Cuesta College, San Luis Obispo, CA

A star cluster with white dwarfs would also have __________ at the same time.
(A) massive protostars.
(B) medium-mass main sequence stars.
(C) red dwarfs.
(D) giants.

Correct answer (highlight to unhide): (C)

All stars in a star cluster are born at the same time, but undergo stellar evolution at different rates depending on their masses. Medium-mass stars start out as protostars, then reach their main sequence stage, and subsequently become giants, planetary nebulae, and then white dwarfs. So a star cluster with medium-mass stars in their terminal white dwarf stage would not have the earlier stages of medium-mass stars: main-sequence nor giants.

Since massive stars evolve from protostars much faster than medium-mass stars to reach their main-sequence stage, and then to become supergiants that explode as type II supernovae, none of them will be in their protostar stage in a star cluster where the medium-mass stars have already long ended their main-sequence lifetimes.

Low-mass stars evolve from protostars much slower than medium-mass stars to reach their main-sequence stage to become red dwarfs, and since these low-mass stars have such long main-sequence lifetimes (there have been no red dwarfs that have left the main-sequence since the universe began), and so low-mass red dwarfs can be found in an old star cluster where the medium-mass stars have reached their terminal white dwarf stage.

Section 70158
Exam code: quiz06sSu3
(A) : 5 students
(B) : 19 students
(C) : 9 students
(D) : 10 students

Success level: 25% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.31

Astronomy quiz archive: stellar evolution

Astronomy 210 Quiz 6, fall semester 2017
Cuesta College, San Luis Obispo, CA

Section 70158, version 1
Exam code: quiz06sSu3


Section 70158

0- 8.0 :	*** [low = 7.5]
8.5-16.0 :	****************
16.5-24.0 :	************ [mean = 19.3 +/- 8.0]
24.5-32.0 :	******
32.5-40.0 :	**** [high = 36.5]

Section 70160, version 1
Exam code: quiz06nMuE


Section 70160

0- 8.0 :	* [low = 8.0]
8.5-16.0 :	********
16.5-24.0 :	****** [mean = 23.7 +/- 9.0]
24.5-32.0 :	*********
32.5-40.0 :	********* [high = 36.5]

Astronomy quiz question: stellar evolution states in star cluster

Astronomy 210 Quiz 6, fall semester 2017
Cuesta College, San Luis Obispo, CA

Medium-mass stars in a new star cluster will be in their __________ stage.
(A) protostar.
(B) red dwarf.
(C) white dwarf.
(D) supergiant.

Correct answer (highlight to unhide): (A)

All stars in a star cluster are born at the same time, but undergo stellar evolution at different rates depending on their masses. Medium-mass stars start out as protostars, then reach their main sequence stage, and subsequently become giants, planetary nebulae, and then white dwarfs. So an old star cluster would have medium-mass stars in their white dwarf stage; and a young star cluster would have medium-mass stars still in their protostar stage.

(Response (B) is a low-mass star stage; response (D) is a massive star stage.)

Section 70160
Exam code: quiz06nMuE
(A) : 18 students
(B) : 6 students
(C) : 3 students
(D) : 3 students

Success level: 61% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.64

Astronomy quiz question: least luminous star?

Astronomy 210 Quiz 5, fall semester 2017
Cuesta College, San Luis Obispo, CA

Which star is the least luminous?
(A) M0 red dwarf.
(B) F5 white dwarf.
(C) B0 main sequence star.
(D) B5 supergiant.
(E) (There is a tie.)

Correct answer (highlight to unhide): (B)

An H-R diagram is provided with this quiz.


These stars are plotted on an H-R diagram below. The B5 supergiant is the most luminous, followed by the B0 main-sequence star, the M0 red dwarf, and the F5 white dwarf is the least luminous.


Section 70160
Exam code: quiz05n3Rw
(A) : 11 students
(B) : 13 students
(C) : 0 students
(D) : 0 students
(E) : 4 students

Success level: 49% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 34

Astronomy quiz question: A5 supergiant vs. A5 white dwarf

Astronomy 210 Quiz 5, fall semester 2017
Cuesta College, San Luis Obispo, CA

An A5 supergiant and an A5 white dwarf could have the same:
(A) luminosity.
(B) size.
(C) temperature.
(D) (Two of the above choices.)
(E) (All of the above choices.)
(F) (None of the above choices.)

Correct answer (highlight to unhide): (C)

An H-R diagram is provided with this quiz.


These stars are plotted on an H-R diagram below. While the A5 giant is both larger and more luminous than the A5 white dwarf, they will have the same temperature, as they have the same spectral type.


Section 70158
Exam code: quiz05Sbn3
(A) : 2 students
(B) : 0 students
(C) : 37 students
(D) : 4 students
(E) : 0 students
(F) : 0 students
(No response: 1 student)

Success level: 85% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.50

Section 70160
Exam code: quiz05n3Rw
(A) : 2 students
(B) : 2 students
(C) : 21 students
(D) : 0 students
(E) : 1 student
(F) : 2 students

Success level: 76% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.63