Showing posts with label main sequence star. Show all posts
Showing posts with label main sequence star. Show all posts
20211122
Sketchbook: low-mass stars
The sun introduces some other low-mass stars. Also, the sun's expressions pretty much sums up how I feel about things right now.
Somehow I associate "low-mass" with "low-key."
20160504
Astronomy in-class activity: monolithic collapse hypothesis, stellar populations
Astronomy 210 In-class activity 22 v.16.05.04, spring semester 2016
Cuesta College, San Luis Obispo, CA
Students find their assigned groups of three to four students, and work cooperatively on an in-class activity worksheet to discuss different metallicities and ages of stars in the monolithic collapse hypothesis of the Milky Way.
Cuesta College, San Luis Obispo, CA
Students find their assigned groups of three to four students, and work cooperatively on an in-class activity worksheet to discuss different metallicities and ages of stars in the monolithic collapse hypothesis of the Milky Way.
20150109
Astronomy in-class activity: star cluster age
Astronomy 210 In-class activity 18 v.15.01.09, spring semester 2015
Cuesta College, San Luis Obispo, CA
Students find their assigned groups of three to four students, and work cooperatively on an in-class activity worksheet on comparing evolution rates of different-mass stars, and ranking relative star cluster ages given their H-R diagrams.
Cuesta College, San Luis Obispo, CA
Students find their assigned groups of three to four students, and work cooperatively on an in-class activity worksheet on comparing evolution rates of different-mass stars, and ranking relative star cluster ages given their H-R diagrams.
20130611
Astronomy in-class activity: stellar evolution stages
Astronomy 210 In-class activity 19 v.13.06.11, fall semester 2013
Cuesta College, San Luis Obispo, CA
Students find their assigned groups of three to four students, and work cooperatively on an in-class activity worksheet on the different evolutionary tracks of different mass stars.
Cuesta College, San Luis Obispo, CA
Students find their assigned groups of three to four students, and work cooperatively on an in-class activity worksheet on the different evolutionary tracks of different mass stars.
20090619
TireWriter(TM): spiral arm formation model
http://www.flickr.com/photos/waiferx/3567609008/
Originally uploaded by Waifer X
TireWriter(TM), from Schwinn, demonstrating how density waves create the spiral arm structure of the Milky Way. Massive main-sequence stars are luminous and short-lived, and thus are only seen where their formation is triggered. Video by Cuesta College Physical Sciences Division instructor Dr. Patrick M. Len.
20081103
Astronomy quiz question: evolution to stellar remnants
Astronomy 210 Quiz 5, Fall Semester 2008
Cuesta College, San Luis Obispo, CA
[Version 1]
[4.0 points.] Which type of main-sequence star will eventually become a neutron star?
(A) Massive.
(B) Medium-mass.
(C) Low-mass.
(D) (None of the above choices.)
Section 70158
(A) : 34 students
(B) : 16 students
(C) : 8 students
(D) : 8 students
Correct answer: (A)
"Mass is destiny." Massive stars will become either neutron stars, or black holes; medium-mass stars will become white dwarfs, while low-mass stars become (and remain) red dwarfs, at least for now, given the current age of the universe.
"Difficulty level": 54%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.95
[Version 2]
[4.0 points.] Which type of main-sequence star will eventually become a white dwarf?
(A) Massive.
(B) Medium-mass.
(C) Low-mass.
(D) (None of the above choices.)
Section 70160
(A) : 0 students
(B) : 20 students
(C) : 5 students
(D) : 5 students
Correct answer: (B)
"Difficulty level": 69%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.42
Cuesta College, San Luis Obispo, CA
[Version 1]
[4.0 points.] Which type of main-sequence star will eventually become a neutron star?
(A) Massive.
(B) Medium-mass.
(C) Low-mass.
(D) (None of the above choices.)
Section 70158
(A) : 34 students
(B) : 16 students
(C) : 8 students
(D) : 8 students
Correct answer: (A)
"Mass is destiny." Massive stars will become either neutron stars, or black holes; medium-mass stars will become white dwarfs, while low-mass stars become (and remain) red dwarfs, at least for now, given the current age of the universe.
"Difficulty level": 54%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.95
[Version 2]
[4.0 points.] Which type of main-sequence star will eventually become a white dwarf?
(A) Massive.
(B) Medium-mass.
(C) Low-mass.
(D) (None of the above choices.)
Section 70160
(A) : 0 students
(B) : 20 students
(C) : 5 students
(D) : 5 students
Correct answer: (B)
"Difficulty level": 69%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.42
20081102
Astronomy quiz question: red dwarfs as giants?
Astronomy 210 Quiz 5, Fall Semester 2008
Cuesta College, San Luis Obispo, CA
A red dwarf will never become a giant because:
(A) it is made of degenerate matter.
(B) its core will never get hot enough to fuse helium.
(C) it will never run out of hydrogen to fuse.
(D) not a single red dwarf has died of old age anywhere in the universe.
Correct answer: (B)
A red dwarf has a main sequence lifetime much longer than the age of the universe, so none have actually "died" yet. However, when all of the hydrogen in a red dwarf has been depleted, it will gravitationally contract, but not enough to increase the temperature for helium to fuse, so it will never restart fusion to become a giant, as a medium mass main sequence star would at the end of its hydrogen fusion lifetime.
Section 70158
(A) : 2 students
(B) : 51 students
(C) : 6 students
(D) : 7 students
"Success level": 80%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22
Section 70160
(A) : 1 student
(B) : 16 students
(C) : 8 students
(D) : 5 students
"Success level": 58%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.31
Cuesta College, San Luis Obispo, CA
A red dwarf will never become a giant because:
(A) it is made of degenerate matter.
(B) its core will never get hot enough to fuse helium.
(C) it will never run out of hydrogen to fuse.
(D) not a single red dwarf has died of old age anywhere in the universe.
Correct answer: (B)
A red dwarf has a main sequence lifetime much longer than the age of the universe, so none have actually "died" yet. However, when all of the hydrogen in a red dwarf has been depleted, it will gravitationally contract, but not enough to increase the temperature for helium to fuse, so it will never restart fusion to become a giant, as a medium mass main sequence star would at the end of its hydrogen fusion lifetime.
Section 70158
(A) : 2 students
(B) : 51 students
(C) : 6 students
(D) : 7 students
"Success level": 80%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.22
Section 70160
(A) : 1 student
(B) : 16 students
(C) : 8 students
(D) : 5 students
"Success level": 58%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.31
20081022
Astronomy quiz question: blue main sequence star vs. blue supergiant
Astronomy 210 Quiz 4, Fall Semester 2008
Cuesta College, San Luis Obispo, CA
[4.0 points.] A blue main sequence star is known to be smaller than a blue supergiant because it is:
(A) same temperature as, but more luminous than a blue supergiant.
(B) same temperature as, but less luminous than a blue supergiant.
(C) same luminosity as, but hotter than a blue supergiant.
(D) same luminosity as, but cooler than a blue supergiant.
Section 70158
(A) : 9 students
(B) : 50 students
(C) : 8 students
(D) : 2 students
Correct answer: (B)
From Wien's law, the main sequence star and the supergiant must have the same temperature, because they have the same color. From the Stefan-Boltzmann law, for two stars of the same temperature, the less luminous star must be smaller in size.
"Difficulty level": 75%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.38
Cuesta College, San Luis Obispo, CA
[4.0 points.] A blue main sequence star is known to be smaller than a blue supergiant because it is:
(A) same temperature as, but more luminous than a blue supergiant.
(B) same temperature as, but less luminous than a blue supergiant.
(C) same luminosity as, but hotter than a blue supergiant.
(D) same luminosity as, but cooler than a blue supergiant.
Section 70158
(A) : 9 students
(B) : 50 students
(C) : 8 students
(D) : 2 students
Correct answer: (B)
From Wien's law, the main sequence star and the supergiant must have the same temperature, because they have the same color. From the Stefan-Boltzmann law, for two stars of the same temperature, the less luminous star must be smaller in size.
"Difficulty level": 75%
Discrimination index (Aubrecht & Aubrecht, 1983): 0.38
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