Cuesta College, San Luis Obispo, CA
Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.
The following questions were asked on reading textbook chapters and previewing presentations on parallax, distance, apparent magnitude, absolute magnitude, Wien's law and the Stefan-Boltzmann law.
Selected/edited responses are given below.
Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.
"How we cant really see the stars' size throughout a telescope but yet we are still able to know so much about them from observing its luminosity and temperature."
"I liked how "white-blue" is super-hot--when you think of blue, cold comes to mind."
"In that last slide where it's comparing star sizes, I'm assuming the yellow star is our sun so its crazy to think how many stars are out there that make it look like the size of a peanut!"
Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Is the absolute magnitude what the stars magnitudes actually is? And apparent is what it appears to be? What do they have to do with each other? Why even have an apparent magnitude if that isn't what it actually is?"
"I don't get how the sizes and temperatures work using the Stefan-Boltzmann law."
"I understand the white dwarfs are smaller and it is a star in name, but it's a stellar remnant not undergoing fusion. So isn't technically a red dwarf the smallest star?"
Which star is hottest?
Blue supergiant. ****************** [18] Yellow supergiant. [0] White dwarf. **** [4] Red dwarf. [0] (Unsure/guessing/lost/help!) [0]
Which star is the smallest in size?
Blue supergiant. [0] Yellow supergiant. [0] White dwarf. *********** [11] Red dwarf. ********** [10] (Unsure/guessing/lost/help!) * [1]
Suppose the sun was moved to a distance of 10 parsecs away. As a result, its __________ magnitude would become dimmer.
absolute. ********* [9] apparent. ********** [10] (Both of the above choices.) * [1] (Neither of the above choices.) [0] (Unsure/guessing/lost/help!) ** [2]
Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I was able to tell the time by looking at the moon!"
"Is a white dwarf even technically a star since it's no longer undergoing fusion?" (Well, stars have different names depending on the type of fusion taking place (or not taking place) within: a protostar generates energy from gravitational contraction; a main-sequence star fuses hydrogen in its core; a giant fuses elements heaver than hydrogen up through carbon/oxygen; and a supergiant fuses elements heavier than carbon/oxygen up through iron. So a white dwarf could be said to be a star, but specifically a star that has ended its fusion up through carbon/oxygen.)
"I had miso soup from Sushi Kokku the other day and it was the bomb. They never disappoint."
"How do stellar spectral lines work as star thermometers? How can we actually be sure of a star's temperature?" (From Wien's law, stars' colors tell us temperature. But yes, certain spectral lines can only exist at certain temperatures, and those results of finding temperature from spectral lines confirm the method of finding temperature from color.)
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