20181106

Online reading assignment: medium-mass stars, massive stars, neutron stars and black holes (NC campus)

Astronomy 210, fall semester 2018
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 the evolution of medium-mass stars, massive stars, neutron stars and black holes.


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.
"The way that a massive star dies in supernova. How it all implodes first then explodes is amazing. how all that energy is sucked in then bounced off into space. I'm sure it is a real awesome thing to witness."

"How two twin stars can be born but have different rates because of their masses."

"Stages of life stars go through. Like what happens before, during, and after."

"Differences between the three types of novae: nova, type Ia supernova, and type II supernova."

"Black holes! I thought it was cool how it's kind of like the Lake Berryessa dam intake but obviously much more complex."

"Learning about black holes since I have no idea what they really are or how they work."

"The fate of the sun and the stars, because now I'm curious if the universe could remake what we have now before they all die."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"How stars are not like cars?"

"Evolution of binary system stars because I'm not sure about the transferring of mass."

"I would just like a review of how binary pulsars work."

"Black holes seem pretty confusing like how time and space is messed up."

A Hummer H2 and a SmartCar ForTwo can travel the same distance with a full tank of gas. Briefly explain how this is possible.
"One has a larger tank then the other, although the rate at which they use gas is different as well. One uses it quicker then the other."

"The SmartCar will use it smaller amount of fuel more economical. It will burn its fuel at a slower rate thus be able to travel the same distance as a larger Hummer."

"I need to read the material."

Match the end-of-life stage with the corresponding main-sequence star.
(Only correct responses shown.)
Black hole: massive main sequence star [90%]
Neutron star: massive main sequence star [40%]
White dwarf: medium-mass main-sequence star [50%]
(No stellar remnant observed yet: low-mass main-sequence star [40%]

Match the type of explosion (if possible) with the corresponding main-sequence star.
(Only correct responses shown.)
Type II supernova: massive main sequence star: [70%]
Type Ia supernova: medium-mass main-sequence star [10%]
Nova: medium-mass main-sequence star [80%]
Low-mass main-sequence star: (no explosion possible) [40%]

If you were to leap into a black hole, your friends would typically watch you falling in for __________ before you entered the event horizon.
seconds.  ** [2]
hours.  * [1]
days.  [0]
a year.  [0]
many years.  ** [2]
forever.  **** [4]
(Unsure/guessing/lost/help!)  * [1]

The first rule of astronomy class is...
"Do your reading and follow the stars?"

"Show up prepared?"

"Do the reading?"

"Try?"

"Acquire knowledge?"

"Come to class?"

"To have fun?"

"Show up with a positive attitude?"

"Do your homework?"

"You do not talk about astronomy class."

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Thank you for making the slides and class interesting enough that it keeps me intrigued."

"I still don't understand why stars cannot pull more hydrogen from the space around it to feed itself for much longer than it does?" (The solar winds from a star during its main sequence (hydrogen fusion) lifetime typically pushes away any hydrogen nearby, clearing the space around it. However, that star can be fed by a comparing star as that companion star expands into a giant or subsequently a planetary nebula, as those hydrogen layers are pushed outwards from it to feed that star.)

"When a star explodes, the outer shell of the star is shed into interstellar space. Since there would only be elements from fusion no heavier that iron, where would a protostar and ultimately its solar system get any heavier elements?" (Even though fusion to produce elements heavier than iron requires energy instead of releasing energy, in a type II supernova explosion as the shell implodes and explodes there is lots of extra energy that can enable fusion to go past iron.)

"Nothing to ask this week."

"I love learning about black holes."

"Give me time. I'll catch up."

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