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

Astronomy 210, fall semester 2019
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.
"How a low-mass star will take much longer to run out of hydrogen to fuse. How does it take longer, since it's smaller? "

"How a Hummer and SmartCar are able to travel same distance even with the Hummer having a larger tank."

"The lifetimes of the stars. I just find it cool how it's the bigger stars that burn out and die off the quickest compared to the small stars who live on for much longer."

"In a long time the sun will eventually expand into a red giant and that is when Earth will come to an end."

"That a star's mass determines what happens when the star runs out of fuel, and what type of 'corpse' it will become after its death."

"That when a star is about to die it goes into 'starvation' mode."

"Learning more about stars like our own really puts our existence into some perspective."

"That different mass stars die different ways, because I had just assumed that they would just stop glowing, but I was way wrong."

"The types of supernovas/novas, because those were cool images."

"Black holes."

"Black holes are invisible, kinda ominous and scary, but interesting nonetheless."

"The escape velocity of a black hole blows my mind that even light cannot escape."

Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"How convection currents work internally in the stars."

"I'm confused about binary systems and how they keep going even after the nova that occurs from the white dwarf."

"I'm not grasping the different types of supernovas/novas."

"The lighthouse model! What is it trying to explain?"

"Black holes and neutron stars. I don't know the models made a little sense but I think spending a little more time on it and further explanation on it that would help because I am a little lost."

"How a black hole works."

"Nothing in particular."

A Hummer H2 and a SmartCar ForTwo can travel the same distance with a full tank of gas. Briefly explain how this is possible.
"The Hummer H2 has a bigger gas tank but uses it faster. The SmartCar has a smaller gas tank and uses it slower."

"The Hummer has lower mileage than the SmartCar but, it has a bigger fuel tank."

"It's possible because the SmartCar has better fuel efficiency with its smaller tank."

"I honestly don't know; I'm slightly confused."

"Don't know yet."

Match the end-of-life stage with the corresponding main-sequence star.
(Only correct responses shown.)
Black hole: massive main sequence star [76%]
Neutron star: massive main sequence star [59%]
White dwarf: medium-mass main-sequence star [53%]
(No stellar remnant observed yet: low-mass main-sequence star [35%]

Match the type of explosion (if possible) with the corresponding main-sequence star.
(Only correct responses shown.)
Type II supernova: massive main sequence star: [88%]
Type Ia supernova: medium-mass main-sequence star [82%]
Nova: medium-mass main-sequence star [35%]
Low-mass main-sequence star: (no explosion possible) [53%]

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.  * [1]
forever.  ********** [10]
(Unsure/guessing/lost/help!)  *** [3]

The first rule of astronomy class is...

"Ask questions?"

"Earth is flat?"

"To build telescopes?"

"Come to each and every class?"

"Dome prepared and ready to learn?"

"Look up at the stars, because that is where the answers are?"

"You do not talk about astronomy class.' (Fight Club, 1999)"

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"How are cars related to astronomy?"

"For a medium-mass star, how come the convection current doesn't work in the similar way a low mass star works?" (Convection is a surface effect for a star, so for a medium-mass or massive star, convection (the "miso soup effect") is right at the "skin" of those stars. However, for a low mass star, it is so small that the "skin" and core are basically touching, such that the convection currents are able to affect the core.)

"What is space-time and how can gravity affect it?"

"I'd like to go over black holes a bit more."

"Will we get into black holes more or will we just get a brief talk about them?

"Have humans ever sent anything into a black hole?" (No, but we have observed stars being shredded apart as they get too close, and their material falls in towards black holes.)

"Can you please go over these slides in class, there was a lot, thank you."

No comments: