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Astronomy C

Posted: September 6th, 2016, 9:00 pm
by bhavjain
Short Event Description: Teams will demonstrate an understanding of stellar evolution and Type Ia supernova.

What is a Type 1a supernova, and how does it differ from a Type II supernova?

Re: Astronomy C

Posted: September 6th, 2016, 9:15 pm
by slowpoke
a supernova that occurs in a binary system with one of the bodies being a white dwarf (and the white dwarf is the one going supernova); it is different from a type ii supernova because it contains no hydrogen lines in its spectrum and contains one of silicon

Re: Astronomy C

Posted: September 6th, 2016, 9:26 pm
by bhavjain
Correct! Also, a type II supernova results from the collapse of a massive star's iron core. Your turn.

Re: Astronomy C

Posted: September 8th, 2016, 11:37 pm
by slowpoke
Explain how a type 1a supernova occurs from a double degenerate progenitor.

Re: Astronomy C

Posted: September 9th, 2016, 7:24 am
by bhavjain
slowpoke
Two white dwarfs merge and their combined mass exceeds the Chandrasekhar limit (1.39 solar masses), forming a type 1a supernova.

Re: Astronomy C

Posted: September 9th, 2016, 8:05 pm
by Magikarpmaster629
slowpoke
Two white dwarfs merge and their combined mass exceeds the Chandrasekhar limit (1.39 solar masses), forming a type 1a supernova.
Just want to point out that the Chandrasekhar limit is usually written as ~1.4, since it has variations too great for a significance of 0.01 (although I remember seeing 1.44, not 1.39). This is further complicated by the fact that in some cases white dwarfs can surpass the Chandrasekhar limit without exploding.

Re: Astronomy C

Posted: September 9th, 2016, 8:08 pm
by bhavjain
Magikarpmaster629 I see it as 1.4 as well, but https://en.m.wikipedia.org/wiki/Chandrasekhar_limit says 1.39. What do you mean by significance of .01?

Re: Astronomy C

Posted: September 9th, 2016, 8:27 pm
by slowpoke
slowpoke
Two white dwarfs merge and their combined mass exceeds the Chandrasekhar limit (1.39 solar masses), forming a type 1a supernova.
That is essentially correct! Your turn.
Magikarpmaster629 I see it as 1.4 as well, but https://en.m.wikipedia.org/wiki/Chandrasekhar_limit says 1.39. What do you mean by significance of .01?
I personally use 1.44 after a lot of scourging around online. However, I recently read an article saying that the limit decreases with increasing central density and gravity considerations from ~1.46 so it may be safer to put 1.4 or something else. However, I would say as a general guideline to not trust wikipedia definitively on every number it gives you and to do your own research outside of that.

Re: Astronomy C

Posted: September 12th, 2016, 3:03 pm
by Magikarpmaster629
This QM is severely laking in math...

The system 'Beta Constellationi' contains two stars, A and B. It has a measured trigonomic parallax of 0.03 arcseconds and the angular size of the semi-major axis is 2.93 arcseconds. The system takes 465.5 years to fully orbit.

1. What is the distance to the system in parsecs?
2. What is the actual distance between stars A and B in AU?
3. What is the mass of the system? Give your answer in solar masses.
4. The distance from the center of mass of the system (also known as the barycenter) to star A is 60 AU. What is the distance to star B from the barycenter?
5. What are the individual masses of stars A and B?

Re: Astronomy C

Posted: September 12th, 2016, 3:45 pm
by Unome
This QM is severely laking in math...

The system 'Beta Constellationi' contains two stars, A and B. It has a measured trigonomic parallax of 0.03 arcseconds and the angular size of the semi-major axis is 2.93 arcseconds. The system takes 465.5 years to fully orbit.

1. What is the distance to the system in parsecs?
2. What is the actual distance between stars A and B in AU?
3. What is the mass of the system? Give your answer in solar masses.
4. The distance from the center of mass of the system (also known as the barycenter) to star A is 60 AU. What is the distance to star B from the barycenter?
5. What are the individual masses of stars A and B?
1. 33.33 parsecs
2. 97.66 AU?
3. uhhh... 1148120.12 solar masses? lol
4. 37.66 AU???
5. if 3 and 4 are correct, A = 507518.948 solar masses and A = 640601.172 solar masses (iirc stars don't actually get this big, right?)