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Re: Astronomy C
Posted: March 8th, 2012, 5:17 pm
by Osennecho
AlphaTauri wrote:I seem to have lost or otherwise neglected to save the original page of links (oops), but as I recall, most of the links were useless and/or broken anyways. Here's some of the better courses I pulled off of that site:
Ohio State,
University of Tennessee, and
UC San Diego.
Osennecho wrote:I need new information to read... The same repetitive material in all the textbooks I have isn't useful enough for the PA regional/state astro tests (By far hardest tests I have ever taken in science olympiad all invitationals included).
I'm with ya on that, though it's worse for you since the guy who writes for States also writes the SE test. Last year at States, my partner and I were completely blown away by how tough the test was - we couldn't even answer the first question! (But at least now it's forever ingrained in my mind that the "MACS" in MACSJ0717.5+3745 stands for MAssive Cluster Survey). Heh, scores were funny though - 1st and 2nd place were in the 70s or low 80s on a 100-point test, 3rd place...was around 25...and then the 33 remaining teams must've scored within a 24-point spread...
Are you serious about that point spread? Or sarcasm... It seriously could be either... If true I feel a bit better about this year... Long story behind why so I won't bother to type it
...
Re: Astronomy C
Posted: March 10th, 2012, 12:39 pm
by HannahD413
Can someone help double check the answer to this question?
19. Supernova 2011fe was one of the best this year. What is the distance to it in Megaparsecs? Its light curve is shown below
a) 7.1 Mpc
b) 83 Mpc
c) 692 Mpc
d) 46 Mpc
e) .52 Mpc
The light curve is shown to peak at an apparent magnitude of about 10. The answer key says b, and the note on the key says:
Peak apparent magnitude = 10. Absolute magnitude of type Ia supernovae=-19.6. Use distance modulus: Dist(pc)=10*10^(m-M/5)=10*10^((10.19.6)/5)
However, if the distance modulus equation that I have seen everywhere else, m-M=-5+5logd, is used, it doesn't work. Am I doing something stupid wrong?
Re: Astronomy C
Posted: March 10th, 2012, 12:46 pm
by manutd94
Your formula m-M = -5 + 5log(d) should work. I believe the key might be off by one magnitude (83 is what they have as opposed to 8.3 Mpc).
Re: Astronomy C
Posted: March 10th, 2012, 1:40 pm
by FullMetalMaple
When I worked the problem, I got 83 Mpc... I used the rearranged form of the distance modulus, though (d = 10^(m - M + 5)/5).
EDIT: Never mind. I put that in wrong.
Re: Astronomy C
Posted: March 10th, 2012, 1:47 pm
by pjgscioisamazing
FullMetalMaple wrote:When I worked the problem, I got 83 Mpc... I used the rearranged form of the distance modulus, though (d = 10^(m - M - 5)/5).
The rearranged distance modulus equation is d = 10^((m-M+5)/5)
Re: Astronomy C
Posted: March 10th, 2012, 1:57 pm
by FullMetalMaple
pjgscioisamazing wrote:FullMetalMaple wrote:When I worked the problem, I got 83 Mpc... I used the rearranged form of the distance modulus, though (d = 10^(m - M - 5)/5).
The rearranged distance modulus equation is d = 10^((m-M+5)/5)
Yeah... that was a dumb mistake. Thanks for catching it.
Re: Astronomy C
Posted: March 10th, 2012, 2:19 pm
by HannahD413
If you use 19.6 as the magnitude (rather than 19.3, which is what we were using during the competition), I can see how you get 8.3 Mpc, but not 83. -5+5log(83*10^6)=35.6 which does not equal 10+19.6=29.6, -5+5log(8.3*10^6) does however.
Re: Astronomy C
Posted: March 12th, 2012, 7:24 pm
by pihi
In the rules document it says that you can bring laptops. Does that mean each team member gets to bring a laptop or is it just one per team? At regionals, the judge was pretty strict and said that each team was only allowed one laptop.
Re: Astronomy C
Posted: March 12th, 2012, 7:31 pm
by AlphaTauri
You can bring a laptop or a three-ring binder per person. So if you really wanted to, yes, you could bring two laptops...although it'd be kind of redundant, since with the amount of storage most laptops have (or with the addition of a flash drive or external HD), you could just put all the info on one laptop and have a binder for quick info.
For future reference, if you get a judge like that in the future, you are allowed to politely point out - preferably with rules in hand - that they're not running the event right. Typically it works best if you're part of the first group to go for the event, since they're less likely to change the way they're running the event if people have already competed with the handicap.
Re: Astronomy C
Posted: March 12th, 2012, 7:48 pm
by pihi
AlphaTauri wrote:You can bring a laptop or a three-ring binder per person. So if you really wanted to, yes, you could bring two laptops...although it'd be kind of redundant, since with the amount of storage most laptops have (or with the addition of a flash drive or external HD), you could just put all the info on one laptop and have a binder for quick info.
For future reference, if you get a judge like that in the future, you are allowed to politely point out - preferably with rules in hand - that they're not running the event right. Typically it works best if you're part of the first group to go for the event, since they're less likely to change the way they're running the event if people have already competed with the handicap.
Ok thank you! And the reason we wanted two laptops was because the test was two separate sheets and we thought it would be quicker with two laptops so each partner could do half of the test