Astronomy C

[JCicc]

PM is fine, or you can post it right here. Whatever you prefer.

[JCicc]

Southeastern PA regional exam is up on the test exchange.

[lmatkovic3]

Thanks again for the state test. My partner spent an hour doing it and two hours going over it, adding to our notes and whatnot. We did notice, however, a typo in the key. On question #45, the key says the answer is 1.5 magnitudes, but amplitude is defined as half the distance between crest and trough, so we think it should be ~.7 magnitudes.

[syo_astro]

Thanks again for the state test. My partner spent an hour doing it and two hours going over it, adding to our notes and whatnot. We did notice, however, a typo in the key. On question #45, the key says the answer is 1.5 magnitudes, but amplitude is defined as half the distance between crest and trough, so we think it should be ~.7 magnitudes.

I guess maybe Cicc should explain his thoughts/whether you are right or not, but I thought since it was implying the whole pulsation sort of it was ~1.5.

[JCicc]

I thought the amplitude for a cepheid was the difference in magnitude at maximum and minimum. I see what you are saying in terms of mechanical wave theory, but the only evidence I can provide is that delta Cep is described as having an amplitude of nearly 1 mag, and it ranges from about 3.6 to about 4.4.

[lmatkovic3]

I thought the amplitude for a cepheid was the difference in magnitude at maximum and minimum. I see what you are saying in terms of mechanical wave theory, but the only evidence I can provide is that delta Cep is described as having an amplitude of nearly 1 mag, and it ranges from about 3.6 to about 4.4.

That makes sense. I just wasn't sure of the explanation when I was going over our missed questions with my partner. Thank you!

[BYHscioly]

Do we need to know any hard astrophysics? Like aside from parallax, Stefan-Boltzmann's, distance modulus, redshift, Wien's, etc.?

[syo_astro]

Do we need to know any hard astrophysics? Like aside from parallax, Stefan-Boltzmann's, distance modulus, redshift, Wien's, etc.?

By that are you asking whether for nats you need to know about astronomical math? I would say definitely know those. I think before on the forums some things have been mentioned. On the wiki there is an equation sheet (that's only meant to act as some examples, I recommend copying it, but definitely edit it and add to it to your liking). Cicc's test also has some very nice math on X-ray binaries, cepheids, and pulsars if I recall. Some nats tests are available online either on the test exchange or elsewhere. Any areas you're worried about specifically?

[BYHscioly]

I was just hoping there wouldn't be any of that college physics stuffs.

Are the scores for the PA tests released? If so, are they online? We took a practice test so...

[AlphaTauri]

If you want, you can PM the PA State writer, Mr. Cicc (JCicc on the forums), to ask for scores; I don't know if he wants them posted publicly.

I think, however, that I'm allowed to tell you that the high score this year was a 74, with the Top 5 stretching down to 60. Last year's high score was an 88, with the Top 5 down to 58.