Astronomy

[EastStroudsburg13]

So up to what level of math do you need for this? Is pre-calc sufficient?

[eak227]

I've never seen calculus on a test. All I can think of would be solving systems of equations and such. So yeah, pre-cal should cover it... It's basically just knowing which equations to use and how to solve them if I remember right.

[EastStroudsburg13]

Cool! That's a really big relief.

[Glacierguy1]

http://www.tufts.edu/as/wright_center/p ... astro.html

On the Penn.States 2008 test at this link, I have been doing problem # 82 for the past hour and a half and cannot figure for the life of me how he got 235 parsecs as the answer. I get 2.35 parsecs every time, and I cannot figure out where that extra 100 factor went.

Please help!

[Flavorflav]

I get 2.35 pc, too. I think it's just a mistake.

[Glacierguy1]

Thanks.

What about these ones.

15)
Star C and Star D have equal masses, luminosities, and spectral classes. They are also members of a spectroscopic binary star system that is observed to have a separation of 6.0 x 107 km and a period of 10.0 days. What is the orbital velocity of Star C (in km/s)?
16)
In the spectrum for Star C, the Hα was measured to have a wavelength of 656.5386 nm compared with a laboratory value of 656.3000 nm. What is the angle between the plane of the systems orbit and the line of sight of the observer (in degrees)?

From last years nationals test if anyone cares.



Edit: I keep getting 109 ish for 15 and I have no clue for 16 at all.















Answers: 15. 200-236 km/s
16. 50-70 degrees

[Flavorflav]

On the third try I got 218 for #15, but I get 39 degrees for #16.

Hey, just noticed that 218 is double 109. You are probably just dropping a two someplace. IDK what's wrong with #16.

[Glacierguy1]

Yeah, I figured that for 15, but I have no clue where that two went.

[Flavorflav]

I think I figured out #16. I sined when I should have cosined - with cos I get 51 degrees.

[Glacierguy1]

Please explain.