Astronomy C

[youngswimmer]

hey i just wanted to coment that my mentor name for this is buzz... when i asked him what his last ame was he didnt say lightyear i got ver sad.

[syo_astro]

hey i just wanted to coment that my mentor name for this is buzz... when i asked him what his last ame was he didnt say lightyear i got ver sad.

Okay, just to note try to make more appropriate questions/comments relating to the event in the future . Though, personally I thought of Aldrin first XD. But I think this is more of a post for general chat/posting games. So, just a note for the future.

Now, since this hasn't been so active (hehe, AGNs), I guess I will ask a question or two (or more...). What do people have for the period-luminosity relationship for cepheid variables? I have two equations:
Mv=-2.81log(P) - (1.43 +/- 0.1)
And:
Mv=-2.43 +/- 0.12(log(P)-1) - (4.05 +/- 0.02)
Where, Mv is the absolute magnitude of the cepheid, P is period of course.
Also, I can't remember, is the relationship only for Type I cepheids? Is there one for Type II, or is it just expected to use the graphs to approximate? Does the +/- matter so much; does it just indicate variability? Sorry, I just can't totally tell from what I've been reading.

Wow, tryouts coming up for me, so hopefully I get the event again

[flutest]

im not vey good with memorizing stuff does anybody have good techniques?
im division b so i doing reach for the stars.

[syo_astro]

im not vey good with memorizing stuff does anybody have good techniques?
im division b so i doing reach for the stars.

Just to direct the question more appropriately the topic for reach for the stars is here:
http://www.scioly.org/phpBB3/viewtopic. ... 2&start=15

As a general recommendation I say my post on the last page still somewhat applies in the fact of read the rules, google every part to it, look at the scioly wiki (for reach that is), and the current forum topic (which I linked) and past ones. It's hard work, but if you spend the time you can do it . I think I hear going out and trying to observe the stars if you can helps. Hope this helps...but try your question at the reach forum there.

Now, I still am hoping someone can answer my own question above...

[flutest]

ya i know im new a round hear and didnt see the thing for it. sorry. but thanks for the help.

im not vey good with memorizing stuff does anybody have good techniques?
im division b so i doing reach for the stars.

Just to direct the question more appropriately the topic for reach for the stars is here:
http://www.scioly.org/phpBB3/viewtopic. ... 2&start=15

As a general recommendation I say my post on the last page still somewhat applies in the fact of read the rules, google every part to it, look at the scioly wiki (for reach that is), and the current forum topic (which I linked) and past ones. It's hard work, but if you spend the time you can do it . I think I hear going out and trying to observe the stars if you can helps. Hope this helps...but try your question at the reach forum there.

Now, I still am hoping someone can answer my own question above...

[XJcwolfyX]

*Yeah *I'm *around *here *didn't *thread (not thing!) Lol sorry for correcting you . . . .

Anyways, lol, what are the formulae we need to know for the event, and are there any websites with all of them?

[EastStroudsburg13]

There's a formula sheet on the bottom of the Astronomy Wiki. There might be more that you will encounter as you research, but it's a good place to start.

[desmond the moonbear]

how do you get the answers to the tiebreakers?

[EastStroudsburg13]

By knowing them beforehand.

It depends a lot on what the tiebreaker is. It can literally be anything. It doesn't even have to be astronomy-related (although ideally it would be). In order for me, or anyone else, to give you better assistance, we'd need to know the question.

[AlphaTauri]

Now, since this hasn't been so active (hehe, AGNs), I guess I will ask a question or two (or more...). What do people have for the period-luminosity relationship for cepheid variables? I have two equations:
Mv=-2.81log(P) - (1.43 +/- 0.1)
And:
Mv=-2.43 +/- 0.12(log(P)-1) - (4.05 +/- 0.02)
Where, Mv is the absolute magnitude of the cepheid, P is period of course.
Also, I can't remember, is the relationship only for Type I cepheids? Is there one for Type II, or is it just expected to use the graphs to approximate? Does the +/- matter so much; does it just indicate variability? Sorry, I just can't totally tell from what I've been reading.

Hm, according to Wiki, the second eq is derived from HST observations of Type I Cepheids, and according to C/O the first eq is supposed to be for Type Is (calculated by HIPPARCOS), so that's good. But C/O also gives Mv = -3.53logP - 2.13 + 2.13(B-V).

I haven't really found any PLRs for Type IIs, however, according to C/O, Type IIs are about 4 times or 1.5 magnitudes fainter than Type Is, so you could just calculate it like a Type I and subtract 1.5 mags. Also, this site gives the following eqs:
Population I: Mv = -2.81 logP - 1.43
Population II: Mv = -2.81 logP + 0.15

Edit: Whoops, realized I made a major mistake. We're good now.