Astronomy C

[syo_astro]

There was a question that came up today that I remember also came up a while ago, but I wasn't quite able to dig it up from my notes.

"This object contains many Type II Supernovae remnants along with many Class O stars" (or something to that effect).

Was it in relation to a DSO, or was it just some general type of object? Maybe it could relate to an OB assocation?

[Asteroidea]

If you have the latitude of the city and the declinations of the objects, you can determine the maximum altitude. In the northern hemisphere, it is possible to see objects with a declination of greater than the latitude minus 90 degrees, or in the southern hemisphere, (with a negative latitude sign) a maximum of the latitude plus 90 degrees.

I'm still slightly confused...say my latitude is 41 and I'm using one of the DSOs from this year, Mira, which has a right ascension of 02h 19m 20.79210s and a declination of –02° 58′ 39.4956″ and I'm in the Northern Hemisphere...How would I go about doing it?

Would I take 90-41 to get 49 which is my co-latitude
and then add my co-latitude to my declination which would be 49-2=47
and soooo...it should theoretically be visible sometime during the year?
I used this to help me-> http://kvmagruder.net/bcp/sphere/d.htm

Am I doing this correct? Thanks!

[darkwinters]

There was a question that came up today that I remember also came up a while ago, but I wasn't quite able to dig it up from my notes.

"This object contains many Type II Supernovae remnants along with many Class O stars" (or something to that effect).

Was it in relation to a DSO, or was it just some general type of object? Maybe it could relate to an OB assocation?

It was a DSO.

[Schrodingerscat]

I'm still slightly confused...say my latitude is 41 and I'm using one of the DSOs from this year, Mira, which has a right ascension of 02h 19m 20.79210s and a declination of –02° 58′ 39.4956″ and I'm in the Northern Hemisphere...How would I go about doing it?

Would I take 90-41 to get 49 which is my co-latitude
and then add my co-latitude to my declination which would be 49-2=47
and soooo...it should theoretically be visible sometime during the year?
I used this to help me-> http://kvmagruder.net/bcp/sphere/d.htm

Am I doing this correct? Thanks!

That looks correct.

[Asteroidea]

So as long as that final number is below 90 it should be visible right?

[AlphaTauri]

There was a question that came up today that I remember also came up a while ago, but I wasn't quite able to dig it up from my notes.

"This object contains many Type II Supernovae remnants along with many Class O stars" (or something to that effect).

Was it in relation to a DSO, or was it just some general type of object? Maybe it could relate to an OB assocation?

It was a DSO.

My best guess would be Trapezium, like Mr. Cicc said -- a bright cluster of O/B stars and many young protostars. Definitely conceivable that some are forming from the remnants of the more massive stars in the cluster.

There is also a remote possibility that it could be attempting to refer to Eta Carinae, though it's a bit of a stretch as the question would have to be referring to the entire Carina Nebula instead of Eta Car itself.

[Tiktaalik]

Does anyone know where a good complete list of all the objects in the Henry Draper catalogue can be found? I've been able to find most of the other important star catalogues we might need to use.

[Smithy0013]

So why use B-V index to find temperature of a star when you can use Wien's law? What is the point of B-V index besides finding Temp?

[Schrodingerscat]

So why use B-V index to find temperature of a star when you can use Wien's law? What is the point of B-V index besides finding Temp?

For one, from an observational standpoint, one can measure B-V index with just two magnitude measurements with a B and a V filter, as opposed to needing a full spectrometer to use Wien's law. Otherwise, it is just another way to measure temperature/color of a star to my knowledge.

[astro124]

So why use B-V index to find temperature of a star when you can use Wien's law? What is the point of B-V index besides finding Temp?

For one, from an observational standpoint, one can measure B-V index with just two magnitude measurements with a B and a V filter, as opposed to needing a full spectrometer to use Wien's law. Otherwise, it is just another way to measure temperature/color of a star to my knowledge.

Isn't Wien's law more common to use (at least on Scioly tests)? On my state test a few weeks ago I remember seeing two maximum wavelength to temperature problems but zero B-V color index questions. That being said, you'll regularly see B-V color on the X-axis of H-R diagrams.

Also, can anybody help me with a quick binary system question. When I went to take the Arizona astro test there were two questions were they gave us the velocity of a binary system, the average rotational period of the two objects, and the mass of one of the objects. From there they asked us to calculate the mass of the second object. Thanks!