Testing, testing...

[northward]

Okay, so I've been reading up on spectral type and luminosity and wanted to give this a whirl.  

I recently started a journal, and the first constellation I noted, a familiar one, was Cassiopeia.  I noted the stars and used Stellarium to aid in getting names, and further information.  I noted Caph.  It is an F2III star.  I used that as my example.  So, I want to explain why it is an F2III and hopefully you guys can check my explanation to see if I actually understand this stuff.  

 

So, it is classified F due to the temperature of the star, which is in the mid-range.  It also gets a classification of 2, out of 9, to indicate further details about its temperature.  Then, it falls into the category of III for luminosity because it's absorption bands indicate that it is a normal giant in size.

Does this make sense? I know it isn't very very specific, as if I were a true astronomer, but this is my understanding of the classification systems so far. 

 

 

[cloudsweeper]

The starting letter (O,B A,F,G,K,E) relates to spectra and temperature, followed by a number (0 - 9) indicating relative position in that particular section/spectrum.  The final Roman Numeral (I to VII) relates to luminosity.  So yes, you've got it right.

Can't claim any glory for this! - See http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml - which explains it all very well.

Doug.

 

[northward]

Thanks for the link cloudsweeper, there's tons to look at there.

 

A further question,  if you view Polaris, a cepheid variable star, can you actually witness it pulsating? Or is that detail too far away?  OR does it not pulsate rapidly enough?

[cloudsweeper]

9 minutes ago, northward said:

Thanks for the link cloudsweeper, there's tons to look at there.

 

A further question,  if you view Polaris, a cepheid variable star, can you actually witness it pulsating? Or is that detail too far away?  OR does it not pulsate rapidly enough?

Don't know a lot about the topic except that Cepheid Variables are used as standard candles for gauging astronomical distances.  They pulsate over days/several days, so you wouldn't actually see the effect with one in your EP.  And I believe some of them, if observed over a long enough period, would show a noticeable variation in stellar magnitude.

Hope this helps - I'm only a dabbler in these matters!

Doug.