Query about brightness ratio chromosphere and photosphere

Got a beginners' question? No matter how elementary, our friendly forum community and magazine writers will answer it.

Query about brightness ratio chromosphere and photosphere

Postby tim.tlz » Thu Mar 09, 2017 4:22 pm

Hi Everyone

I would be very grateful if someone could answer this question for me.

If you divide the brightness of the uneclipsed photosphere of the sun by the brightness of the chromosphere that can be seen around a totally eclipsed sun, what is the result? (Obviously when I use the word "chromosphere", this should not be confused with the corona.)

I am having difficulty finding the necessary information on the Internet in order to answer this question myself. That is why I am asking this forum.

Thank you very much.

Kind regards

Tim
tim.tlz
 
Posts: 5
Joined: Wed Aug 10, 2016 5:30 pm

Re: Query about brightness ratio chromosphere and photospher

Postby Gfamily2 » Thu Mar 09, 2017 11:54 pm

The nearest to any quantitative data I've found is a vague claim that the luminosity is proportional to the density, which would (if that was all that's going on), mean that the brightness of the chromosphere would be about 1/10,000 that of the photosphere.
However, because the photosphere light is continuous spectrum while the chromosphere light is emission lines, I don't think we can make that assumption.

Interestingly, the light emitted by the chromosphere is the same as the light absorbed by the Fraunhofer lines in the sun's spectrum, so if you can put a value to the extent that the Fraunhofer lines deduct from the black body profile that will be your result.

Only conceptual help I'm afraid
Scopes: Meade 8" SCT, Skywatcher 127mm Mak
For imaging: Pentax K5, Asda webcam, Star Adventurer (new toy)
For companionship: Mid Cheshire Astronomical Group.
Gfamily2
 
Posts: 253
Joined: Thu Jun 25, 2015 10:38 pm

Re: Query about brightness ratio chromosphere and photospher

Postby The Man with the Corrugated Iron Roof » Sun Mar 19, 2017 1:26 am

The Chromosphere is about magnitude -14 and the photosphere is about -27, so that's 13 magnitude difference. So if you can calculate 2.512 to the power of 13, that's the answer!
How can I be one with the universe when we don't know what 96% of it is.

My website: http://www.philippughastronomer.com/

My blog: http://sungazer127mak.blogspot.co.uk/2015/11/november-2015.html
The Man with the Corrugated Iron Roof
 
Posts: 349
Joined: Sat Nov 23, 2013 1:53 pm
Location: Wiltshire but can be just about anywhere up to 41 000 feet


Return to Ask a silly (astronomy) question

Who is online

Users browsing this forum: No registered users and 0 guests