Help to fully understand a podcast about spectroscopy

[lesieux]

1. The problem statement, all variables and given/known data

I've recorded an extract of a radio podcast (from Chemistry World) which deals about spectroscopy.
But there are a few points missing in my transcription (I'm French)
Here it is : http://vfsilesieux.free.fr/spectroscopyaudio/audio.swf
I have called (1) to (6) the blanks.


2. Relevant equations

Could anyone help me. It is quite obvious for any native English moreover interested in physics.

3. The attempt at a solution

I've done my best but I need some help.
Thanks in advance.

[t!m]

(1) wavelength ranges
(2) role (?)
(3) regions
(4) lower mass stars
(5) enriching those elements
(6) piece of

[lesieux]

It is very nice of you, thanks a lot.