Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Fe I multiplets in K type stars with the Star Analyser

  • Please log in to reply
2 replies to this topic

#1 mwr

mwr

    Ranger 4

  • -----
  • topic starter
  • Posts: 308
  • Joined: 12 May 2018

Posted 07 May 2021 - 03:36 PM

K type stars show an intimidating number of atomic lines in their spectra and are not good objects for low resolution spectroscopy using the Star Analyser. Nevertheless, I have tried to resolve some multiplets of the alkali and alkaline earth metals in the spectrum of Algieba (gamma Leonis). Surprisingly, the resolution in the UV and NIR region was quite good (around 10 A; the Bayer colour filter array of my colour camera Canon EOS 450 Da becomes transparent in these regions) and this allowed to partially resolve some of the Fe I multiplets in the UV:

 

Folie1.JPG

 

Fe I shows an extremely complex spectrum with many lines as illustrated already by a partial (!) Grotrian diagram :

 

Folie2.JPG

 

The notation used for the terms in this diagram is quite different form the terms used in the Grotrian diagrams of the alkali and alkaline earth metals, and I had to consult the primary literature.  A very helpful publication is “A new muliplet table for Fe I” http://adsabs.harvar...ApJS...94..221N together with the NBS technical note “A multiplet table of astronomical interest” https://play.google....=de&pg=GBS.PA13. This has allowed to fully assign the Fe I multiplet no. 43 with its satellites between the G band and the Ca II doublet:

 

Folie3.JPG

 

Of course, high resolution spectra show that most of these multiplets are actually complex blends with lines of other elements and molecules, but it is a nice exercise for cloudy nights in the Corona lock-down. One question remains to be answered: why did the authors used the old written German letter “z” for the notation of some selected terms in the Fe I Grotrian diagram? Perhaps as a reminiscence for the German scientist Grotrian? In the newer diagrams the old written "z" is replaced with the usual "z".


  • robin_astro, Peter Z and rekokich like this

#2 Dadoo

Dadoo

    Lift Off

  • -----
  • Posts: 5
  • Joined: 24 Apr 2021

Posted 08 May 2021 - 06:47 AM

Thank you for posting the commented spectrum! I was trying Arcturus (K0III) for the first time this week. Didn't have much success, but I will try again, and it's nice to have a reference for what to expect. I was able to resolve Mg I and Na I in Aldebaran last year, and hoping to do at least the same with some other K-type stars.



#3 mwr

mwr

    Ranger 4

  • -----
  • topic starter
  • Posts: 308
  • Joined: 12 May 2018

Posted 08 May 2021 - 09:01 AM

I was trying Arcturus (K0III) for the first time this week. Didn't have much success, but I will try again, and it's nice to have a reference for what to expect.

Last year I was trying Arcturus as well with my non-modified Canon and Fujifilm cameras. See the thread here: https://www.cloudyni...ble-resolution/

 

When I was cleaning up my profile on Cloudy nights, I accidentally erased all images and spectra. They disappeared as well in all my posts so here they are again:

 

Folie1.JPG

 

Folie2.JPG

 

Folie3.JPG

 

As you said: It is always nice to have a reference and it is interesting to compare the results that were recorded with different setups. So I'm looking forward to seeing your spectra and thanks for your feedback!




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics