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Molecules in deep sky objects/interstellar space ?

PostPosted: Fri Oct 11, 2019 2:08 pm
by Robin Leadbeater
Molecules are detectable in cool stars, comets, gas planets by amateurs of course but the question came up in another forum as to whether amateurs are able to detect molecules in deep sky objects or the interstellar medium. Does anyone know of such measurements? Are there any molecular spectral signatures from these sources within the range of CCD/CMOS technology ?

Cheers
Robin

Re: Molecules in deep sky objects/interstellar space ?

PostPosted: Sat Oct 12, 2019 1:29 pm
by Andrew Smith
Not sure if this counts but you get absorption due to interstellar sodium in the spectra of some stars e.g. Rho Cas which I have captured.
Regards Andrew

Re: Molecules in deep sky objects/interstellar space ?

PostPosted: Sat Oct 12, 2019 2:32 pm
by Andrew Smith
Just scanned "Physics of the interstellar and intergalactic medium" which did not turn up anything obvious. The ones which might have been in the visible are also in our atmosphere and show as the teluric lines!

Maybe others know better

Regards Andrew

Re: Molecules in deep sky objects/interstellar space ?

PostPosted: Sat Oct 12, 2019 4:42 pm
by Robin Leadbeater
Hi Andrew,
Andrew Smith wrote:Not sure if this counts but you get absorption due to interstellar sodium in the spectra of some stars e.g. Rho Cas which I have captured.
Regards Andrew


I remember the IS lines from NA (and K) being really annoying when I was trying to measure these lines during Eps Aur eclipse. Not molecular though so no prize I am afraid :(

Re: Molecules in deep sky objects/interstellar space ?

PostPosted: Sat Oct 12, 2019 4:58 pm
by Robin Leadbeater
There is also an interesting comprehensive list of inter/circumstellar molecules on Wikipedia.
https://en.wikipedia.org/wiki/List_of_i ... _molecules
Though likely none detectable from the ground at visible wavelengths

Robin

Re: Molecules in deep sky objects/interstellar space ?

PostPosted: Sat Oct 12, 2019 9:47 pm
by Benjamin Mauclaire
Hi,

I confirm Robin's story about Na line from ISM. It's a pitty.
In my last paper about RR Lyr dynamics (https://ui.adsabs.harvard.edu/abs/2019A%26A...623A.109G, sec. 4), we first thought that Na line doubling came from Schwarzschild phenomenon (describing pulsation), but the reddish Na I line keep a steedy wavelength.
Although, the fact that Na reddish FWHM line was about 9 kms whicch is consistent with the ISM gas at high resolution.
We confirmed such hypothesis by looking for exsiting ISM bubble and loop between Earth and RR Lyr star in dedicated papers. Such reaserch domain is far from stellar astrophysics and is really an other world! Believe me, Univers is complex.

Benji

Re: Molecules in deep sky objects/interstellar space ?

PostPosted: Sun Oct 13, 2019 10:29 am
by Benjamin Mauclaire
Re.

Be careful that each line of sight has to be studied with dedicated bibliographic research.
Milky way is complex.

Benji