C2014Q2

Show your spectra, your results ...
Joan Guarro Flo
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Joined: Thu Nov 03, 2011 8:50 pm

Re: C2014Q2

Post by Joan Guarro Flo »

Paolo Berardi wrote:Hi Joan, François and all,

yes, we should observe it... but weather must agree! ;)

François, thank you for documents about comets. I see your topic just now, when I wrote my post. Asap I'll read them with interest. I hope to find other information about spectral lines.

Yesterday I observed the comet with Lhires III 1200. The R~5000 profile includes wavelengths from 5285 to 5765A. I'd like to arrange a larger interval with several observations (weather permitting).

In the same observing session I took separate spectra for sky background and solar light (the Moon spectrum), then a reference star for general response.

False nucleus region and close coma (reflectance spectrum):

Image

I put some labels for strongest lines (I hope they are ok). It is not easy for me to identify faint lines due to the density of the emissions in some of bands. Also difficult to understand which emission lines are the continuation of these bands. I could not identify three lines at about 5318A, 5333A and 5646A. If you can find something about, please let me know. In a 2005 paper (Frozen Hydrocarbon Particles of Cometary Halos as Carriers of Unidentified Emissions, Irakli Simonia) I found a 5318A wavelength coincidence with a Chrysene molecule C18H12 but I don't know if it is effectively in relation.

Some intermediate steps during data reduction:

Observed spectrum:

Image

Sky background spectrum:

Image

Observed - sky background:

Image

Moon spectrum:

Image

Reflectance spectrum (observed sky removed / Moon):

Image

Paolo
Ciao Paolo:

Congratulations !!

As expected of you, a very good job !! Do you know how to make the very LHIRES-III.

Due to the inversion, there is a persistent fog in the valley of the Ebro river, also affects Sta. Maria M.
For three nights I can not observe and fog persists ...

Saluti tanti, Joan.


Jo sóc en Charlie.
Massimiliano M
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Re: C2014Q2

Post by Massimiliano M »

Hello to everybody.
This is our small contribution.
Done with Lhiress III and 150l/mm grid.
Full moon and some clouds didn't help us. :|

"Je suis Charlies"

Massimiliano Mannucci
Nico Montigiani
Lapo Ferrini
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Massimiliano Mannucci
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Francois Teyssier
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Re: C2014Q2

Post by Francois Teyssier »

Data base updated with spectra from Terry Bohlsen, David Boyd, Paolo Berardi and Jacques Montier

François
Jacques Montier
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Re: C2014Q2

Post by Jacques Montier »

Thanks François,
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Jacques Montier
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Christian Buil
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Re: C2014Q2

Post by Christian Buil »

Here a high resolution spectrum of C2014 Q2 taken at R = 11000 with eShel spectrograph on C11 telescope (16 x 600 sec. exposure). Nucleus region (observed version):

Image

After solar spectrum subtraction (moon light) -> gaseous emission component:

Image

Detail of a C2 band (compare with Paolo spectrum):

Image

and a detail:

Image
(the atmospheric OI 5577.3 A line is only partially removed in this document)

The 5160 A C2 band:

Image

Now a "ultra high resolution" of [OI] 6300.3 A line (+some NH2) taken with VHIRES spectrograph at R = 50000 (9x600 sec. exposure) - compared to eShel spectrum ar R = 11000 (blue plot):

Image

The 6300 A line is quasi-monochromatic.

Christian
Paolo Berardi
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Re: C2014Q2

Post by Paolo Berardi »

Many thanks to all!

Christian, those are really impressive results! eShel spectrograph is a very poweful instrument. A lot of work to give a name to all transitions! It is instructive to see the effect of different resolution on the very narrow [OI] 6300 line whose top appears lower than the 5160 A headband in low-res spectra.

Perhaps an old question... subtracting or dividing for solar spectrum? Subtracting doesn't rescale the emission components. It is preferable for this reason?

Paolo
Joan Guarro Flo
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Re: C2014Q2

Post by Joan Guarro Flo »

Christian, the spectrum is very good !!

Congratulations !! Joan.
Christian Buil
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Re: C2014Q2

Post by Christian Buil »

Paolo,

The question about sun dust reflectance spectrum removal is not so simple.

For these present spectra I have subtracted the Sun (Moon in fact) spectrum.

The optical fiber of eShel is centered on the nucleus during my observation, so the apparent spectrum contain two components :

(comet dust spectrum + comet gaz spectrum)

I have scaled (by choosing with some trial the K-value i.e. by hand) my Moon spectrum for erase Fraunhofer lines (Na, Ha, Mg,...). The operation is:

comet gaz spectrum = (comet dust spectrum + comet gaz spectrum) - K x (moon spectrum)

Christian
Joan Guarro Flo
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Re: C2014Q2

Post by Joan Guarro Flo »

A respite from fog in Sta. Maria let me observed again the C / 2014 Q2.

J.Guarro
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Paolo Berardi
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Re: C2014Q2

Post by Paolo Berardi »

Thanks for information Christian. I'd try on my spectrum.

Dear Joan, finally the fog has left Sta. Maria... As usual, very nice spectrum!

Ciao!
Paolo
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