SU Lyn Call for observations by Katarzyna Drozd

[James Foster]

Here is my Isis processed spectra of SU Lyn:

It looks virtually the same as Umberto's, since it was taken only 2 days later. I go out a tiny bit further in the IR, but other than that, the spectra is very
close to the ones I've seen here. The Fe & He line(s) identified in this chart are tentative of course; especially the FeI line around 6138A.

This would be a good object to after with an IR Lisa....I have the kit, but I still want to collect more visual data before I potentially "mess-up" on the IR kit install!

James

[Paolo Berardi]

Well done James! The red giant companion should be an M6 class star. The continuum is dominated by TiO (titanium monoxide) molecular bands. Two of these, for example, have band heads at 4955A and 5166A, close to where you located the Fe lines.

My observation for 29 and 30 march.

Lhires III and 1200 l/mm grating (R ~6000)



Lhires III and 2400 l/mm grating (R ~16000):



They shows how the highest resolving power allows you to see better the narrow and (relatively) faint emission component of h-alpha line (but some changes might have occurred).

Paolo

[Francois Teyssier]

James,

There are *no* emission lines visible at that resolution at the date. Only H alpha shows a weak emission in high res spectra.
The intensity of the the emission lines (Balmer, [OIII]) will increase with the (unkonwn at the date) orbital pahse

François

[Francisco Campos]

Amazing spectrum, Olivier. With that resolution and the echelle, I wonder if observations made with low resolution spectrographs have an interest...

Greetings
Fran

Hi Francisco,

Of course yes, low resolution spectrum is important for 3 reasons :
- You can do a spectrum with less exposure time than for an echelle spectrum (i have to use more than 3 hours to have a correct SNR...)
- You have a more accurate continuum with a low resolution spectrum because with echelle spectrum, to have the full spectrum, we have to merged all order.
- You can go deeper in the blue (with echelle, it's difficult to have a good SNR in the blue du to the magnitude of this star)

Hi, Olivier. Hi, François,

thank you very much for your comments. I'll carry on taking low resolution of SU Lyn. What about to choose a common reference star to get well corrected spectra? I'm currently using HIP 31665 = HD 46590 = 11 Lyn (A2 V). I think it's a good reference.

Talking about photometry, I could do it on the classical way (CCD and Johnson-Cousins filters) but I'm considering try to calibrate these spectra in flux and extract the BVR magnitudes. I'm not sure if the DADOS is able to do it well, since this spectrograph has only slits of 25, 35 and 50 um (there's not photometric slit, I'm afraid). I'm trying to reduce some spectra on this way of AG Dra but I'm having some problems to understand the method of two spectra that Buil explains on his webpage. At this moment, when I try to divide the flux calibrated spectra of the reference star with the raw one (multiplied by the inverse of the total exposure), I'm having a spectrum with a 0 signal

I have to try again...

Greetings
Fran

[James Foster]

To: Paolo,

RE:"The red giant companion should be an M6 class star."

I used M2 on my chart from the Sinbad catalog of SU Lyn when I was formatting the spectra fits for BeSS format; See:

I'm sure your right, but I don't really argue with the BeSS format as Sinbad shows it!

To: François

RE:"There are *no* emission lines visible at that resolution at the date. Only H alpha shows a weak emission in high res spectra."

Yes, that why I did not use the word "emission" but the word tentative; i.e. maybe maybe not. I'm pretty sure the O2 at 6869A is real (telluric) but as the others they could be Fe, Ti, etc......?
When the moon goes further east, I may try Ha on this object with my L-200's 1800 l/mm grating.....the LISA was easy to process for IS, but the Ha will be harder since I have only 3-5 lines to calibrate against.

James

p.s. Ill make my spectra charts smaller (800x600 looks better on these pages)!

[Robin Leadbeater]

Hi James,

SIMBAD is not a very reliable guide to spectral type. A better source is Brian Skiff's huge database of references
http://vizier.cfa.harvard.edu/viz-bin/V ... ource=B/mk
There you will see the M2 reference from 1956 and a more up to date reference M6III

Where does this dialogue box come from? I am not sure I understand the connection between spectral type and BeSS and how it might be used

Cheers
Robin

[Robin Leadbeater]

Note that the 6869A wavelength for the O2 Telluric band is not a single line but just the wavelength of the band head of a broad molecular band, made up of unresolved lines at this resolution. See here for example
http://www.astrosurf.com/buil/us/vatlas/vega3.gif
This will be blended with the stellar molecular bands though which are composed of hundreds of lines which are not fully resolved even at very high resolution . You should be able to see it more clearly in your hot reference star though.

Also as Paolo has pointed out the lines labelled Fe are actually molecular band heads, probably TiO

In general reliable line identification is very difficult at this resolution. You first need to know what is likely given the physical conditions in the star.

Cheers
Robin

[Francois Teyssier]

Dear James,

You'll find some explanation about the formation of the symbiotic spectrum in my ppt
(In french, but very few words, I'll try to translate it soon).


Powerpoint
http://www.astronomie-amateur.fr/Docume ... _2017.ppsx

pdf
http://www.astronomie-amateur.fr/Docume ... CE2016.pdf

And also the main lines observed in symbiotics

In Plot Spectra (T Lester) you have a list of the brightest common lines. A very nice tool.


Commented spectrum when the emission lines were bright (orbital variations)

All the best,

François

[Paolo Berardi]

Hi all! James, sorry for the late reply... Robin and François already answer you.

I had the opportunity to read a paper where it says that a M5.8III star is the best match (page 3):
SU Lyncis, a hard X-ray bright M giant: Clues point to a large hidden population of symbiotic stars
https://arxiv.org/abs/1604.08483

Also a comparison with Pickles spectra shows this really well. I used here the Fran's profile from ARAS database.



The only large continuum discrepancy I can see (I don't know what originates it) concerns the interval from about 6470A to 6600A. You can see here at mid resolution (R ~6000) but it is quite visible also in low-res profiles. HD18191 is a M6III star.



Paolo

[umberto sollecchia]

Salut, placez un nouveau profil spectral et une comparaison avec le jour 30/03/2017 et le jour 07-04-2017.Umberto

Profilo sulyn.png (9 KiB) Viewed 10381 times

Comparison.png (11.23 KiB) Viewed 10381 times