Z CMa in outburst

Information about outbursts of eruptive stars, Be activity, ...
Francois Teyssier
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Joined: Fri Sep 23, 2011 1:01 pm
Location: Rouen
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Re: Z CMa in outburst

Post by Francois Teyssier »

Thank you for the alert, Fran
Very nice spectra at low and high resolution. Congratulations
I'll add a page in the next letter. Fran, could you send me the fit, please?
All the best,

François
Joan Guarro Flo
Posts: 611
Joined: Thu Nov 03, 2011 8:50 pm

Re: Z CMa in outburst

Post by Joan Guarro Flo »

Hi,

This is a comparison of two nights the star Z CMa, in the H-alpha and the Sodium region.

Cheers, Joan.
Attachments
Comparacio-1 zcma.png
Comparacio-1 zcma.png (6.63 KiB) Viewed 8248 times
Comparacio-2 zcma.png
Comparacio-2 zcma.png (9.56 KiB) Viewed 8248 times
Paolo Berardi
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Joined: Thu Sep 29, 2011 10:51 pm

Re: Z CMa in outburst

Post by Paolo Berardi »

Hi all,

thank you for reporting the outburst alert and sharing your excellent spectra. I also was able to observe Z CMa on 3 March.

I used the 1200 l/mm grating to capture the h-beta and Fe II multiplets region. Very strong p-cygni profile absorption for h-beta (almost saturated on my frames).

Image

After, I changed to 2400 l/mm to observe the He I and Na I D doublet region. The interesting comparison by Joan reveals fast changes of both lines. We should try to observe it often.

Image

The He I 5875.97A line absorption is strong and the sodium doublet shows an emission component.
I made the heliocentric radial velocity plot for the Na D1 line at 5889.95A. Various absorption components are visible in the profile at rv -110 (minimum), -240 and -318 Km/s. The absorption has a terminal velocity of ~ -500 Km/s. The positive value +26 Km/s should be the heliocentric radial velocity of the interstellar cloud.

Image

I hope to observe the stellar system again. Very bad weather here, though.

Clear sky!
Paolo
Forrest Sims
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Joined: Thu Feb 09, 2017 5:52 pm

Re: Z CMa in outburst

Post by Forrest Sims »

I saw this post and thought it a good idea to try my hand at collecting data on Z CMa. I used a LISA with the calibration module on a Celestron 8” with f6.3 focal reducer and an Atik414ex camera. ISIS was used to process the data. This spectrum was made with 7 300sec images of the target spectrum. Instrument response was determined with 9 300sec images of HD072660. (This reference star was not as close as I had hoped to the target but it was all I could find. Later I learned from this forum about the wonderful MILES Search Excel tool by Paolo Berardi for choosing a reference star near the target star.) Also by the time I found the target star and had a space between the clouds, Z CMA was down to an altitude of 20 deg, not good. Here is the result and my first attempt at posting a result beyond the Introduction segment of this forum.

Cheers!
Forrest
Z CMA.png
Z CMA.png (31.61 KiB) Viewed 8180 times
Francois Teyssier
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Re: Z CMa in outburst

Post by Francois Teyssier »

Nice result, Forrest !
The LISA is well tuned; I think that the real resolution of the Spectrum is about 1000.
The only issue could be the atmospheric correction, and a significative difference with Fran's spectrum
All the best,
François

PS you can send me the fit file, for including in the next letter
Forrest Sims
Posts: 86
Joined: Thu Feb 09, 2017 5:52 pm

Re: Z CMa in outburst

Post by Forrest Sims »

Thank you François for your very kind comments!

First a correction to my post: The 7 exposures of the target star Z CMa were actually 180 sec not 300 sec as stated in the plot title.

Regarding the Spectrum resolution with the LISA.
I have calculating FWHM values for some of my ArNe lamp lines. Interesting and wildly variable.

For instance, for the well known Ne line at 5944.834Å, I get FWHM of between (1.915, 1.96, 1.963, 1.904, 1.911 pixels) using the Line PSF function. The difference in values is due to experimenting with the placement of the vertical rectangle about the line. I generally tried to stay within the spectrum binning horizontal lines. Using 2.594 Å/pixel for my camera, I get me R values between 1,167 and 1,204. Which is kind of in the ballpark for a nominal R=1000 device. I think have identified the Ne line at 7,438.90Å and here I get a range of FWHM of (2.846, 4.175, 3.401, 3.845, 4.172) again repeating the process of selecting a vertical oriented rectangle and recording the FWHM value. For this Ne line I get R values of 687 to 1,008.

At the Blue end of the spectrum Ar line 4,735.91 and a range of FWHM values (3.100, 3,970, 3.210, 4.099, 3.794) with a range of R values of 445 to 589. I am not certain that I identified the correct line for Ar but even so the resolution dropped off significantly toward the blue end of the spectrum. Although I have been told that the blue end of the LISA spectrum falls off to a lower value due to its optical design. ISIS obviously has its own secret algorithm to calculate resolution. Do you have any suggestion on how to calculate the resolution?

Do you think the atmospheric correction you speak of due to to the low altitude of the target at acquisition time or to my use of a Miles reference star with too different an airmass value and or not such good processing technique?

I tried this target again last night but have not begun to process the spectrum data.

I have sent you the fits file for this graph.

All the best,
Forrest
Paolo Berardi
Posts: 578
Joined: Thu Sep 29, 2011 10:51 pm

Re: Z CMa in outburst

Post by Paolo Berardi »

Hi Forrest, thank you for sharing your observation and congratulations for the new spectrograph! Here you can find many experts that can help you to push it to the limit. Excellent choice to use ISIS for processing your data.

My new observations for 8, 9, 13 and 14 march.

A quick change in 1 day of He I 5875.97A p-cygni absorption (delta Vr is about 140 Km/s) while the sodium doublet is stable.

Image

The spectrum after the rebrightening (13 march).

Image

Observations grouped, helium and sodium lines (heliocentric corrected).

Image

The last observation, with Lhires III and 600 l/mm grating, concerns the near-IR region. I used a Wratten #25 filter to avoid the 2nd order contamination. The profile is dominated by the NIR Ca II triplet (8498, 8542 and 8662A) but shows other lines, almost all with P-Cygni profile. Maybe O I 8446 (not strong), Mg I 8807 and some hydrogen Paschen lines.

Image

Paolo
Joan Guarro Flo
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Joined: Thu Nov 03, 2011 8:50 pm

Re: Z CMa in outburst

Post by Joan Guarro Flo »

Buon lavoro, Paolo.

Joan.
Tim Lester
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Joined: Fri Apr 04, 2014 6:31 pm
Location: Arnprior Ontario

Re: Z CMa in outburst

Post by Tim Lester »

My results for regions around H alpha and H beta, acquired March 18 and 19.
zcma_ 20170318_003_tlester.png
zcma_ 20170318_003_tlester.png (45.83 KiB) Viewed 8073 times
zcma_ 20170319_017_tlester.png
zcma_ 20170319_017_tlester.png (19.63 KiB) Viewed 8073 times
Tim
Francois Teyssier
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Re: Z CMa in outburst

Post by Francois Teyssier »

Dear All,
Your very nice spectra are in the base
http://www.astrosurf.com/aras/Aras_Data ... e/ZCMa.htm

Also updated : http://www.astrosurf.com/aras/Aras_Data ... 0+0605.htm

Please Check

All the best,

François
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