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Followup on SS Cyg: Alert Notice 536 / Special Notice #412

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Followup on SS Cyg: Alert Notice 536 / Special Notice #412

Fellow AAVSO members, I am one of the international collaborators mentioned in Alert Notice 536 and we wanted to make a request for rapid submission of any data on SS Cyg tonight (night of February 10 - 11). SS Cyg may be going into outburst, but there is a potential that this source is undergoing a hiccup like that seen two outbursts ago. To help our collaboration most accurately trigger multiwavelength observations, it is critical for us to determine if SS Cyg is in fact going into outburst. Since SS Cyg is currently transiting in the day, your best bet for observing this source from many locations in the Northen Hemisphere may be in or soon after twilight conditions, both at the evening and in the morning. Even observations at high airmass may be helpful. As the Alert says,

"Please use WebObs to report your observations of SS Cyg to the AAVSO as soon after you make them as possible.
If you see it [at] 11.5 V or brighter, please report [your observations] immediately."

cpmalo87's picture
m ~ 11


   My visual estimate at 0116 was 11.1.  Previous observations from a few hours ago are pretty close (see webobs).  If it is going into outburst, it seems to be rising rather slowly.  Confirming observations are needed.  I'll try to get another estimate around 1200 UT if I wake up in time...


Re: m ~ 11

Thanks for the update! I agree that the behaviour seems more consistent with the hiccup than a typical rise:


Typical Rise:

Deconinck Michel
Deconinck Michel's picture
Obs from south France

Hi, this is a very interesting star!  From 4:oo to 5:15 UTC my visual estimations goes from 11.5 to 10.7. my SQM gives 20.21.  I posted my estimations via WebObs.  Hope this helps.

Could we receive some scientifical info after the multiwave observation ? that would be so kind.


stellakafka's picture
some info

Dear Michael,

Thank you for your contribution - all data points are important! 

We will ask for the PIs to provide information on their campaign results when they are ready. The goals of their campaign are posted in our alert:

To give you the "big picture": jets were known to exist in all accreting disk sources (black holes, neutron stars, protostars) but not on accreting white dwarfs (CVs), to the point where people were "adjusting" their theories on jet formation to explain the lack of such phenomena in CVs. Only very recently (2008), and with the help of the AAVSO, SS Cyg was discovered to have jets during its outburst phase. The results were published in Science (a copy of the paper can be found here: and made a huge impact in the field. We now have a complete picture, that _all_ accreting sources have jets, which in turn is opening a new field of studies for astronomers. More observations are needed in order to understand the jet ejection mechanism, opening angle and conditions under which jects are formed/ejected/collimated(?) in accreting white dwarfs. It is natural to start by trying to understand SS Cyg, which is the first source for which jets have been reported to be present. For this research, ground-based light curves are critical: preliminary results show that the onset of the jet is happening at the beginning of the outburst (hinting on the jet ejection mechanism) and evolves during the outburst, tracing the optical light curve. Therefore, every data point acquired during this campaign is critical for our understanding of this phenomenon. 

I hope this helps. I am really looking forward to the scientific outcome of this campaign. This is where the AAVSO observers help make breakthroughs in science!

Best wishes - clear skies,




Deconinck Michel
Deconinck Michel's picture
Hello Stella Thank you so

Hello Stella

Thank you so much for this information, I really appreciate.  That helps me to push some amateur astronomers of my area to try this kind of so passionate observation.

Kind regards, Michel

Tony Vale
SS Cyg

    I made visual observations of SS Cyg last night about 11 hours apart ( at 10.79722 and again at 11.23958) and it certainly appreared to have faded very slightly over that time. 

giufrust's picture
Just sent to webobs my

Just sent to webobs my measure: V'= 10.72 +-0.09 mag at airmass 1.7 yesterday evening at 16.55 utc. 

Will try again this evening, weather permitting.


G. Frustaci

LMA's picture
SS Cyg is ON

I am on SS Cyg, it is around V mag 8.7.  Will be back with more precise data in about one hour.

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