American Association of Variable Star Observers (AAVSO)
Sat, 03/19/2022 - 19:51

AAVSO Alert Notice 773 announces a long-term campaign on the YSO EX Lup. Please see the notice for details and observing instructions.

There are threads for this campaign under the following forums:

- Campaigns and Observation Reports:
- Young Stellar Objects (YSO):

Please subscribe to these threads if you are participating in the campaign so you can be updated. Join in the discussion or ask questions there!

Many thanks, and Good observing,

Elizabeth O. Waagen, AAVSO HQ

American Association of Variable Star Observers (AAVSO)

Hi all

Good coverage has been maintained since the outburst in March.  It's clear to see the reported 7.41 day radial velocity period in the data.  A rough VStar analysis shows a 7.37 day period in V since the outburst.  It's also evident in I, R and B bands as well.



American Association of Variable Star Observers (AAVSO)
EX Lup Campaign

Hi Andrew (and everybody),

First off, thanks for all of your contributions to this campaign! Andrew is completely correct -- the coverage since March looks really nice. The system is almost -- but not quite -- back down to the pre-outburst level, so continued effort for at least another month or so would be extremely valuable.

Also, thanks, Andrew, for highlighting what looks to be the orbital periodicity in the data -- that's not something I had necessarily expected to see, but it's a really nice bonus!

For me, the thing I'm most excited about is the nice multi-colour coverage, since the coupled colour-magnitude evolution is what I'm primarily interested in. Specifically, I am hoping to see if we can detect hysteresis in color-magnitude diagram -- i.e. whether the system evolves differently up to the outburst than down. I've tried to take a first look at this already, but it'll require a more careful analysis to know if there is hysteresis. Getting all the way back down to quiescence will also be hugely helpful in this analysis.

Anyway, thank you all so much for you help with this campaign!





Vereniging Voor Sterrenkunde, Werkgroep Veranderlijke Sterren (Belgium) (VVS)
EX Lup in H-alpha

Hi Christian,

I also have H-alpha observations, which I have not yet submitted to the AAVSO database.

I could make all my images available to you if you are interested.



Astronomia Sigma Octante - Centro de Investigacion y Estudio en Astronomia (Bolivia) (ASO)
EX Lup Campaign results

Hello Dr. Christian

Me and a couple of friends have contributed to the best of our possibilities to this campaing and we are wondering if you have published or will publish any paper about the star Ex Lup. It would be great to have access to that paper (if any) so we can see the fruits of our efforts.

Thank you beforehand for your kind response.

Best Regards