[vsnet-alert 24261] Re: [vsnet-outburst 25110] Re: (cba:chat) ASASSN-20eo: peculiar object

Thu May 7 07:50:54 JST 2020

Hi Josch, all,

Thanks for informing. Your comment is correct: I observed ASASSN-20eo extensively last night, when it already declined from mag 15.5 (CV) to mag 16.3 over a timespan of 4.9 hrs. It continued to show irregular short-term ~0.3 mag fluctuations. I observed it also tonight, but still need to process my observations.

Best regards
Tonny

-----Original Message-----
From: vsnet-outburst [mailto:vsnet-outburst-bounces at ooruri.kusastro.kyoto-u.ac.jp] On Behalf Of hambsch at telenet.be
Sent: woensdag 6 mei 2020 23:32
To: cba-chat at cbastro.org
Cc: vsnet-campaign-dn at ooruri.kusastro.kyoto-u.ac.jp; 'vsnet-outburst'; vsnet-newvar at yahoogroups.com; 'ALERT, VSNET'; 'Taichi Kato'
Subject: [vsnet-outburst 25110] Re: (cba:chat) ASASSN-20eo: peculiar object

Hi, 
I have tried tonight from my backyard in Belgium to observe this transient. Near full moon was of course no help but I measured around mag. 18. Hence the outburst seemed to be over. 
Regards Josch 
----- Oorspronkelijk bericht -----
Van: Tonny Vanmunster <tonny.vanmunster at gmail.com>
Aan: cba-chat at cbastro.org, 'Taichi Kato' <tkato at kusastro.kyoto-u.ac.jp>, 'ALERT, VSNET' <vsnet-alert at ooruri.kusastro.kyoto-u.ac.jp>, vsnet-campaign-dn at ooruri.kusastro.kyoto-u.ac.jp, vsnet-newvar at yahoogroups.com, 'vsnet-outburst' <vsnet-outburst at ooruri.kusastro.kyoto-u.ac.jp>
Verzonden: Tue, 05 May 2020 12:31:51 +0200 (CEST)
Onderwerp: (cba:chat) ASASSN-20eo: peculiar object

Dear colleagues

I managed to obtain 5.4 hours of unfiltered CCD photometry last night (2020, May 04/05) of ASASSN-20eo at my CBA Belgium Observatory using a 0.40-m f/10.0 telescope with STT-3200ME CCD camera. Sky conditions were moderate with some clouds towards the second half of the session.

The resulting light curve (see below) shows some very interesting behaviour, quite a-typical from classical dwarf novae. The object shows large fluctuations (up to 0.3 mag) on time scales of 10-15 minutes, superimposed over an overall gradual decline of about 0.6 mag, which stabilized towards the end of my

observing session.

All fluctuations are highly irregular, with no obvious periodicity.

This object definitely merits further intensive photometric and spectroscopic coverage!

I will send my observations to the AAVSO, CBA and VSNET for further processing.

Best regards

Tonny

--

Tonny Vanmunster

CBA Belgium Observatory

CBA Extremadura Observatory

 <http://www.cbabelgium.com> www.cbabelgium.com

 <http://www.peranso.com> www.peranso.com

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