New dwarf nova in Cygnus – observations requested

[Jeremy Shears]

Chris Lloyd and Maxim Usatov report a likely new dwarf nova of the SU UMa class in an Astronomer’s Telegram just published online: https://www.astronomerstelegram.org/?read=16676

Max used his remote Alnitak telescope located in Spain for follow up observations.

Further observations of this outburst are urgently encouraged, especially time resolved photometry.

[Stewart John Bean]

Got Slooh Canary 2 booked for this evening.

[Stewart John Bean]

I get 16.74 CV at
2024/06/29 04:14:01
Slooh Canary 2

[Gary Poyner]

I measured it at the same magnitude 16.738C one minute after you Stewart (mine was the next job after you in the queue).

Gary

[Magnus Larsson]

Hi!

I managed to take a short time series last night, unfortunately interrupted by clouds. Uploaded the observations with the name TCP J20023703+3947002, which is what VSX gives for this object.

The observations shows the beginning of something that *could* be a superhump. But far from sure. I’ll return to it the next few nights.

Attached is a screenshot of the lightcurve from Peranso.

Magnus

Attachments:

1. 

   AT2024lwu.png
   

[Jeremy Shears]

Thanks Magnus. Interesting.

[Mr Ian David Sharp]

Hi all,

I took a series of 17 exposures early this morning from my C11 in Spain over an hour. It varied at between 16.7 and 16.8 in the V band. See attached.

I’ve also attached a screen shot with the field in AstroArt with the 5 ref and one check star I used. All the comp stars came from the AAVSO chart X36870MV.

WE have 2 entries in the BAA photometry database – one for TCP J20023703+3947002 and one for AT 2024lwu and I’ve uploaded my results to both. As Magnus mentions above, the AAVSO use TCP J20023703+3947002 in VSX.

Cheers
Ian.

Attachments:

1. 

   Screenshot-2024-07-02-081243.jpg
   

[Mr Ian David Sharp]

Mr Ian David Sharp wrote:

I took a series of 17 exposures early this morning from my C11 in Spain over an hour. It varied at between 16.7 and 16.8 in the V band. See attached.

Sorry, here’s the graph which I neglected to attach!

Attachments:

1. 

   20240702_TCP-J200237033947002_V_PixelSkies-C11_IDS_plot_lines.png
   

[Jeremy Shears]

Great stuff, Ian. Thank you.

[Mr Ian David Sharp]

I took a longer run last night, about 2h 20m, and used 300s exposures in a V filter to beef up my S/N to about 60 (I was taking 180s).

A bit of variability over 0.2 mags, but no pattern to it as far as I can see. Average V mag. is 16.8.

Cheers
Ian.

Attachments:

1. 

   20240703_TCP-J200237033947002_V_PixelSkies-C11_IDS_plot_points.png
   

[Magnus Larsson]

Hi!

So I managed to capture some 180 60 sec exposures with a clear filter on our CDK17 in southern Spain. The series shows bumps that looks lite superhumps to me, see the attached screenshot from Peranso. The measured period is 0.072982 days or 1.751 hours. THe amplitude is about 0.165 mag.

Magnus

Attachments:

1. 

   AT2024lwu_20240702.png
   

[Jeremy Shears]

Certainly looks like superhumps.

[Mr Ian David Sharp]

Here are my results from last night. Moved to an L filter, 120s. I tried some period fits, but wasn’t convinced!

Cheers
Ian.

Attachments:

1. 

   tycho.jpg
   

[Maxim Usatov]

Just uploaded 35 observations to the database. Thanks to Chris Lloyd for helping me with the V mag field catalog derived from Gaia magnitudes, as APASS DR9 wasn’t faint enough.

Max

JulianDate Filter VarAbsMag VarAbsErr ExpLen CmpStar
2460488.44175 V 16.49 0.09 300.0 Ensemble
2460488.44562 V 16.47 0.09 300.0 Ensemble
2460488.44939 V 16.48 0.09 300.0 Ensemble
2460488.45318 V 16.5 0.09 300.0 Ensemble
2460488.45696 V 16.51 0.09 300.0 Ensemble
2460488.46074 V 16.48 0.1 300.0 Ensemble
2460488.46452 V 16.41 0.1 300.0 Ensemble
2460489.4109 V 16.56 0.13 300.0 Ensemble
2460491.4104 V 16.75 0.1 300.0 Ensemble
2460491.41421 V 16.75 0.1 300.0 Ensemble
2460491.41797 V 16.66 0.1 300.0 Ensemble
2460491.42173 V 16.66 0.09 300.0 Ensemble
2460491.42549 V 16.63 0.09 300.0 Ensemble
2460491.4293 V 16.65 0.1 300.0 Ensemble
2460491.4331 V 16.67 0.1 300.0 Ensemble
2460491.43684 V 16.69 0.1 300.0 Ensemble
2460491.44063 V 16.72 0.09 300.0 Ensemble
2460491.44442 V 16.67 0.09 300.0 Ensemble
2460491.44817 V 16.72 0.08 300.0 Ensemble
2460493.46185 V 16.79 0.09 300.0 Ensemble
2460493.46559 V 16.81 0.09 300.0 Ensemble
2460493.46931 V 16.82 0.1 300.0 Ensemble
2460493.47304 V 16.81 0.11 300.0 Ensemble
2460493.47675 V 16.83 0.1 300.0 Ensemble
2460493.48059 V 16.82 0.1 300.0 Ensemble
2460493.4843 V 16.84 0.1 300.0 Ensemble
2460493.48802 V 16.83 0.1 300.0 Ensemble
2460493.49172 V 16.89 0.1 300.0 Ensemble
2460493.4955 V 16.84 0.1 300.0 Ensemble
2460494.48389 V 16.89 0.1 300.0 Ensemble
2460494.48765 V 16.89 0.1 300.0 Ensemble
2460494.49144 V 16.87 0.1 300.0 Ensemble
2460494.49521 V 16.87 0.1 300.0 Ensemble
2460495.40058 V 16.92 0.1 300.0 Ensemble
2460495.49383 V 16.92 0.08 300.0 Ensemble

Attachments:

1. 

   Screenshot_2024-07-04_16-37-17.png
   

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