[vsnet-alert 24109] ASASSN-20ds and MASTER OT J061642.05+435617.9: new SU UMa-type dwarf novae

[Tonny Vanmunster tonny.vanmunster@gmail.com via vsnet-alert]

Dear colleagues,

 

I have collected multiple nights of unfiltered CCD observations of both ASASSN-20ds and MASTER OT J061642.05+435617.9, using my CBA Belgium Observatory telescope. Last night’s observations (2020, Mar 27/28) finally show well developed superhumps in both systems, hence establishing them as new SU UMa-type dwarf novae. Looking at the superhumps, I have no indications (so far) that these might be WZ-Sge type dwarf novae. 

 

ASASSN-20ds: using 4 different period analysis methods [Lomb-Scargle, Generalize Lomb-Scargle, PDM, ANOVA] (Peranso 3.0), the combined superhump period is 0.0553 +/- 0.0006d, amplitude of 0.17 mag. ASASSN-20ds was at mag 16.1 (CV ) on Mar 27th.

 

MASTER OT J061642.05+435617.9: using 4 different period analysis methods [Lomb-Scargle, Generalize Lomb-Scargle, PDM, ANOVA] (Peranso 3.0), the combined superhump period is 0.0574 +/- 0.0014d, amplitude of 0.18 mag. The object was at mag 16.6 (CV) on Mar 27th.

 

Observations will be sent to AAVSO, CBA and VSNET for further analysis.

Follow-up observations are highly recommended to refine the superhump period and to study its further evolution.

 

Best regards

Tonny


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Tonny Vanmunster
CBA Belgium Observatory
CBA Extremadura Observatory
 <http://www.cbabelgium.com> www.cbabelgium.com
 <http://www.peranso.com> www.peranso.com