[vsnet-outburst 22277] ASASSN-18nn: new SU UMa type dwarf nova

Tue Jun 19 17:15:53 JST 2018

Dear colleagues,

I have just concluded the analysis of my 2018, Jun 18/19 unfiltered CCD
photometry session of ASASSN-18nn. Observations were made at CBA
Extremadura Observatory,  using a 0.40-m f/5.1 telescope and SX-46 CCD
camera, under a very clear sky.

The resulting light curve unambiguously shows the presence of superhumps
with an amplitude of 0.13 mag. A period analysis using the ANOVA,
Lomb-Scargle and PDM methods (Peranso), yields a combined superhump period
of 0.0574 +/- 0.0005d, hence establishing this object as a new SU UMa type
dwarf nova. The object was at mag 15.2 (unfiltered) on Jun 18th.

Astrometry yields following position (J2000.0, UCAC4 based): RA = 21h 10m
49.12s, Dec = +25d 15’ 50.8” with uncertainty of 0.2” in RA and Dec.

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

Best regards
Tonny

Tonny Vanmunster
CBA Belgium Observatory
CBA Extremadura Observatory
www.cbabelgium.com
www.peranso.com
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