[vsnet-alert 22497] ASASSN-18rg can be an AM CVn star

[Keisuke Isogai]

ASASSN-18rg can be an AM CVn star

     The short orbital period of 0.032 d = 46 min and the "double superoutbursts"phenomenon
suggest that this object is the best candidate of the helium-rich CV, namely AM CVn star.

Further observations and spectroscopy are strongly encouraged!

On 2018/09/07 21:23, Tonny Vanmunster tonny.vanmunster at gmail.com via vsnet-alert wrote:
> Dear colleagues,
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> I have just concluded the analysis of my 2018, Sep 06/07 unfiltered CCD photometry session of ASASSN-18rg. Observations were made at CBA Extremadura Observatory (Spain),  using a 0.40-m f/5.1 telescope and SX-46 CCD camera, under very clear skies.
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> The resulting light curve clearly reveals the presence of “superhumps” with an amplitude of 0.10 mag, hence classifying this object as a new SU UMa type dwarf nova. A preliminary period analysis using the ANOVA, Lomb-Scargle and PDM methods (Peranso), yields a combined superhump period of 0.0340 +/- 0.0008d.  This is a very short period system, so I leave it up to the professional astronomers to comment on possible different interpretations of this periodic signal. E.g., this might be growing ‘stage A superhumps’, as commented by Kojiguchi Naoto (VSNET Kyoto Univ team) in vsnet-outburst 22607. The object was at mag 13.9 (CV) on Sep 07th.  I will publish above lightcurve on the “Cataclysmic Variables” Facebook page.
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> Observations will be sent to AAVSO, CBA and VSNET for further analysis.
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> Follow-up observations are highly recommended to further refine the superhump period.
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> Best regards
> Tonny
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> Tonny Vanmunster
> CBA Belgium Observatory
> CBA Extremadura Observatory
>   <http://www.cbabelgium.com> www.cbabelgium.com
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>   <http://www.peranso.com> www.peranso.com
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