English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present the first ever discovery of a short-period and unusuallyhelium-deficient dwarf nova KSP-OT-201701a by the Korea Microlensing TelescopeNetwork Supernova Program. The source shows three superoutbursts, each led by aprecursor outburst, and several normal outbursts in BVI during the span of ~2.6years with supercycle and normal cycle lengths of about 360 and 76 days,respectively. Spectroscopic observations near the end of a superoutburst revealthe presence of strong double-peaked HI emission lines together with weak HeIemission lines. The helium-to-hydrogen intensity ratios measured byHeI{\lambda}5876 and H{\alpha} lines are 0.10 {\pm} 0.01 at a quiescent phaseand 0.26 {\pm} 0.04 at an outburst phase, similar to the ratios found inlong-period dwarf novae while significantly lower than those in heliumcataclysmic variables (He CVs). Its orbital period of 51.91 {\pm} 2.50 minutes,which is estimated based on time series spectroscopy, is a bit shorter than thesuperhump period of 56.52 {\pm} 0.19 minutes, as expected from thegravitational interaction between the eccentric disk and the secondary star. Wemeasure its mass ratio to be 0.37^{+0.32}_{-0.21} using the superhump periodexcess of 0.089 {\pm} 0.053. The short orbital period, which is under theperiod minimum, the unusual helium deficiency, and the large mass ratio suggestthat KSP-OT-201701a is a transition object evolving to a He CV from along-period dwarf nova with an evolved secondary star.

Discovery of a Short-Period and Unusually Helium-Deficient Dwarf Nova KSP-OT-201701a by the KMTNet Supernova Program