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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Changes in the supercycle lengths of some SU UMa-type dwarf novae have beendetected by other studies, and indicate that the mass transfer rates noticeablydecrease over time. We investigated the supercycle lengths of three SU UMa-typedwarf novae: AR Pic, QW Ser and V521 Peg, to determine if they have detectablechanges in their supercycles. We present the results of optical spectroscopicand photometric observations of these sources. Our observations were conductedin 2016 and 2017 at the Boyden Observatory and the Sutherland station of theSouth African Astronomical Observatory. The quiescent results indicated thatall three sources are typical SU UMa-type dwarf novae. We also present resultsof AR Pic and QW Ser in outburst and of V521 Peg during a precursor outburstand superoutburst. Light curves were supplemented by the Catalina Real-TimeTransient Survey, the ASAS-3 and ASAS-SN archives, and the AAVSO Internationaldatabase in order to investigate the long-term behavior of these sources. Ourresults combined with catalogued properties for all short-period dwarf novae,shows a possible relationship between the supercycle time in SU UMa systems andtheir orbital periods, which is interpreted as the decline in the mass transferrate as systems evolve toward and away from the 'period minimum'. At theshortest orbital periods, SU UMa systems are almost indistinguishable from WZSge systems. However, we propose that the scaleheight between the secondary'sphotosphere and L1 may be a factor that distinguish the SU UMa subclasses.

Transient behavior of three SU UMa-type dwarf novae; AR Pic, QW Ser and V521 Peg