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

We carried out the photometric observations of the SU UMa-type dwarf nova ERUMa during 2011 and 2012, which showed the existence of persistent negativesuperhumps even during the superoutburst. We performed two-dimensional periodanalysis of its light curves by using a method called "least absolute shrinkageand selection operator" (Lasso) and "phase dispersion minimization" (PDM)analysis, and we found that the period of negative superhumps systematicallychanged between a superoutburst and the next superoutburst. The trend of theperiod change can beinterpreted as reflecting the change of the disk radius.This change of the disk radius is in good agreement with the predicted changeof the disk radius by the thermal-tidal instability (TTI) model. The normaloutbursts within a supercycle showed a general trend that the rising rate tomaximum becomes slower as the next superoutburst approaches. The change can beinterpreted as the consequence of the increased gas-stream flow onto the innerregion of the disk as the result of the tilted disk. Some of the superoutburstswere found to be triggered by a precursor normal outburst when the positivesuperhumps appeared to develop. The positive and negative superhumps co-existedduring the superoutburst. The positive superhumps were prominent only duringfour or five days after the supermaximum, while the signal of the negativesuperhumps became strong after the middle phase of the superoutburst plateau. Asimple combination of the positive and negative superhumps was found to beinsufficient in reproducing the complex profile variation. We were able todetect the developing phase of positive superhumps (stage A superhumps) for thefirst time in ER UMa-type dwarf novae. Using the period of stage A superhumps,we obtained a mass ratio of 0.100(15), which indicates that ER UMa is on theordinary evolutional track of CVs.

Study of Negative and Positive Superhumps in ER Ursae Majoris