CCD photometry of the first observed superoutburst of KP Cassiopeiae in 2008 October

TL;DR

This study presents detailed CCD photometry of the first observed superoutburst of KP Cassiopeiae in 2008, revealing superhump period evolution, orbital period, and outburst characteristics of this SU UMa-type dwarf nova.

Contribution

It provides the first detailed photometric analysis of KP Cassiopeiae's superoutburst, including superhump period change, orbital period estimation, and outburst duration and amplitude.

Findings

Superhump period shortened at cycle 15

Orbital period estimated at 0.0814 days

Superoutburst lasted 8-12 days with 5 magnitude amplitude

Abstract

We report CCD photometry and analysis of the first observed superoutburst of the SU UMa-type dwarf nova KP Cassiopeiae during 2008 October. We observed a distinct shortening of the superhump period at superhump cycle 15. Before that point Psh was 0.08556(3) d and afterwards it evolved from 0.08517(2) d to 0.08544(3) d with a rate of period change dPsh/dt = 3.2(2) * 10-5. We measured the likely orbital period as 0.0814(4) d placing KP Cas just below the period gap. The superhump period excess is 0.048(5) and, empirically, the mass ratio q is 0.20(2). The superoutburst lasted between 8 and 12 days, peaked close to magnitude 13 with an amplitude above quiescence of 5 magnitudes, and faded for 4 days at a rate of 0.14 mag/d. Close monitoring following the end of the superoutburst detected a single normal outburst 60 days later which reached magnitude 14.7 and lasted less than 3 days.