UBVRI observations of the flickering of the dwarf nova RX And

TL;DR

This study presents multi-band observations of flickering in the dwarf nova RX And, revealing how brightness variations correlate with changes in the flickering source’s temperature and size.

Contribution

First detailed multi-band flickering analysis of RX And showing how brightness increases affect flickering source properties.

Findings

Flickering amplitude decreases as star brightens.

Flickering source radius roughly doubles during brightness increase.

Flickering source temperature slightly decreases with increased brightness.

Abstract

We report observations of the flickering variability of the dwarf nova RX And in five bands (UBVRI) on two nights. On 25 October 2019 the brightness of the star was $B\approx 13.9$ mag, the amplitude of the flickering was 0.47 mag, and we estimate for the flickering source temperature $T_{fl} = 10700 \pm 400$ K, and radius $R_{fl} =0.046 \pm 0.004$ $R_\odot$. On 2 January 2020, the star was about 3 magnitudes brighter ($B \approx 10.7$), the amplitude of the flickering was significantly lower (0.07 mag) and we derive for the flickering source $T_{fl} = 9600 \pm 700$ K, and radius $R_{fl} = 0.098 \pm 0.009$ $R_\odot$. The results indicate that 3 magnitudes brightening of the star doubled the radius of the flickering source. The data are available upon request from the authors.