Simultaneous UBVRI observations of the cataclysmic variable AE Aquarii: temperature and mass of fireballs

TL;DR

This study provides simultaneous multicolor UBVRI observations of AE Aqr, estimating fireball parameters such as temperature, mass, and size during optical flares, enhancing understanding of the flare mechanisms in cataclysmic variables.

Contribution

It introduces detailed measurements of fireball properties during flares in AE Aqr using simultaneous multicolor observations, which is novel in capturing the physical parameters at flare peaks.

Findings

Fireballs have temperatures between 10,000 and 25,000 K.

Mass of fireballs ranges from 7 to 90 x 10^{19} g.

Fireball sizes are approximately 3 to 7 x 10^9 cm.

Abstract

We report simultaneous multicolour observations in 5 bands (UBVRI) of the flickering variability of the cataclysmic variable AE Aqr. Our aim is to estimate the parameters (colours, temperature, size) of the fireballs that produce the optical flares. The observed rise time of the optical flares is in the interval 220 - 440 sec. We estimate the dereddened colours of the fireballs: (U-B)_0 in the range 0.8-1.4, (B-V)_0 ~ 0.03-0.24, (V-I)_0 ~ 0.26-0.78. We find for the fireballs a temperature in the range 10000 - 25000 K, mass (7-90).10^{19} g, size (3-7).10^9 cm (using a distance of d=86 pc). These values refer to the peak of the flares observed in UBVRI bands. The data are available upon request from the authors.