EX Dra

An Eclipsing Cataclysmic Variable Star

EX Draconis (EX Dra) is an Eclipsing Dwarf Nova, which is a type of Cataclysmic Variable star. It's a close binary system consisting of a White Dwarf and a low-mass companion star that feeds material into an Accretion Disk. This system is observed nearly edge-on, meaning its orbit is highly inclined ($\sim 85^\circ$) to our line of sight. This high inclination causes the companion star to periodically and significantly eclipse the bright White Dwarf, the accretion disk, and the hotspot, which allows astronomers to measure the system's parameters with high precision. In addition to these regular eclipses, EX Dra exhibits typical Dwarf Nova outbursts where its brightness increases temporarily. Its orbital period is about 5.04 hours.

Photometry & Images

Catalogue Gaia
RA 271.059770938°
DEC 67.903456022°
U --
B --
V --
Parallax (mas) 4.15 ± 0.02
Light curve

TESS Data

20 16 17

AAVSO Data

aavsodataimage

Spectroscopy

Spectrum of EX Dra

References

1. Liu W. et al. The Photometric Study of EX Dra: A Dwarf Nova Exhibiting a Titled and Precessional Disk //The Astrophysical Journal. – 2024. – Т. 974. – №. 1. – С. 130.

2. Baptista R., Catalán M. S., Costa L. Eclipse studies of the dwarf nova EX Draconis //Monthly Notices of the Royal Astronomical Society. – 2000. – Т. 316. – №. 3. – С. 529-539.

3. Baptista R., Catalán M. S. Changes in the structure of the accretion disc of EX Draconis through the outburst cycle //Monthly Notices of the Royal Astronomical Society. – 2001. – Т. 324. – №. 3. – С. 599-611.