ASTRONOMY: DQ Herculis System

Magnetic Cataclysmic Variable: DQ Herculis System. This image is 600 x 445 pixels; the original measures 4,015 x 2,975 pixels.

Intermediate Polar or DQ Herculis System. An M-dwarf star loses material to a white dwarf star. The material forms an accretion stream before swirling into an accretion disc. As the material in the accretion disc approaches the magnetic white dwarf, it is swept up by the magnetic field of the white dwarf forming accretion curtains which follow the magnetic lines of force. The magnetosphere of the white dwarf is tilted with respect to the orbital plane, causing the accretion curtain to split, the material following the shortest route along the magnetosphere. The material then crashes into the magnetic poles of the white dwarf, causing strong X-ray emissions.

Research at the Australian National University on MCVs White Dwarf Stars, AM Hers, IPs etc.

VARIABLE STAR OF THE MONTH June 2001 AM Herculis: article by the AAAVSO the American Association of Variable Star Observers.

• Magnetic: contain a magnetic white dwarf.
• Cataclysmic: at regular intervals, the infalling material triggers a runaway thermonuclear reaction at the surface of the white dwarf. Such a violent explosion is called a cataclysm.
• Variable: the impact point of the infalling material on the white dwarf gives off a great deal of radiation. As the system rotates, so this hot spot periodically comes into view, giving an apparently variable output to the system.