76
CVs:
Short Period Systems
€CVs with main sequence secondaries have minimum orbital
period of 80 minutes
€However, some accreting binaries are seen to have shorter periods
Þ
the secondaries must be white dwarfs,
or perhaps the
degenerate
core of a giant which has been stripped away
€However, some accreting binaries are seen to have shorter periods
Þ
the secondaries must be white dwarfs,
or perhaps thedegenerate
core of a giant which has been stripped away€The optical spectra of these systems show only Helium (no
Hydrogen)
GP
Com
€The disk behaviour is different because of the different ionisation of He compared to He; interesting astrophysical laboratories
€Orbital periods from ~65 min to ~15 min
€Known as the AM CVn systems
€Orbital periods from ~65 min to ~15 min
€Known as the AM CVn systems
Marsh, Horne & Rosen (1991)