Close binary systems Jean-Pierre Lasota Lecture 1
he light curve of Persei (Algol) – an eclipsing close binary
Al Ghoul
Persei
Doppler effect in stellar spectra.
Ellipsoidal variations See in Lasota, Scientific American, 280, part no 5, (1999)
Sizes
Tycho’s Nova (in fact a Supernova of type Ia – both novae and SNIa appear in close binaries containing white dwarfs.
a Nova outburst
The structure of a close binary
A black-hole low-mass X-ray binary
Outflows
A black-hole in a high-mass X-ray binary
Black hole X-ray binaries
Eclipsing X-ray binaries are very rare
Dip Eclipse
Dips
Types of close binary systems
Equipotential surfaces in Roche geometry - Euler equation - Roche potential.. 12
Roche lobes
Flow of matter on the irradiated surface of a Roche-lobe filling star Coriolis frequency Rossby number V, L – velocity & length scales When Ro << 1 geostrophic flow: rotation important
Most close binaries have small eccentricities. This is not true of planets
Binary typeCompact objectDonorComment Cataclysmic binaries White dwarfRed dwarf Subtypes : dwarf novae, novae AM CVn binary White dwarf No H Super Soft X-ray Sources White dwarfGiant Supersoft X soucres could be progenitors of SN Ia Ultracompact X-ray Binaries Neutron starWhite dwarf Shortest binary period: 11 min. Low Mass X binaries Neutron star or black hole M, K, G, F dwarfs or ou subgiants All black hole X-ray binaries are transient High Mass X-ray binaries Neutron star or black hole 0,B type supergiants or subgiants The neutron star is often an X-ray pulsar Gamma-ray binaries Neutron star (pulsar)SupergiantDriven by rotation