Close binary systems Jean-Pierre Lasota Lecture 1.
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Transcript of Close binary systems Jean-Pierre Lasota Lecture 1.
Close binary systemsJean-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, 40-47 (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 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
Eclipsing X-ray binaries are very rare
Dip
Eclipse
Dips
Types of close binary systemsTypes of close binary systems
Equipotential surfaces in Roche geometry
- Euler equation
- Roche potential
. .1 2
Roche lobesRoche lobes
Flow of matter on the irradiated surface of a Roche-lobe filling star
Coriolis frequency Rossby number
V, L – velocity & length scales
When << 1 geostrophic flow: rotation important
Most close binaries have small eccentricities. This is not true of planets
Binary type Compact object Donor Comment
Cataclysmic binariesCataclysmic binaries White dwarf Red dwarfSubtypes : dwarf novae, novae
AM CVn binaryAM CVn binaryWhite dwarf White dwarf No H
Super Soft X-ray SourcesSuper Soft X-ray Sources White dwarf GiantSupersoft X soucres could be progenitors of SN Ia
Ultracompact X-ray BinariesUltracompact X-ray Binaries Neutron star White dwarf Shortest binary period: 11 min.
Low Mass X binariesLow Mass X binaries Neutron star or black holeM, K, G, F dwarfs or ou subgiants
All black hole X-ray binaries are transient
High Mass X-ray binariesHigh 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 binariesGamma-ray binaries Neutron star (pulsar) Supergiant Driven by rotation