Contact Binary White Dwarfs Exchanging Matter

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Contact Binary White Dwarfs Exchanging Matter

• Joel E. Tohline
• Department of Physics Astronomy
• Louisiana State University
• http//www.phys.lsu.edu/tohline

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Likely Origin of Double White Dwarf (DWD) Systems
NGC 2346 Planetary Nebula whose central object
is actually a compact binary star system whose
orbital period is 16 days.
Implies the two stars are in an orbit with a
separation, a 30 R.
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Broader Class of Cataclysmic Variables
Note AM Her ? P 3.1 hr
Taken from Hamburg Quasar Survey
http//www.hs.uni-hamburg.de/EN/For/Exg/Sur/hqs/p
rojects/cvs/CA_newsletter/index.html
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Broader Class of Cataclysmic Variables
Note AM Her ? P 3.1 hr
Taken from Hamburg Quasar Survey
http//www.hs.uni-hamburg.de/EN/For/Exg/Sur/hqs/p
rojects/cvs/CA_newsletter/index.html
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Observational Properties of DWD Binaries
Taken from G. Nelemans article
http//xxx.lanl.gov/abs/astro-ph/0409676
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Observational Properties of DWD Binaries
Taken from G. Nelemans article
http//xxx.lanl.gov/abs/astro-ph/0409676
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AM CVn

• Porb 1029 s
• r 235 pc 766 light-years
• Mtot 0.8 M
• q Mdonor/Maccretor 0.1
• a orbital separation 0.2 R 22 RÅ
• Rdonor 4.4 RÅ Raccretor 2 RÅ

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AM CVn

• Porb 1029 s
• r 235 pc 766 light-years
• Mtot 0.8 M
• q Mdonor/Maccretor 0.1
• a orbital separation 0.2 R 22 RÅ
• Rdonor 4.4 RÅ Raccretor 2 RÅ

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AM CVn against the Sun
Taken from http//www.refractormonkey.com/solar.
htm
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AM CVn against the Sun
Taken from http//www.refractormonkey.com/solar.
htm
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AM CVn against a sunspot!
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AM CVn against the Sun
Taken from http//www.refractormonkey.com/solar.
htm
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Close Binary showing Roche Lobe
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Numerical Simulations
SuperMike LSUs 1024-processor, 3 TeraFlop
Supercomputer
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Initial Configurations
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Play Movies !!
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Summer 2005 issue of NCSAs Access Magazine
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DWD Systems as Sources of Gravitational Radiation
Taken from http//lisa.jpl.nasa.gov/gallery/ligo
-lisa.html
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Gravitational-Wave Signal Strength
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Gravitational-Wave Signal Strength

• h hnorm sin(2pf t)

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Gravitational-Wave Signal Strength

• h hnorm sin(2pf t)
• hnorm 4 Q(GM)2/(c4 r a) (1 t/tchirp)-1/4
• f GM/(p2a3)1/2 (1 t/tchirp)-3/8

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Gravitational-Wave Signal Strength

• h hnorm sin(2pf t)
• hnorm 4 Q(GM)2/(c4 r a) (1 t/tchirp)-1/4
• f GM/(p2a3)1/2 (1 t/tchirp)-3/8
• tchirp 5 c5a4/(256 Q G3M3)
• Q q/(1 q)2

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Gravitational-Wave Signal Strength

• h hnorm sin(2pf t)
• hnorm 4 Q(GM)2/(c4 r a) (1 t/tchirp)-1/4
• f GM/(p2a3)1/2 (1 t/tchirp)-3/8
• tchirp 5 c5a4/(256 Q G3M3)
• Q q/(1 q)2
• a GM(P/2p)21/3

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AM CVn

• Porb 1029 s
• r 235 pc 766 light-years
• Mtot 0.8 M
• q Mdonor/Maccretor 0.1
• a orbital separation 0.2 R 22 RÅ
• Rdonor 4.4 RÅ Raccretor 2 RÅ

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DWD Systems as Sources of Gravitational Radiation
Taken from http//lisa.jpl.nasa.gov/gallery/ligo
-lisa.html
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DWD Systems as Sources of Gravitational Radiation
Taken from http//lisa.jpl.nasa.gov/gallery/ligo
-lisa.html