1 / 113

Merger Simulations (examining the onset and outcome of various instabilities)

Merger Simulations (examining the onset and outcome of various instabilities). Joel E. Tohline Louisiana State University. Collaborators: J. Frank, P. Motl , W. Even, D. Marcello, G. Clayton, C. Fryer, S. Diehl. Part I: Broad Context. Double White Dwarfs (DWDs). Binary System Parameters

read
Télécharger la présentation

Merger Simulations (examining the onset and outcome of various instabilities)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Merger Simulations(examining the onset and outcome of various instabilities) Joel E. Tohline Louisiana State University Collaborators: J. Frank, P. Motl, W. Even, D. Marcello, G. Clayton, C. Fryer, S. Diehl

  2. Part I: Broad Context LSU: Physics & Astronomy Colloquium

  3. Double White Dwarfs (DWDs) LSU: Physics & Astronomy Colloquium

  4. Binary System Parameters (circular orbit; point-mass system) LSU: Physics & Astronomy Colloquium

  5. Binary System Parameters (circular orbit; point-mass system) Sufficient to specify: M, q, Porb LSU: Physics & Astronomy Colloquium

  6. Binary System Parameters (circular orbit; WD mass-radius relationship) M2 M1 R2 a R1 LSU: Physics & Astronomy Colloquium

  7. Binary System Parameters (circular orbit; WD mass-radius relationship) M2 M1 R2 a R1 LSU: Physics & Astronomy Colloquium

  8. Binary System Parameters (mass-transfer system) M2 donor M1 R2 a R1 LSU: Physics & Astronomy Colloquium

  9. Binary System Parameters (circular orbit; point-mass system) Sufficient to specify: M, q, Porb LSU: Physics & Astronomy Colloquium

  10. (slide stolen from this past Friday’s talk by Nelemans) Lorentz Center: Stellar Mergers

  11. (slide stolen from this past Friday’s talk by Nelemans) Lorentz Center: Stellar Mergers

  12. Possible Mtot - q0Distribution at Birth[borrowing Hurley’s population synthesis code (2002)] Lorentz Center: Stellar Mergers

  13. Gravitational-Wave Detectors LSU: Physics & Astronomy Colloquium

  14. Laser Interferometer Gravitational-wave Observatory (LIGO) Hanford Observatory Livingston Observatory LSU: Physics & Astronomy Colloquium

  15. Laser Interferometer Gravitational-wave Observatory (LIGO)

  16. Gravitational-Wave Signalcharacterized by amplitude “h” and frequency “f” LSU: Physics & Astronomy Colloquium

  17. Gravitational-Wave Signalcharacterized by amplitude “h” and frequency “f” From GR quadrupole radiation formula (e.g., Peters & Mathews 1963) LSU: Physics & Astronomy Colloquium

  18. Classic “chirp” Signaldue to point-mass binary inspiral From GR quadrupole radiation formula (e.g., Peters & Mathews 1963) LSU: Physics & Astronomy Colloquium

  19. Classic “chirp” Signaldue to point-mass binary inspiral From GR quadrupole radiation formula (e.g., Peters & Mathews 1963) LSU: Physics & Astronomy Colloquium

  20. Classic “chirp” Signaldue to point-mass binary inspiral During inspiral: h ~ f2/3 From GR quadrupole radiation formula (e.g., Peters & Mathews 1963) LSU: Physics & Astronomy Colloquium

  21. High-Frequency Sources of Gravitational Radiation Taken from … http://lisa.jpl.nasa.gov/gallery/ligo-lisa.html LSU: Physics & Astronomy Colloquium

  22. Binary Orbital Parameters AM CVn Hulse-Taylor pulsar LSU: Physics & Astronomy Colloquium

  23. Binary Orbital Parameters AM CVn Hulse-Taylor pulsar LSU: Physics & Astronomy Colloquium

  24. Radiation from Hulse-Taylor Pulsar Taken from … http://lisa.jpl.nasa.gov/gallery/ligo-lisa.html LSU: Physics & Astronomy Colloquium

  25. Binary Orbital Parameters AM CVn Hulse-Taylor pulsar LSU: Physics & Astronomy Colloquium

  26. Binary Orbital Parameters AM CVn Hulse-Taylor pulsar LSU: Physics & Astronomy Colloquium

  27. Low-Frequency Sources of Gravitational Radiation Taken from … http://lisa.jpl.nasa.gov/gallery/ligo-lisa.html LSU: Physics & Astronomy Colloquium

  28. Laser-Interferometer Space Antenna (LISA) LSU: Physics & Astronomy Colloquium

  29. High-Frequency Sources of Gravitational Radiation Taken from … http://lisa.jpl.nasa.gov/gallery/ligo-lisa.html LSU: Physics & Astronomy Colloquium

  30. DWD Orbit Evolutionsin LISA’s Strain-Frequency Domain [Kopparapu & Tohline (2007)] LSU: Physics & Astronomy Colloquium

  31. DWD Evolutionary Trajectories(for given “q”) “detached” inspiral “mass-transferring” out-spiral LSU: Physics & Astronomy Colloquium

  32. DWD Evolutionary Trajectories(for given “q”) LSU: Physics & Astronomy Colloquium

  33. DWD Evolutionary Trajectories(for given “q”) “detached” inspiral “mass-transferring” out-spiral LSU: Physics & Astronomy Colloquium

  34. DWD Evolutionary Trajectories(for given “q”) LSU: Physics & Astronomy Colloquium

  35. DWD Evolutionary Trajectories(for given “q”) LSU: Physics & Astronomy Colloquium

  36. Part II: This Work LSU: Physics & Astronomy Colloquium

  37. General Context of this Work • Onset and nonlinear development of mass-transfer in Double White Dwarf (DWD) binaries • Initiated by Roche Lobe Overflow (RLOF) • Followed through £ 40 orbits. • Self-consistent, 3D Newtonian hydrodynamic modeling of mass-transfer (and merger) using a finite-volume “grid” code, not SPH • The stars have comparable radii, so you’ll see “direct impact” rather than “disk” accretion Lorentz Center: Stellar Mergers

  38. General Context of this Work • Onset and nonlinear development of mass-transfer in Double White Dwarf (DWD) binaries • Initiated by Roche Lobe Overflow (RLOF) • Followed through £ 40 orbits. • Self-consistent, 3D Newtonian hydrodynamic modeling of mass-transfer (and merger) using a finite-volume “grid” code, not SPH • The stars have comparable radii, so you’ll see “direct impact” rather than “disk” accretion Lorentz Center: Stellar Mergers

  39. General Context of this Work • Onset and nonlinear development of mass-transfer in Double White Dwarf (DWD) binaries • Initiated by Roche Lobe Overflow (RLOF) • Followed through £ 40 orbits. • Self-consistent, 3D Newtonian hydrodynamic modeling of mass-transfer (and merger) using a finite-volume “grid” code, not SPH • The stars have comparable radii, so you’ll see “direct impact” rather than “disk” accretion Lorentz Center: Stellar Mergers

  40. General Context of this Work • Onset and nonlinear development of mass-transfer in Double White Dwarf (DWD) binaries • Initiated by Roche Lobe Overflow (RLOF) • Followed through £ 40 orbits. • Self-consistent, 3D Newtonian hydrodynamic modeling of mass-transfer (and merger) using a finite-volume “grid” code, not SPH • The stars have comparable radii, so you’ll see “direct impact” rather than “disk” accretion Lorentz Center: Stellar Mergers

  41. General Context of this Work • Onset and nonlinear development of mass-transfer in Double White Dwarf (DWD) binaries • Initiated by Roche Lobe Overflow (RLOF) • Followed through £ 40 orbits. • The stars have comparable radii, so you’ll see “direct impact” rather than “disk” accretion • Self-consistent, 3D Newtonian hydrodynamic modeling of mass-transfer (and merger) using a finite-volume “grid” code, not SPH Lorentz Center: Stellar Mergers

  42. General Context of this Work • Onset and nonlinear development of mass-transfer in Double White Dwarf (DWD) binaries • Initiated by Roche Lobe Overflow (RLOF) • Followed through £ 40 orbits. • The stars have comparable radii, so you’ll see “direct impact” rather than “disk” accretion • Self-consistent, 3D Newtonian hydrodynamic modeling of mass-transfer (and merger) using a finite-volume “grid” code, not SPH Lorentz Center: Stellar Mergers

  43. Pure Hydro 0; 0 ; Lorentz Center: Stellar Mergers

  44. General Context of this Work • Equation of state: While we have used a zero-temperature white dwarf (ZTWD) EOS, here I will show only n = 3/2 polytropic (g = 5/3 adiabatic) flows • a reasonably good approximation for low-mass white dwarfs • broadly appealing because polytropes are scale-free • Effects of photon radiation ignored (until very recently) • Keeping the “micro-physics” simple … • makes it easier to pinpoint what physics is responsible for the dynamical features that arise in a given simulation • Makes it easier to ascertain what is physics and what is purely numerical Lorentz Center: Stellar Mergers

  45. General Context of this Work • Equation of state: While we have used a zero-temperature white dwarf (ZTWD) EOS, here I will show only n = 3/2 polytropic (g = 5/3 adiabatic) flows • a reasonably good approximation for low-mass white dwarfs • broadly appealing because polytropes are scale-free • Effects of photon radiation ignored (until very recently) • Keeping the “micro-physics” simple … • makes it easier to pinpoint what physics is responsible for the dynamical features that arise in a given simulation • Makes it easier to ascertain what is physics and what is purely numerical Lorentz Center: Stellar Mergers

  46. General Context of this Work • Equation of state: While we have used a zero-temperature white dwarf (ZTWD) EOS, here I will show only n = 3/2 polytropic (g = 5/3 adiabatic) flows • a reasonably good approximation for low-mass white dwarfs • broadly appealing because polytropes are scale-free • Effects of photon radiation ignored (until very recently) • Keeping the “micro-physics” simple … • makes it easier to pinpoint what physics is responsible for the dynamical features that arise in a given simulation • Makes it easier to ascertain what is physics and what is purely numerical Lorentz Center: Stellar Mergers

  47. General Context of this Work • Equation of state: While we have used a zero-temperature white dwarf (ZTWD) EOS, here I will show only n = 3/2 polytropic (g = 5/3 adiabatic) flows • a reasonably good approximation for low-mass white dwarfs • broadly appealing because polytropes are scale-free • Effects of photon radiation ignored (until very recently) • Keeping the “micro-physics” simple … • makes it easier to pinpoint what physics is responsible for the dynamical features that arise in a given simulation • Makes it easier to ascertain what is physics and what is purely numerical Lorentz Center: Stellar Mergers

  48. General Context of this Work • Equation of state: While we have used a zero-temperature white dwarf (ZTWD) EOS, here I will show only n = 3/2 polytropic (g = 5/3 adiabatic) flows • a reasonably good approximation for low-mass white dwarfs • broadly appealing because polytropes are scale-free • Effects of photon radiation ignored (until very recently) • Keeping the “micro-physics” simple … • makes it easier to pinpoint what physics is responsible for the dynamical features that arise in a given simulation • Makes it easier to ascertain what is physics and what is purely numerical Lorentz Center: Stellar Mergers

  49. General Context of this Work • Equation of state: While we have used a zero-temperature white dwarf (ZTWD) EOS, here I will show only n = 3/2 polytropic (g = 5/3 adiabatic) flows • a reasonably good approximation for low-mass white dwarfs • broadly appealing because polytropes are scale-free • Effects of photon radiation ignored (until very recently) • Keeping the “micro-physics” simple … • makes it easier to pinpoint what physics is responsible for the dynamical features that arise in a given simulation • Makes it easier to ascertain what is physics and what is purely numerical Lorentz Center: Stellar Mergers

  50. Some Theoretical Considerations • “Darwin Instability” • Has been mentioned several different times over the course of this workshop as relevant to mergers (e.g., DWDs and WUMa systems) • Point along a (synchronously rotating) binary inspiral sequence at which Jtot and Etot reach a minimum • Any further loss of angular momentum (inspiral) leads to secular instability loss of synchronous rotation and, perhaps, tidal disruption/merger Lorentz Center: Stellar Mergers

More Related