1 / 34

clouds

The cycle of interstellar matter. 1. Formation of structures in the ISM. 2. ISM chemistry. clouds. filaments. filaments. debris. ISM. cores. 3. Star-formation. 4. Feedback. HII regions. planets. collapse. discs. jets. SNe. winds. 5. Discs evolution. T Tauri. stars.

cianna
Download Presentation

clouds

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. The cycle of interstellar matter 1. Formation of structures in the ISM 2. ISM chemistry clouds filaments filaments debris ISM cores 3. Star-formation 4. Feedback HII regions planets collapse discs jets SNe winds 5. Discs evolution T Tauri stars 6. Stars evolution

  2. Equipartition in the ISM Gravitation Radiation Cosmic rays Turbulence Magnetic fields Thermal pressure

  3. The cycle of interstellar matter 1. Formation of structures in the ISM 2. ISM chemistry clouds filaments filaments debris ISM cores 3. Star-formation 4. Feedback HII regions planets collapse discs jets SNe winds 5. Discs evolution T Tauri stars 6. Stars evolution

  4. ISM StructureThermal instability Characteristic lengths: Feedback Evolution, Leak Formation P. Lesaffre (2002, PhD thesis)

  5. Forming molecular clouds :the Thermal Instability P. Hennebelle, E. Audit Gravitation Cooling

  6. ISM Structure : MHD RAMSES MHD 500,000 CPU h Gravitation Cooling Magnetic field (Audit & Hennebelle 2005, Hennebelle et al. 2008, Klessen & Hennebelle 2010) FILAMENTARY rather than CLUMPY Clumps velocity dispersion Larson's relation

  7. Statistics inSimulations / Observations Magnetic field vs. density Troland & Heiles 1986 Mass spectrum Hennebelle & Audit 2007 Heithausen et al. 1998

  8. Pre-stellar cores Formation Press-Schechter + density PDF => Clumps mass function Hennebelle & Chabrier (2009) Schmidt et al. (2010) Comparison with high resolution numerical simulations without gravity No free parameter, but assumptions on PDF(r)

  9. 2. ISM Chemistry 1. Formation of structures in the ISM 1. Formation of structures in the ISM 2. ISM chemistry clouds filaments filaments debris ISM cores 3. Star-formation 4. Feedback HII regions planets collapse discs jets SNe winds Discs evolution T Tauri stars Star evolution

  10. SimpleISM molecular gas chemistry Form H2 molecules on grains. Then: H2 + H2+ → H3+ + X → XH+ + H2 H2 + X → XH + H where X is in {C, O, S, Si}. (N is an exception..)

  11. Form H2 molecules on grains. Then: H2 + (H2+) → H3+ + X → XH+ + H2 Needs ionisation (Cosmic rays, Irradiation) H2 + X → XH + H where X is in {C, O, S, Si}. (N is an exception..) SimpleISM molecular gas chemistry

  12. Form H2 molecules on grains. Then: H2 + (H2+) → H3+ + X → XH+ + H2 Needs ionisation (Cosmic rays, Irradiation) H2 + X (→) XH + H Needs thermal energy (Turbulence dissipation, mixing) where X is in {C, O, S, Si}. (N is an exception..) SimpleISM molecular gas chemistry

  13. MHD run post-processed by PDR Abundances computed by the PDR code in the XY plane Levrier et al. (2012) A significant fraction of the molecular region is not seen in CO, but rather traced by C or C+

  14. With the PDRs alone,we're missing some CO... Observations PDR post-processing Levrier et al. (2012)

  15. Turbulent dissipation and chemistry CHEMSES = DUMSES + chemistry G0=1 Av=0.1 1016 cm 32 species, 7 H2 levels 10242 pixels, decaying 2D turbulence, Urms~2 km/s P. Lesaffre

  16. Dissipation : various shapes and nature Dissipative heatings: Green: viscous Red: ohmic Blue: ion-neutral drift 2D Slice of a 5123 pseudo-spectral 3D incomressible MHD + A.D. Decaying turbulence from an Orzag-Tang vortex. Snapshot at peak dissipation. G. Momferratos

  17. Irradiation vs. DissipationTDR=vortices with ion-neutral drift B. Godard, E. Falgarone, G. Pineau des Forêts (2009)

  18. The cycle of interstellar matter 1. Formation of structures in the ISM 2. ISM chemistry clouds filaments filaments debris ISM cores 3. Star-formation 4. Feedback HII regions planets collapse discs jets SNe winds 5. Discs evolution T Tauri stars 6. Stars evolution

  19. Pre-stellar cores : Deuteration as a chemical clock Pagani et al. (2013) Observed D/H => o/p>0.2 => t_collapse < 4Myr 1D spherical collapse coupled with state by state chemistry. L183 (seen in core shine)

  20. Magnetised collapse weak B fragments strong B coherent (Note : importance of radiative transfer for massive cores) 100 M⊙ Commerçon Dziurkevich Joos Ciardi Hennebelle Levrier • Prospects : • ALMA • Chemistry • 2nd collapse Stellar cluster Massive star

  21. Collapse in non-aligned configuration Ciardi & Hennebelle (2010) B ejection   accretion RAMSES Aligned : strong braking, no disc Mis-aligned : disc and jet Joos et al. (2012)

  22. The cycle of interstellar matter 1. Formation of structures in the ISM 2. ISM chemistry clouds filaments filaments debris ISM cores 3. Star-formation 4. Feedback HII regions planets collapse discs jets SNe winds 5. Discs evolution T Tauri stars 6. Stars evolution

  23. (slides Sylvie)

  24. The cycle of interstellar matter 1. Formation of structures in the ISM 2. ISM chemistry clouds filaments filaments debris ISM cores 3. Star-formation 4. Feedback HII regions planets collapse discs jets SNe winds 5. Discs evolution T Tauri stars 6. Stars evolution

  25. Shearing Box

  26. Eruptive magnetised discs Lesaffre, Latter, Balbus (2009) Radial magnetic field ZEUS 3D, MHD Cooling Magneto-Rotational Instability Balbus Hawley (91)

  27. MRI in the earth core MagnetoStrophic-MRI instability with a helicoïdal field Petitdemange, Dormy, Balbus, PEPI submitted

  28. Dynamo effect : from earth to stars Varying the aspect ratio of the convective zone Goudard & Dormy, EPL, 2008 Schrinner, Petitdemange, Dormy, A&A, 2011 Schrinner, Petitdemange, Dormy, ApJ, 2012

  29. The cycle of interstellar matter 1. Formation of structures in the ISM 2. ISM chemistry clouds filaments filaments debris ISM cores 3. Star-formation 4. Feedback HII regions planets collapse discs jets SNe winds 5. Discs evolution T Tauri stars 6. Stars evolution

  30. Stellar interiors Sun's rotational contours S. Balbus • S. Balbus : S=f(W) Models for the internal Sun isorotationals • P. Lesaffre, K. Chitre, C. Tout : 2D convection models Angular momentum transport

  31. Stellar evolution MESA : Paxton et al. (2011) a single, freeware, ready to use Stellar evolution code for stars from brown dwarfs to very massive stars, from PMS to late evolution stages FLASH_THE_TORTOISE : Lesaffre et al. (2006) Late evolution stages of WD, Until the ignition of type Ia SNe.

  32. THANKS ! 1. Formation of structures in the ISM 2. ISM chemistry clouds filaments filaments debris ISM cores 3. Star-formation 4. Feedback HII regions planets collapse discs jets SNe winds 5. Discs evolution T Tauri stars 6. Stars evolution

  33. The magnetic field dissipationand turbulent transport... Radial magnetic field ZEUS 3D, MHD Cooling Magneto-Rotational Instability Balbus Hawley (91)

  34. ...determine the thermal structureof the disc ZEUS MHD Cooling Thermal diffusion Ohmic dissipation Viscous dissipation Towards a realistic Treatment of the Temperature - chemistry - dwarf novae - chondrules processing (P. Lesaffre) Temperature

More Related