1 / 16

Studies of Molecular Outflows

Studies of Molecular Outflows. Hsin-Lun Kuo Department of Physics,NTU Supervisor:Hsien Shang 2002 Summer Students Presentation, ASIAA. Outline. Bipolar Molecular Outflows of YSOs A Simple Physical Model Based on “Star Formation And The Nature Of Bipolar Outflows ”,

hila
Download Presentation

Studies of Molecular Outflows

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. Studies of Molecular Outflows Hsin-Lun Kuo Department of Physics,NTU Supervisor:Hsien Shang 2002 Summer Students Presentation, ASIAA

  2. Outline • Bipolar Molecular Outflows of YSOs • A Simple Physical Model Based on “Star Formation And The Nature Of Bipolar Outflows”, Shu et al., ApJ 370, March 1991 • Try To Produce Different Shapes of The Lobes Summer Students,ASIAA

  3. Bipolar Molecular Outflows of YSOs • Deeply related to the processes of star formation and early stellar evolution • Observable from UV to radio, best traced by CO emission • Flow sizes: less than 0.1pc ~ several pc • Terminal velocities: a few kms-1 ~ several hundred kms-1 • Kinematical time-scale: 103 ~ 105 yr • Outflowing mass: 10-2 M ~ 102 M Summer Students,ASIAA

  4. Properties of Outflows • Intrinsic or external, large-scale collimation? • “Classical” and “highly collimated” outflows in observations • Collimation factor--axial ratio • Hubble-like law • Jet-like and EHV bullets • Class I and Class 0 YSOs Summer Students,ASIAA

  5. Shu’s “Snowplow” Model • Radiating shocks form a swept-up shell of ambient molecular cloud material • Swept-up and shocked-wind material mixed well • Momentum-driven • Intrinsically collimated by MHD mechanism Summer Students,ASIAA

  6. Equations • Density distribution of an isothermal sphere • Momentum input per steradian Summer Students,ASIAA

  7. Solutions • For momentum conserved winds blowing into 1/r2 density profiles Shell speed Shell position Bipolarity function Summer Students,ASIAA

  8. Constraints • Q(μ) : • P(μ) : • B(μ) : and and and Axial ratio of lobe Summer Students,ASIAA

  9. My “Guess” on P(μ), Q(μ) B(μ) Q(μ) μ P(μ) μ μ Summer Students,ASIAA

  10. Reproducing The Lobes • Axial ratio 3:1 (with [f/2]1/2=0.4 , avw=100 ) Summer Students,ASIAA

  11. Some Trials– 2:1 Q(μ) μ P(μ) μ Summer Students,ASIAA

  12. Some Trials – 4:1 Q(μ) μ P(μ) μ Summer Students,ASIAA

  13. Some Trials – 5:1 Q(μ) μ P(μ) μ Summer Students,ASIAA

  14. Some Trials – 8:1 Q(μ) μ P(μ) μ Summer Students,ASIAA

  15. Some Trials – 10:1 Q(μ) μ P(μ) μ Summer Students,ASIAA

  16. Future Work • Change a few constraints • Make more realistic guesses on P,Q • Considering f , a , vw , t • Compare to observational results of simple outflows Summer Students,ASIAA

More Related