Документ взят из кэша поисковой машины. Адрес оригинального документа : http://star.arm.ac.uk/lindsay/presentations/AJM.pdf Дата изменения: Tue Jan 30 14:41:28 2007 Дата индексирования: Tue Oct 2 05:09:37 2012 Кодировка: Поисковые слова: taurus

Outline

Introduction

Present Study

Conclusion

The influence of the environment on the propagation of protostellar outflows
Anthony Moraghan, Armagh Observatory
Lindsay Centennial Symposium

January 26, 2007
Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Outline
Introduction
Star Formation Numerical Jet Simulations Mass-velocity

Present study
Density Profile Preliminary Results

Conclusions

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Star Formation

Molecular Clouds

250pc to less than 1pc in extent Masses up to 106 M Densities 10- "Horsehead" nebula 430pc distant in Orion molecular cloud
19

kg/m

3

Mainly H2 with CO, H2 O, NH3 and `dust'

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Star Formation

Stages of Star Formation
1. Mainly H2 with CO, H2 O, NH3 and `dust' 2. Turbulence 3. Typical 100 M pc densities
-2

column

4. Core becomes opaque at 2в1010 H2 cm-3 5. M 6. M
env env

>M
star star

+M

disk

7. 'CTTS', Atomic Jets 8. `WTTS', optically visible
Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Star Formation

Outflow Observations

HH30 in Taurus Nebula HH47 in Gum Nebula.
Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Numerical Simulations

ZEUS-3D

Computational fluid dynamics code Grid based Semi-implicit molecular chemistry and cooling functions Expanded and improved for over 20 years Thoroughly tested so errors are known or have been ironed out

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Numerical Simulations

Jet Features

jet movie
Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Mass-Velocity

Mass-Velocity

Way to compare simulations directly to observations There is an inverse power law dependence between the mass of molecular gas (usually CO) with its true velocity Defined as m(v ) v
-

In words: Outflows always have a greater amount of mass moving at lower velocities than at higher velocities

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Mass-Velocity

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Density Profile

Density profile
Stars form in molecular cores Modify the ambient medium by adding a density profile den(i ) =
damb " " "" x 1(i ) 1+

where: `den' is the ambient medium density `damb' is the initial ambient medium density `x 1' is the position along the x-axis ` ' controls the size of a relatively uniform-density `core' region. `' is the power law exponent

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Density Profile

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Preliminary results

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Preliminary results

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Preliminary results

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Preliminary results

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium


Outline

Introduction

Present Study

Conclusion

Conclusions

Computer simulations provide a link between theory and observation Non-uniform ambient medium is closer to reality Any non-uniformity may lead to a small increase in the mass-velocity power-law

Anthony Moraghan, Armagh Observatory The influence of the environment on the propagation of protostellar outflows

Lindsay Centennial Symposium