outflows and jets: theory and observations · outflows and jets: theory and observations winter...
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Outflows and Jets: Theory and Observations Winter term 2008/2009
Henrik Beuther & Christian Fendt 10.10 Today: Introduction & Overview (C.F.) 17.10 Definitions, parameters, basic observations (H.B.) 24.10 Basic theoretical concepts & models (C.F.) 31.10 Basic MHD and plasma physics; applications (C.F.) 07.11 Observational properties of accretion disks (H.B.) 14.11 Accretion disk theory and jet launching (C.F.) 21.11 Outflow-disk connection, outflow entrainment (H.B.) 28.11 Outflow-ISM interaction, outflow chemistry (H.B.) 05.12 Theory of outflow interactions: Instabilities, shocks (C.F.) 12.12 Outflows from massive star-forming regions (H.B.) 19.12 Radiation processes I (C.F.) 26.12 and 02.01 Christmas and New Years break 09.01 Radiation processes II (H.B.) 16.01 Observations of AGN jets (C.F.) 23.01 Some aspects of AGN jet theory (C.F.) 30.01 Summary, Outlook, Questions (H.B. & C.F.)
More Information and the current lecture files: http://www.mpia.de/homes/beuther/lecture_ws0809.html [email protected], [email protected]
Topics today
- Importance, difficulties, potentials & early observational claims
- Single-dish results at relatively low spatial resolution
- Interferometric high-spatial resolution observations and their implications
- Infall and outflow around ultracompact HII regions
- The most famous massive outflow in Orion-KL
Optisch
Importance of massive stars
Great impact on ISM and star clusters, L∝M3
- Outflows and Jets
- UV-radiation
- Supernovae
- The majority of all stars form in clusters, massive stars exclusively.
- They produce all heavy elements
- Only star formation at high-Z that is observable.
Problem: With the typical accretion rates known from low-mass star formation, the radiation pressure of the forming massive stars would revert any infall for protostars >10Msun.
Massive Star Formation Modified classical scenario: Wolfire & Cassinelli 1987 Jijina & Adams 1996 Yorke & Sonnhalter 2002 Norberg & Maeder 2002 Keto 2002, 2003 Krumholz et al. 2005, 2006 Banerjee & Pudritz 2005
Coalescence and competitive accretion scenario: Bonnell et al. 1998, 2004, 2004 Stahler et al. 2000 Bally & Zinnecker 2005
Bally & Zinnecker 2005
Pudritz & Banerjee 2005
How to differentiate between both scenario? - Molecular outflows and accretion disks - Fragmentation and global collapse - …
Bonnell et al. 2007
Flashlight effect
- With outflow cavities the average gas temperatures are cooler. - Gravitational force stronger in eq. plane. - Radiation escapes through outflow cavities. --> Reduction of radiation pressure and angular momentum problem.
Black: gravity Red: no cavity Green, blue, purple: 5, 10, 15o opening angle θ are the different angles from the pole. b represents different cavity shapes.
Krumholz et al. 2005 (also Yorke & Sonnhalter 2002)
Results of early massive outflow research
Seem to be ubiquitous phenomena
Very massive and energetic
Seemingly less collimated than low-mass flows
Different entrainment scenarios proposed (deflection, winds...)
However, these results were based on small samples and poor angular resolution (between 21'' and 60'')
Shepherd et al. 1996a,b, Churchwell et al. 1997
Results of early massive outflow research
Seem to be ubiquitous phenomena
Very massive and energetic
Seemingly less collimated than low-mass flows
Different entrainment scenarios proposed (deflection, winds...)
However, these results were based on small samples and poor angular resolution (between 21'' and 60'')
Shepherd et al. 1996a,b, Churchwell et al. 1997
Schulz et al.1999
Results of early massive outflow research
Seem to be ubiquitous phenomena
Very massive and energetic
Seemingly less collimated than low-mass flows
Different entrainment scenarios proposed (deflection, winds...)
However, these results were based on small samples and poor angular resolution (between 21'' and 60'')
Shepherd et al. 1996a,b, Churchwell et al. 1997
Schulz et al.1999
Shepherd et al. 1996
Results of early massive outflow research
Seem to be ubiquitous phenomena
Very massive and energetic
Seemingly less collimated than low-mass flows
Different entrainment scenarios proposed (deflection, winds...)
However, these results were based on small samples and poor angular resolution (between 21'' and 60'')
Shepherd et al. 1996a,b, Churchwell et al. 1997
Results of early massive outflow research
Seem to be ubiquitous phenomena
Very massive and energetic
Seemingly less collimated than low-mass flows
Different entrainment scenarios proposed (deflection, winds...)
However, these results were based on small samples and poor angular resolution (between 21'' and 60'')
Shepherd et al. 1996a,b, Churchwell et al. 1997
Model idea: Churchwell 1997 Plot: Arce et al. 2007
Topics today
- Importance, difficulties, potentials & early observational claims
- Single-dish results at relatively low spatial resolution
- Interferometric high-spatial resolution observations and their implications
- Infall and outflow around ultracompact HII regions
- The most famous massive outflow in Orion-KL
Massive molecular outflow maps
- Assuming momentum conservation: pout = Moutvout = Mjetvjet = dMjet/dt vjett = pjet - With a jet/outflow velocity ratio vjet/vout~20 and a ratio of outflow rate to the accretion rate of ~0.3, one can estimate accretion rates: --> Mean accretion rate 10-4 Msun/year high enough to overcome radiation pressure
Grey: 1.2mm cont., Contours: CO(2-1)
IRAM 30m, Beam 11''
Beuther et al. 2002
Outflow masses versus core masses
Accretion rate: Macc = facc Mcore/tff deflection efficiency: fr = Mjet/Macc
.
. .
Multiply both equations and assume momentum conservation frfacc = Mjet/Mcore = vout/vjet x Mout/Mcore = constant
Macc is approximately a linear function of Mcore (and the mass of the outflow is proportional to the core mass)
.
Beuther et al. 2002
Accretion rates vs protostellar mass
Zhang 2005
Infall and accretion rates overestimated?
Outflow properties
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Topics today
- Importance, difficulties, potentials & early observational claims
- Single-dish results at relatively low spatial resolution
- Interferometric high-spatial resolution observations and their implications
- Infall and outflow around ultracompact HII regions
- The most famous massive outflow in Orion-KL
The pre-UCHII region IRAS05358+3543
Beuther et al. 2002
IRAM 30m data Grey: 1.2mm Contours:CO(2-1)
Lbol ~ 6.3x103 Lsun; no cm emission --> pre-UCHII region
IRAM 30m, CO(2-1), Beam 11''
The Outflows in IRAS 19410+2336
PdBI + 30m, CO(1-0), Beam 3.9'' x 3.6''
blue wing red wing both
Beuther et al. 2003
Lbol ~ 6.3x103 Lsun; very weak cm emission --> HCHII region, pre-UCHII region
Shocked H2 emission in IRAS 18151-1208
Lbol ~ 2x104 Lsun no cm emission pre-UCHII region
Spectroscopy of the H2 features reveals similar characteristics to low- mass outflows
Davis et al. 2004, Fallscheer et al. in prep.
Color: H2 Contours: 875µm
A centimeter continuum jet in IRAS 16547-4247
8.4 GHz
K-band & 1.2mm
Lbol ~6x104 Lsun
Collimated thermal & non-thermal jet
Brooks et al. 2003 Graray et al. 2003
A young UCHII region: G192
Shepherd et al. 1998, 1999 Devine et al. 1999
[SII]
Color contours: CO(1-0) Inlay: mm continuum
Lbol ~ 3x103 Lsun
Small UCHII at center
Collimation con- sistent with wind- blown bubble
The UCHII region W75
Shepherd et al. 2003, 2004
Torrelles et al. 2003
Cluster of B0.5 to B2 stars associated with UCHIIs
Lbol ~ 4x104 Lsun
Wide-angle large-scale outflow, is that associated with the small-scale maser outflows?
The luminous UCHII region G5.89
Lbol ~ 3x105 Lsun Harbours O5 star
Multiple outflows
Sollins et al. 2004 Watson et al. 2002 Feldt et al. 2003 Puga et al. 2006
Position velocity diagrams 19217+1651 23033+5951
20126+4104 20293+3952
Beuther et al. 2004
Position velocity diagrams 19217+1651 23033+5951
20126+4104 20293+3952
Beuther et al. 2004
Position velocity diagrams 19217+1651 23033+5951
20126+4104 20293+3952
Beuther et al. 2004
Position velocity diagrams 19217+1651 23033+5951
20126+4104 20293+3952
Beuther et al. 2004
IRAS20126+4104, Lebron et al. 2006
Position velocity diagrams 19217+1651 23033+5951
20126+4104 20293+3952
Beuther et al. 2004
Position velocity diagrams 19217+1651 23033+5951
20126+4104 20293+3952
Beuther et al. 2004
In principle, all pv-diagrams appear reproducable via jet-entrainment and/or wide-angle winds, similar to the low-mass outflows.
(Yorke 2004)
W75 N
G192.16
IRAS 20126
IRAS 05358
ZAMS No real jet with UCHIIs
Pre-ZAMS & Pre-UCHII Jet-like outflows
Adapted from Shepherd 2004
Approximate Timescales for massive outflows
An evolutionary scenario
Beuther & Shepherd 2005
Possible reasons: Stellar wind, magnetic diffusivity, ionized radiation?
Topics today
- Importance, difficulties, potentials & early observational claims
- Single-dish results at relatively low spatial resolution
- Interferometric high-spatial resolution observations and their implications
- Infall and outflow around ultracompact HII regions
- The most famous massive outflow in Orion-KL
Rotation, Infall and Outflow motions
Beltran et al. 2006, 2007
Grey: 7mm HCHII White dots: H2O maser
The very luminous UCHII region G10.6-0.4
1.3cm continuum
Rotation/infall axis
Outflow axis
Keto 2002, 2005 Sollins et al. 2005
H66α recomb. line
NH3(3,3)
H66α 1st moment Infall in mol. and ionized gas.
Outflow in ionized gas Perpendicular.
The very luminous UCHII region G10.6-0.4
1.3cm continuum
Rotation/infall axis
Outflow axis
Keto 2002, 2005 Sollins et al. 2005
H66α recomb. line
NH3(3,3)
H66α 1st moment Infall in mol. and ionized gas.
Outflow in ionized gas Perpendicular.
Topics today
- Importance, difficulties, potentials & early observational claims
- Single-dish results at relatively low spatial resolution
- Interferometric high-spatial resolution observations and their implications
- Infall and outflow around ultracompact HII regions
- The most famous massive outflow in Orion-KL
The most famous Orion-KL outflow Color: MIR (Greenhill et al.) Contours: 865µm (Beuther et al.)
The most famous Orion-KL outflow Color: MIR (Greenhill et al.) Contours: 865µm (Beuther et al.)
Schulz et al.1999
The most famous Orion-KL outflow Color: MIR (Greenhill et al.) Contours: 865µm (Beuther et al.)
Schulz et al.1999
Tan 2004
The most famous Orion-KL outflow Color: MIR (Greenhill et al.) Contours: 865µm (Beuther et al.)
Schulz et al.1999
Gomez et al. 2008
C18O(2-1) SMA+30m channel map
Beuther & Nissen 2008
The two Orion-KL outflows and their potential driving sources
Grey: H2 Contours: C18O
Color: 865µm Contours: SiO(8-7)
Beuther & Nissen 2008
Summary Massive molecular outflows are ubiquitous phenomena.
Jet-like outflows exists at least up to early-B and late-O-type stars.
Like in low-mass star formation, some outflows are likely driven by jet-entrainment whereas others are consistent with wide-angle winds.
Estimated accretion rates are high enough to overcome radiation pressure.
Flashlight effect additional helps reducing radiation pressure in equatorial plane.
Hence the observations support the classical scenario that massive star formation proceeds similarly to low-mass star formation.
The observations suggests tentatively an evolutionary scenario.
Outflows and Jets: Theory and Observations Winter term 2008/2009
Henrik Beuther & Christian Fendt 10.10 Today: Introduction & Overview (C.F.) 17.10 Definitions, parameters, basic observations (H.B.) 24.10 Basic theoretical concepts & models (C.F.) 31.10 Basic MHD and plasma physics; applications (C.F.) 07.11 Observational properties of accretion disks (H.B.) 14.11 Accretion disk theory and jet launching (C.F.) 21.11 Outflow-disk connection, outflow entrainment (H.B.) 28.11 Outflow-ISM interaction, outflow chemistry (H.B.) 05.12 Theory of outflow interactions: Instabilities, shocks (C.F.) 12.12 Outflows from massive star-forming regions (H.B.) 19.12 Radiation processes I (C.F.) 26.12 and 02.01 Christmas and New Years break 09.01 Radiation processes II (H.B.) 16.01 Observations of AGN jets (C.F.) 23.01 Some aspects of AGN jet theory (C.F.) 30.01 Summary, Outlook, Questions (H.B. & C.F.)
More Information and the current lecture files: http://www.mpia.de/homes/beuther/lecture_ws0809.html [email protected], [email protected]