outflows and jets: theory and observations · outflows and jets: theory and observations winter...

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 beuther@mpia.de, fendt@mpia.de

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 beuther@mpia.de, fendt@mpia.de