The Origin of Stars

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The Origin of Stars
Where do stars come from? Born or bred? Nature or
nurture?
How are they conceived?
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Talk outline
From core to cloud to complex.

• The Revolution
• Simple Systems single outflows/cores
• Complex Systems
• The ? Ophiuchus project
• NIR observations and results
• MM observations and results
• Global picture

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The Star Formation Revolution

• Short gestation - turbulence ephemeral
  clouds
• The Birth abrupt Class 0 high
  accretion
• Powerful jets
  high extraction
• Form in clusters in giant clouds spatial
  distribution
• Brown dwarfs and planets mass
  distribution
• Primordial stars early re-ionisation, z20
  stars.

Turbulence, Gravity, Feedback, Regulation,
Interaction, Triggering COMPLEX SYSTEM
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Signs of youth HH240(OConnell, Smith, Davis,
Hodapp, Khanzadyan, Ray 2004)
Low-mass star formation shock sculpted

• Microsystems analyse components
• Purpose understand ordered structure
• Determined by driver or environment?
• L1634 (Orion), IRAS 05173-0555,
• late Class 0, 2-3 Msun
• Outflow 0.84 pc.
• NIR UKIRT images, Echelle spec ...

HH 211 (OConnell, Smith, Froebrich, Davis,
Eisloeffel)

• IC348 cloud complex, Perseus
• Early Class 0, 0.1 Msun, 4.5 Lsun
• Small outflow 0.16 pc (350 pc)

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The signatures of protostars in ? Ophiuchus

• An unbiased search for the signatures of
  protostars in the ? Ophiuchi
• Molecular Cloud

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Collaboration between

• Roland Gredel Tigran Khanzadyan (MPIA)
• Thomas Stanke (MPIfR, Bonn/Hawaii)
• Michael D. Smith (Armagh Observatory)

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Why rho Oph?

• Historically ?Oph was thought to be an example of
  spontaneous star formation
• Its the place where new theories of Mol.
  Clouds were, is and will be tested.
• Contains first detected Class 0 source
  (VLA1623A Andre 1990).
• First statistics for protostars dependence
  between number of protostars (say Class 0) with
  the average time spend in that stage (e.g. NClass
  0 tClass 0.)

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Useful facts L1688

• First detection of the Great Nebulous Region in
  1893 by Barnard
• Contains a number of dark clouds (Lynds 1962)
• Estimated distance 130pc (Rebull et al. 2004)
• Estimated mass 104 M? in CO (de Geus et al.
  1990)
• Star Formation is triggered by ionisation fronts
  and winds from the Upper Scorpius-Centaurus OB
  association located in the West (e.g. Loren 1989)
• Most active part is L1688, with gt 50 stars per
  pc2 at different evolutionary stages (15
  citations)
• In this region (west part of L1688) visual
  extinction is over 50 - 100 magnitudes (Vrba et
  al. 1975, Wiliking Lada 1983)

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Where is it on the sky?
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Coverage.
1 degree
NIR coverage
MM coverage
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Previously...

• Outflow studies
• 12 CO outflows have been recorded (Terebey et
  al.1989 Andre et al.1990 Dent et al.1995 )
• Many HH objects have been discovered at the
  perimeter of the cloud (e.g. Phelps Barsony
  2004)
• H2 (2.12µm) only small places, mainly covering
  not connected portions of the cloud (Davis
  Eisloeffel 1995 Dent et al.1995 Davis et al.
  1999 Grosso et al. 2001) until ..
• Gomez et al. 2003 presented results from wider
  coverage (480 arcmin2) in H2

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Previously.

• MM studies
• 1.3mm survey by Motte et al. 1998
• 62 starless clumps and 41 circumstellar
  structures
• HPBW 11
• 0.85 mm survey by Johnstone et al. 2000
• 55 clumps were identified
• HPBW 14
• Covered area 700 arcmin2

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Observations
NIR
MMS

• SOFI _at_ NTT Aug.01
• H2 1-0 S(1)_at_ 2.12µm Ks
• 12.62 arcmin fields
• 7 fields with 10min integration
• OPrime _at_ 3.5m CAHA Aug.03
• H2 1-0 S(1)_at_ 2.12µm Ks
• 15.3 arcmin fields
• 3 fields with 10min integration
• Overall coverage is1500 arcmin2
• (480 arcmin2 by Gomez et al.03)

• SIMBA _at_ SEST Jul.02
• 1.2mm with HPBW24
• 1200 x 800 map sizes
• 78 maps in total
• Overall coverage is 4600 arcmin2
• (700 arcmin2 by Johnstone et al.00)

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Searching for H2 tracks

• We have more than 35 x 35 field coverage
• No objects were found in some fields.
• F01 and F02 down to detection limit
• F06 and F07 due to high noise ? AM gt 2
• In 6 fields we identified
• 74 individual knots, separated in 20 groups of
  knots from f03-01 to f10-04
• 11 - 13 distinguishable outflows
• 9 outflow sources were possible to identify

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MM face of ?Oph before and after face lifting
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The MM clumps and cores

• We surveyed more than 1 deg2 field
• There is no structural differences with earlier
  studies in the common survey areas
• Apart from already known global clumps A to G, we
  detect a new clump containing several compact
  sources
• MM Sources
• Total of 151 sources have been detect and
  measured
• 118 have no detected stellar objects
• We identify a core, MMS126, which appears to
  harbour a new possible Class 0 protostar.

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HH obj
NIR MM
2
3
H2 obj
1
10
MM cores
4
11
6
8
5
7
9
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Summary

• We identified just 11 H2 outflows
• From spatial distribution and bow shock shapes we
  suggest driving sources, which are mainly deep
  embedded in dense cores.
• A very young outflow emerges from a newly
  discovered Class 0 source (MMS 126). Others are
  driven from well known Class I sources (e.g.
  YLW15, YLW16, YLW31 )
• Flow directions are generally NE-SW,
  perpendicular to the elongation directions of the
  cloud filaments.
• The extent of outflows are related to either the
  widths of the cloud filaments or to the
  separation between filaments.
• The estimated jet power needed to continously
  drive and excite the detected portions of the
  shocked H2 outflows 0.02 0.2 L?, which is
  10-6 to 10-7 M?/year for outflow rate (10 of
  accretion rate)

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The MM cores mass distribution
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The MM cores spatial distribution
2-point correlation function slope - 0.63 no
break
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Further implications

• A deeper survey?
• Discover more weak knots in each flow
• Detect outflows from Class 2 sources.
• Do we have complete picture?
• Having the same number of H2 and CO outflows is a
  good sign of almost completeness.
• Outflow number is also consistent with the number
  of Class 0 and Class I sources in the vicinity of
  our survey. So we detect almost all powerful
  flows (from Class 0 and 1).
• If we had detected more flows, it would imply
  higher rates of accretion (gt 10-6 M?/year) for
  Class 2 sources, which would have been
  problematic for models.

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New tasks?

• Wider coverage in H2 1-0 S(1) _at_ 2.12µm
• Match our MM coverage for completeness
• Study proper motions
• Narrower coverage of Class 0 source/outflow
• CO survey of the same area for outflows
• Other molecular lines like 13CO, CS, HCO N2H
  (MOPRA)

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Summary

• Complex systems possess analysible components
• CS? Non-linear, nested, open, range of forces
• feedback emergence!
• Emergence of spatial and mass distributions of
  stars
• Problem origin of starless cores?
• Or, are these not pre-protostellar cores?

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Supercomputer Simulations (Rosen Smith
2004 Smith Rosen 2004)

• ZEUS-3D FORGE chemistry cooling
• Heavy ballistic molecular jet, 100 km/s
• Uniform molecular cloud
• Injection shear, pulsation and precession
• Size 0.04 pc Time scale 500 years
• Published evolving mass ejection rate

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400yr Precession
H2 2.12 mm, NIR
CO 2-1 230 GHz
Atomic optical
H2 8.0 mm, Spitzer
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400yr Precession pulsed
CO 2-1 230 GHz
H2 2.12 mm, NIR
H2 2.12, mm, re-scaled
Atomic optical
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Spitzer Infrared Outflows (Smith Rosen 2004b)

• 4 infrared bands, 3 - 8 microns
• H2 flows predictions

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Reduction Analysis - MM

• Data Reduction MOPSI (Robert Zylka) following
  standard bolometer data reduction principles (ask
  Th. Stanke for details).
• Source finding Detailed modelling of the
  brightness distribution using Gaussian sources.
  In some cases, more than one Gaussian component
  was assumed in order to properly reproduce the
  shape of the sources.