John Bally Center for Astrophysics and Space Astronomy

Department of Astrophysical and Planetary Sciences

University of Colorado, Boulder

Recent Developments Recent Developments in Stellar and Planetary Systemin Stellar and Planetary System Formation Formation

Introduction Introduction • Star Formation: The fundamental cosmic (baryonic) process Determines cosmic fate of normal matter

Star Formation

Galaxy formation, evolution, IMF

Elements(He => U)

Clusters

black holes(AGN, stellar)

Light, K.E. of ISM

Planet formation

Conditions for life

Where planets also form

• Giant Molecular Cloud Core

• Gravitational Collapse & Fragmentation

• Rotation & Magnetic Fields

Raw material for star birth

Proto-stars, proto-binaries, proto-clusters

Accretion disks, jets, & outflows

Shrink size by 107; increase density by x 1021 !

Star FormationStar Formation

• PlanetsC. LadaMost may form in clusters!

Star-Formation:Star-Formation:• SF occurs in Giant Molecular Clouds (GMCs): Decay of turbulence +• Gravity + B Collapse => disks, jets => stars, planets• Fragmentation: Non-hierachical multiples: disintegration Dense (mostly unbound) clusters: < n*> ~ 103 - 105 pc -3 • 90% of stars born in OB associations: Multiple SN Superbubbles => inject short-lived isotopes

GMCs

OB *ssuperbubbles

Supershells / ringsgravity

20 - 50 Myr

Galactic 'ecology'

NGC 1333

IC 348

IRAS 03235+3004

M.Bate

SO

Spitzer IRAC

HH 46/47

HST 1997 - 1994

HH 46/47

HST 1997 - 1994

Irradiated jets in Car (Tr 14)

The Orion Star Forming Complex

Wei-Hao Wang

Infrared view of winter sky (10 - 120 m)

The Orion/Eridanus Bubble (H): d=180 to 500pc; l > 300 pc Orion OB1 Association: ~40 > 8 M stars: ~20 SN in 10 Myr

1a (8 - 12 Myr; d ~ 350 pc))

1b (3 -6 Myr; d ~ 420 pc)

1c (2 - 6 Myr; d ~ 420 pc)

1d (<2 Myr; d ~ 460 pc)

Ori (< 3 Myr)

Barnards's Loop Eridanus Loop

Orion B

Orion A

Orion Nebula

Orion MolecularClouds

13CO 2.6 mm

20

Orion belowthe Belt:

Horsehead Nebula

Orion Nebula

NGC 2024 (OB1 d)

Orionis (c)

NGC 1977

OriNGC1980: Source of Col + AE Aur ; V ~ 150 km/s runaways, 2.6 Myr ago

NGC 1981

Ori OB1c

Ori OB1d

NKLTrapezium

OMC1-S

(L = 105 Lo

t << 105 yr)

(L = 104 Lo ,

t < 105 yr)

(L = 105 Lo

t < 105 yr )

OMC 1 Outflow

t = 3,000 yr)

Orion NebulaOrion Nebula

Trapezium clusterTrapezium cluster

Proper motions:Van Altena et al. 88

Vesc ~ 6 km s-1

2.6

1.8

5 2.5

OrionBN/KLH2

NICFPSAPO 3.5 mFirst light21 Nov 04

0.5 – 2.2 m

104 AU

11.7 m

Gemini STReCS

104 AU

OMC1OMC1H2 fingers

High-velocity stars: I , BN , n (Gomez et al. 2005)

BN: V~ 30 km s-1

I: ~ 13 km s-1

n: ~ 20 km s-1

d253-535 in M43

UV photo-ablation of disks & planet formation:UV photo-ablation of disks & planet formation:

Orion Nebula: Disks seen in silhouette

HST 16

HST 10

HST 17

Irradiated proto-planetary disks:

Anatomy of a planetary systemforming in an OB association

Disk mass-loss:Disk mass-loss:UV Radiation => heatimg = > Mass – loss ~ 1 Myr

r > GM / c2

~ 40 AU for Soft UV (91 < < 200 nm)

~ 5 AU for ionizing UV ( < 91 nm) (for Solar mass) Self-irradiation by central star vs. External irradiation by nearby massive star:

Lself(UV) / 4 d*2 = Lexternal(UV) / 4 dOB

2

Lexternal(UV) ~ 1049 photons / sec Lself(UV) ~ 1040 - 1043 photons / sec

Impacts of the environment: Impacts of the environment: Life of a massive star ~ 3 to 40 Myr ~ planet formation time-scale• Clustering, multiplicity: - Close-encounters - Truncate, shock-heat disks• UV radiation: - External + Self => Mass-lost in ~ few Myr

UV dose: 1042 – 1045 t ( sec-1)

Main-sequence star (3 – 30 Myr) Blue-supergiant (< 106 years) Supernova (1 year)• Massive star winds, Supernovae: - Inject short-lived isotopes: 26Al, 60Fe

UV => Fast Growth of Planetesimals:UV => Fast Growth of Planetesimals:

Grain growth => Solids settle to mid-planeUV => Remove dust depleted gas => High metallicity in mid-planeGravity => Instability => 1 - 100 km planetesimals

- Fast Formation of 1 to 100 km planetesimals

Growing grains: Orion 114-426 (Throop et al. 2001)

Oldest meteorites: (CAIs: 4,567.6 Myr old = 0 )Chondrules: +2 to 4 Myr

26Al => 26 Mg (t1/2 ~ 0.7 Myr) 60Fe => stable elements (t1/2 ~ 1.5 Myr) => Solar System formed in Orion-like OB association SN within few pc, few Myr of forming Solar System

Supernovae:Supernovae:

ConclusionsConclusions• Most stars form in Orion-like regions - Sibling star interactions - Jets => halt star formation• Proto-planetary disks processed by UV - Gas lost in few x 106 years - Grain growth + sedimantation + UV => Prompt planetesimal formation• Massive Stars: - Mutual interactions => high velocity stars (BN) => explosive outflows - HII regions => halt star formation - Supernavae: => Inject 60Fe, 26Al, …

The End