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 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 10 7 ; increase density by x ! Star Formation Star Formation Planets C. Lada Most may form in clusters!

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: ~ pc -3 90% of stars born in OB associations: Multiple SN Superbubbles => inject short-lived isotopes GMCs OB *s superbubbles Supershells / ringsgravity Myr      Galactic 'ecology'

NGC 1333 IC 348 IRAS

M.Bate

 S  O 

Spitzer IRAC

HH 46/47 HST

HH 46/47 HST

Irradiated jets in  Car (Tr 14)

The Orion Star Forming Complex Wei-Hao Wang

Infrared view of winter sky (  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 ( 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 Molecular Clouds 13 CO 2.6 mm

20

Orion below the Belt: Horsehead Nebula Orion Nebula NGC 2024 (OB1 d)  Orionis (  c) NGC 1977  Ori NGC1980: Source of  Col + AE Aur ; V ~ 150 km/s runaways, 2.6 Myr ago NGC 1981 Ori OB1c Ori OB1d

 NKL  Trapezium  OMC1-S (L = 10 5 L o t << 10 5 yr) (L = 10 4 L o, t < 10 5 yr) (L = 10 5 L o t < 10 5 yr ) OMC 1 Outflow   t = 3,000 yr) Orion Nebula

Trapezium cluster Proper motions: Van Altena et al. 88 V esc ~ 6 km s

Orion BN/KL H 2 NICFPS APO 3.5 m First light 21 Nov 04

0.5 – 2.2  m 10 4 AU

11.7  m Gemini S TReCS 10 4 AU

OMC1 H 2 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

d in M43 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 system forming in an OB association

Disk mass-loss: UV Radiation => heatimg = > Mass – loss  ~ 1 Myr r > GM / c 2 ~ 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: L self (UV) / 4  d * 2 = L external (UV) / 4  d OB 2 L external (UV) ~ photons / sec L self (UV) ~ photons / sec

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: –  t (  sec -1 ) Main-sequence star (3 – 30 Myr) Blue-supergiant (< 10 6 years) Supernova (1 year) Massive star winds, Supernovae: - Inject short-lived isotopes: 26 Al, 60 Fe

UV => Fast Growth of Planetesimals: Grain growth => Solids settle to mid-plane UV => Remove dust depleted gas => High metallicity in mid-plane Gravity => Instability => km planetesimals - Fast Formation of 1 to 100 km planetesimals

Growing grains : Orion (Throop et al. 2001)

Oldest meteorites: (CAIs: 4,567.6 Myr old = 0 ) Chondrules: +2 to 4 Myr 26 Al => 26 Mg (t 1/2 ~ 0.7 Myr) 60 Fe => stable elements (t 1/2 ~ 1.5 Myr) => Solar System formed in Orion-like OB association SN within few pc, few Myr of forming Solar System Supernovae: Supernovae:

Conclusions Conclusions 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 10 6 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 60 Fe, 26 Al, …

The End