Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Disks around High-Mass (Proto-)Stars  From Low to High-Mass Stars  The Quest for Disks around Intermediate and High Mass Stars  High-mass Protostellar “Disks”  The Role of Disks in the Formation of Massive Stars Leonardo Testi (INAF--Osservatorio Astrofisico di Arcetri)

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 From Low- to High-Mass Stars Log 10 (N Ly ) T eff B0 A0 B3 A0 Palla & Stahler <M  /M ʘ <15

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 From Low- to High-Mass Stars  Transition from “quiet” low-mass and “violent” high-mass star- formation M17: O-stars, cluster and HII region NGC2023: B1 star, PDR HH 111: low-mass disk-jet system (Reipurth et al 1999) HD100546: B9 star with disk (Augereau et al 2001)

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Clustering properties  Clear dependence of the clusters richness with the spectral type of the Herbig Ae/Be star (the most luminous - massive - member)  No clusters and no evidence for dynamical dissipation around HAe stars (as expected)  Increase in cluster density with Sp. type Testi et al It is tempting to speculate that there is a physical connection between clusters and massive stars (and their formation mechanism). Available data is insufficient to claim this conclusion.

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 HAeBe Circumstellar Material  Envelopes are dispersed on a timescale of a few Myrs  The evolution is more rapid around early type stars Fuente et al. 1998/2002 Late-type Early- type Low Resolution Observations

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 The disks/envelopes debate  Extended emission detected at 50/100  m (KAO)  Models require Disk+Envelope Di Francesco et al. 1994/1998 Natta et al AB Aur Elias 1 R CrA PV Cep LkH  198 R Mon LkH  198 LkH  234 HD BD+40 MWC297 CoD – 40 o MWC 137 MWC 1080 V645 Cyg

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 The AB Aur Circumstellar Disk  Detection at mm wavelengths confirm that the spiral structure seen in scattered light correspond to a density contrast in the disk OVRO 2.7mm (Corder et al. 2005) Also confirmed by PdBI and SMA Observations (Pietu et al. 2005; Lin et al. 2005)

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 The Case of HD  Disk resolved at 7mm (VLA) and at 2.7 and 1.2mm (PdBI)  R~300 AU; Σ(r)~r -p ; p~1.5  β~0.8  Next step: dust properties as a function of radius P=1.0 P= mm 7 mmα 1-7mm

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Disks around HBe Systems?  Very little evidence for disks around HBe stars  mm-interferometers confirm KAO-FIR observations  Most of the circumstellar material is in envelopes Compilation by Natta et al Late-type Early-type Fuente et al. 1998/2002

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 PdBI+VLA Search for HBe Disks  3.6, 1.3 & 0.7 cm & 1.3mm  Dusty disks are detected in 2 out of four objects  Dusty disks around HBe stars are less massive and have short lifetimes compared with lower mass systems Fuente et al. 2003

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Young Massive (Proto-)Stars  Hot Molecular Cores  A young massive star will still be depply embedded in dense gas and will significantly start to heat it while still accreting.

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 IRAS  Isolated Hot Molecular Core relatively low mass and low luminosity OVRO: CO(1-0) Palomar: H 2 NOAO: H , [SII] (Shepherd et al. 2000) PdB: HCO + (1-0) NOT/ARNICA: H 2 VLA: 3.6cm, H 2 O (Cesaroni et al ) Hot Molecular Core (CH 3 CN, CH 3 OH, C 34 S, NH 3 …)

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 IRAS Cesaroni et al. (2005) Moscadelli et al. (2005) M * =7 M O Keplerian rotation M * > M HMC

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Disks and High-Mass (Proto)stars  Very common to find velocity gradients in HMCs  These gradients are usually perpendicular to outflow axis  Disks? Cesaroni et al. Beltran et al.

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Beltran et al. (2005); Hofner et al. (in prep.) HC HII or wind HMC CH 3 CN(12-11)

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Beltran et al. (2005); Hofner et al. (in prep.) NH 3 red-shiftedNH 3 blue-shiftedNH 3 bulk CH 3 CN(12-11)

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Cesaroni et al. (2003)

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Cesaroni et al. (2003) Codella et al. (1997) Furuya et al. (2002) T=30 K T=120 K

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Codella et al. (1997) Furuya et al. (2002) O M O

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Beltran et al. (2004,2005) Furuya et al. (2002)

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Beltran et al. (2004,2005) Furuya et al. (2002) Forster & Caswell (1989) Moscadelli et al. (in prep.) M dyn = 19 M O M dyn = 55 M O

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 A possible scenario for high-mass SF Unstable clump: t ff =10 5 yr Inside-out collapse: dM accr /dt=M clump /t ff =10 -2 M O /yr Rotation of core with rotation period=10 5 yr infalling Clump n  R -3/2 n  R -2 rotating Core

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 A possible scenario for high-mass SF Unstable clump: t ff =10 5 yr Inside-out collapse: dM accr /dt=M clump /t ff =10 -2 M O /yr Rotation of core with rotation period=10 5 yr Fragmentation over R centrifugal =R HMC /5=0.01 pc infalling Clump n  R -3/2 n  R -2 rotating Core rotating disks

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 A possible scenario for high-mass SF Unstable clump: t ff =10 5 yr Inside-out collapse: dM accr /dt=M clump /t ff =10 -2 M O /yr Rotation of core with rotation period=10 5 yr Fragmentation over R centrifugal =R HMC /5=0.01 pc Formation of HMC infalling Clump n  R -3/2 n  R -2 rotating HMC circumstellar disks

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Contracting Clumps  Best examples: G29.96, G34.26 OVRO: HCO+(1-0) SiO(2-1,v=0) (Maxia et al. 2001)

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 Contracting Clumps  Best examples: G29.96, G34.26 G OVRO: C 33 S(2-1) C 34 S(2-1) CH 3 OH(2-1) (Testi et al. 2001)

Leonardo Testi: (Sub)Millimeter Observations of Disks Around High-Mass Proto-Stars, SMA, Cambridge 14 Jun 2005 (sub)mm-  Disks need:  High angular resolution  High surface brghtness sensitivity  Wide waveband coverage  Current facilities  VLA  PdBI/NMA  SMA  Approaching the horizon  CARMA  eVLA  ALMA Disk structure: Dust and Gas; Disk Evolution; Disk Chemistry; Large Samples