musings about 30 dor
DESCRIPTION
Musings about 30 Dor. Hans Zinnecker DSI @ SOFIA Science Center NASA-Ames Research Center Moffett Field, CA (Univ. Stuttgart, Germany). Tarantula Nebula ([SII] image of the 30 Dor giant HII region taken by Walborn at CTIO-4m). - PowerPoint PPT PresentationTRANSCRIPT
Musings about 30 Dor
Hans Zinnecker
DSI @ SOFIA Science Center
NASA-Ames Research Center
Moffett Field, CA
(Univ. Stuttgart, Germany)
30 Dor, NGC 2070, R136
nomenclature (to avoid confusion)
30 Dor = giant HII region (200 pc)
N2070 = starburst cluster (20 pc)
R136 = central cluster (2 pc)
R136 core radius = 0.2 pc
cf. big Galactic cluster NGC 3603
1,2) initial conditions, initial location (past)
3,4) cluster IMF, SF history (num. simul.)
5, 6) feedback trigger on adjacent cloud,
two-stage starburst (2nd gen, present)
7, 8) close (“hard”) binaries, runaway stars
9,10) stellar + dynamical evolution (future)
10 question on 30 Dor
Introductory summary (1)
•largest star forming HII region in the Local Group
•closest resolved starburst cluster ("Rosetta Stone“)
•nearby (LMC at 50 kpc) details (e.g. IMF, SFH)
high-masses: ~ 100 O-stars
•stellar population:
low-masses: < 3MO pre-MS
•metallicity and age: Z ~ ZO/2.5 and 3±1.5 Myr
•origin: near LMC stellar bar, gas infall from SMC
•evolution: proto-globular cluster? staying bound?
Introductory summary (2)
stellar cluster ~ 105 MO
•mass total ionised gas 4.105 MO
mol. cloud (CO) ~ 105 MO
•central mass density ~ 105 MO/pc3
•total luminosity ~ 108 LO
•rate of ionising Lyc photons ~ 1052 s-1
•equivalent number O3-stars ~ 100 Ltot
Ekin (HII gas,tot) ~ 1052 ergs
•energetics Ekin (R136 shell) ~ 1051 ergs
Ekin provided by O-star winds, SNRs
kinematic study(slit positions)HII velocity dispersion~ 60km/s over 270pc
Chu & Kennicutt 1994
Violent star formationHII-region (v_rms>c_s)
Terlevich & Melnick 1981
from Zinnecker & Yorke 2007(Annual Reviews, Vol. 45)
SPH simulation of a turbulent100 pc 106 MO molecular cloud (Bonnell, Clark, & HZ, in prep.)
from Zinnecker & Yorke 2007(Annual Reviews, Vol. 45, 481)
SPH simulation of hierarchicalcluster formation (sub-clustersin the process of „wet“ merging)(Bonnell, Bate, & Vine 2003)
Maybe the N2070/R136 clusterformed by merging of subclusters(cf. WFC3 obs. Sabbi et al. 2012)
Reddening map of 30 Doradus calculated with an adaptive algorithm.The circles are centered in R136 with radii of 5", 15", 25", and 40". The reddening scale goes from AV=0 to AV=3.0, calculated assuming RV=3.05. North is up and east to the left; size is 133" or ~30 pc.
Selman et al. 1999
Selman et al. 1999
SFH of the cluster (3 bursts)
Spatial distribution of stars with M> 20 MO
as a function of age: green for youngest,yellow for middle-aged, and red for oldest
stars (approx. 1.5, 2.5, 5 Myr).WR stars are plotted using an asterisk.
1) definition "starburst" (SFR density or lum. density)
2) 30 Dor: initial conditions? (irrecognisable after MSF)
3) how to form 100 massive stars in such a small volume?
4) R136: truncated IMF? one-shot or multi-episode burst?
5) R136: initial mass segregation and stellar collisions?(likely conditions for progenitor of GRB or even IMBH?)
6) 30 Dor: a model for the origin of globular clusters?
QUESTIONS for discussion:
The far-infraredspectral energy distributionof the 30 Dor nebula;the curve is a 75 K blackbody fit.
Werner et al. 1978
( based on KAO observations)
High-flying aircraft --above 40,000 ft -- can observe most of the infrared universe
Airborne infrared telescopes can be more versatile -- and much less expensive -- than space infrared telescopes
NASA’s Kuiper Airborne Observatory (KAO) C-141 with a 36-inch telescope onboard, based at NASA-Ames near San Francisco, flew from 1975 - 1996
,
Werner et al. 1978Kennicutt 1984Melnick 1985Weigelt and Baier 1985Walborn and Blades 1987Kennicutt and Chu 1988Hyland et al. 1992Pehlemann et al. 1992de Marchi et al. 1993Parker 1993Parker and Germany 1993Chu and Kennicutt 1994Malumuth and Heap 1994Moffat et al. 1994Hunter et al. 1995Poglitsch et al. 1995Brandl etal. 1996Hunter et al. 1996Massey and Hunter 1998Rubio et al. 1998
References
Bosch et al. 1999Fukui et al. 1999Portegies Zwart et al. 1999Selman et al. 1999Zinnecker et al. 1999Grebel and Chu 2000Sirianni et al. 2000Bosch et al. 2001Massey et al. 2002P. Zwart & McMillan 2002Zinnecker et al. 2002Kim et al. 2003Maíz-Apellániz et al. 2004Maercker and Burton 2005Selman and Melnick 2005Koen 2006Townsley et al. 2006Zinnecker 2006Andersen et al. 2007Zinnecker and Yorke 2007