star formation: the good, the bad, and the ugly

Star Formation

GOODBAD

UGLY

TH

E

TH

E

AN

D T

HE

Eli Bressert@astrobiased

GOODTH

E

Molecular clouds

Cores

Young stellar objects

Disks & planets

Molecular cloud

cores

Stars

Gas

1

2 3

123

age < ? million years

10 pc < scale < 500 pc

age < 0.5 million years

scale < 10000 AU

age < 10 million years

scale < 500 AU

PLANET!!!

[Not to scale]

BAD TH

E

Different modes of star formation?

Massive stars only form in massive clusters?

Different modes of star formation?

Distributed

Clustered

[Simulated]

�⇤ = j�1(�r2j )

Casertano & Hut 1985

5th closest

HistogramClusteredDistributed

Clustered

Distributed

Cumulative

Cumulative

Bressert et al. (2010)

Carpenter (2000)Gutermuth et al. (2009)Lada & Lada (2003)Jørgensen et al. (2008)Megeath et al. (in prep.)

Different modes of star formation?

Unlikely

Can massive stars form in isolation?

Why is it important?

12

initial mass function

star formation models

10 x

P( ) P( )=

50 M☉ 50 M☉

P( ) P( )=Stochastic

SortedP( ) P( )=

How can we test it ... and where?

Weidner et al. 2010

log(Mcluster / Msun)

log

(Mst

ar /

Msu

n)

Weidner et al. (2010)

Isolate

d!!!

100 pc

Credit: ESO/VISTA Magellanic Cloud survey

Tarantula Nebula

Line

of sig

ht Plane of sky

NewMolecular filaments (MF)

Bressert et al. (2012)

ESO/M.-R. Cioni/VISTA Magellanic Cloud survey

PI: Chris Evanshttp://arxiv.org/abs/1103.5386

800 OB Stars

300 O-stars

180 Single O-stars

VFTS

Likely

Can massive stars form in isolation?

UGLYAN

D T

HE

How do young massive clusters form?

What do the progenitors look like?

How do we find

them?

Credit: ESO/VISTA Magellanic Cloud survey

100 pc

R1361-2 Myr

>104 M⊙

SFE > 30 %

15 pc

Credit: ESO/S. Guisard

Ophiuchus~2 Myr

~102 M⊙

SFE < 10 %

Meanwhile, back in the Galactic Centre ...

The BrickLongmore et al. (2012)

Credit: NASA/JPL-Caltech/GLIMPSE Team

PI: Jill Rathborne

ALMACycle 0

Prediction

Bressert et al. (2012)Ginsburg et al. (2012)

All YMC progenitors in MW are detectable with current surveys1Like HST on globular clusters, ALMA will shed light on extragalactic YMC progenitors2

Longmore et al. (2013)

Credit: NASA/JPL-Caltech/GLIMPSE Team

The Brick

bricklets

Not much

How much do we know about YMC formation?

?