OB Spectral and Spatial Morphology from Carina to the Antennae

OB Spectral and Spatial Morphologyfrom Carina to the Antennae

Nolan R. Walborn

Space Telescope Science Institute

HotSci

STScI

August 17, 2011

Walborn Diagram

OpticalO MainSequence

N IV/IIIHe II/I

UV O Main Sequence (No Si IV)

UV OB Main Sequence (No Si IV)

OpticalEarly OSupergiantSequence

N IV/III

OpticalOBSupergiantSequence

Si IV/III/II

UV OSupergiantSequence

Si IV!

UV BSupergiantSequence

Si IV!

FUV O Supergiant Sequence (O VI, C III)

Optical O Luminosity Sequence (He II λ4686, N III λ4640)

UV O Luminosity Sequence (Si IV! 45 eV)

FUV O Luminosity Sequence (S IV 47 eV, C III 48 eV, P V 65 eV but low abundance!)

X-Ray OBSupergiantSequence

Si XIV/XIIIMg XII/XINe X/IXO VIII/VII

X-Ray OBMainSequence

Si XIV/XIIIMg XII/XINe X/IXO VIII/VII

New Of?p StarsGOSSSJ. Maiz Apellaniz et al.ApJS 193, 24 (2011)

Ofc SpectraGOSSS

ONn SpectraGOSSS

VFTSC. Evans et al., A&A530, A108(2011)

All SingleO Stars

Vz Stars

J. Maiz Apellanizin prep.

Vn/nn/nnn Stars(red)

H. Sana

VISTA Blue J

SpitzerGreen 4.5 Red 8 micron

R. Barba et alin prep.

N11LMC

NGC 5471 M101

Region G has only a single dominant central cluster (brightest in the Antennae), but again shows evidence for some weak triggering.

The mass in the intermediate age clusters is only about 5 % of the mass of the central cluster, hence the triggered star formation is a relatively minor effect.

Note the beautiful H_alpha shells, which have expanded unimpeded to the left, but have run into material and appear to have formed clusters in other directions

Region G

B. Whitmoreet al. (2010)

We find a smooth gradient in the ages!

In addition, the supershell is centered on the old cluster, and the young clusters are located where the shell intersects the dust lane !

The young clusters have a total mass of 4 E6 Msolar, 5 times more than the cluster that appears to have triggered their formation.

Triggering is not always weak !

Region B

Antennae

Spitzer HST/ACS

<1 Myr

1-2 Myr

3-4 Myr

4-5 Myr

7-9 Myr

B

S

G