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