Abel, Bryan, and Norman, (2002), Science, 295, 5552 density molecular cloud analog (200 K) shock 600 pc

The previous slide shows snapshots of a 3D hydrodynamical simulation of the formation of the first stars. Dark matter first condenses and then forms potential wells into which pre-galactic objects accumulate. The gas cools through vibration and rotational bands of the H-2 molecule. The bottom two rows show slices through the last simulation shown on the top row. The lower right panel shows a molecular cloud (T about 200 K) with a dense core a few hundred K hotter. This core is gravitationally bound. Within this core a dense knot of about 1 Msun has formed (yellow region of the red spot in the right panel of the second row). Recent calculations reported by Omukai and Palla (ApJ, 561, L55, (2001)) suggest that the fragments in the calculations of Abel et al will grow to about 300 solar masses before accretion is shut off by the stellar luminosity.

Baraffe, Heger, and Woosley, (2001), ApJ, 550, 890 nb. Even Z=0 stars burn hydrogen by the CNO cycle. T ~ 10 8 K

astroph

Heger and Woosley, (2002), ApJ, 567, 5332 At 133, without rotation, begin making massive back holes Helium coreNeutron excess

Yields of the dominant elements (left scale) and explosion energy (right scale) as a function of helium core mass. Helium cores of higher mass collapse to black holes. Those that make large abundances of 56 Ni will be exceptionally brilliant. oxygen Ni KE

Each supernova of this type injects about 50 solar masses into the “interstellar medium”. This is enough to provide a metallicity [Z] = -4 to 25 million solar masses of material, more than the proto- galactic fragments Abel et al. calculate.

Ordinarily a neutron excess is created during helium burning by but in a star that has no initial CNO there is no 14 N present in helium burning. Collapse then occurs before carbon or neon burning could create neutrons by other weak interactions. Consequently these stars have no r- or s-process and have trouble making elements with odd Z. During the collapse sufficient electron capture occurs, especially in the more massive models, to make odd-Z elements in the iron group.

Production factors for very massive stars ( solar mass helium cores corresponding to main sequence masses of solar masses) integrated over an IMF and compared with solar abundances. The integration assumed a Salpeter IMF with three different slopes (-.05, -1.0, -1.5). Zero r- and s-process. Heger & Woosley, (2002), ApJ, March 1.

Light curve of a 250 solar mass pair instability supernova at a red shift of 20. If 10(-6) of the baryons go into stars like this, one expects one explosion per square degree every 3 days might be visible per square degree. Wavelengths beyond the IGM Ly-alpha absorption (2.55 micons) are displayed as dotted lines. The first bump is shock break out. The long second one is the plateau.

Fryer, Woosley, and Heger (2001), ApJ, 550, solar mass star, 180 solar mass helium core. Makes black hole. Include rotation. Redshift ~ 20. Star initially forms a 50 Msun core with r about 1000 km. Neutrinos trapped. Possible rotational instability and gravity wave emission (EGW ~ M c 2 ). Later a 130 solar mass black hole accretes about 30 solar masses through a disk at a rate 1 – 10 solar masses per second. Up to erg might go into a jet.