Second-Generation Star Formation in Primordial Supernova Remnants

Second-Generation Star Formation in Primordial Supernova Remnants

Katharina M. J. Wollenberg

Universität Heidelberg

Ke-Jung (Ken) Chen, Daniel J. Whalen, Simon C. O. Glover, Ralf S. Klessen

First stars, galaxies, and black holes: Now and Then

Groningen, The Netherlands - June 16, 2015

Triggered Star Formation in the Primordial Universe

QUESTION: Do second generation stars promptly form in the debris of a

photoevaporated halo?

METHOD: 2-step Process

1. ZEUS-MP: Photoevaporation of a primordial halo by a nearby Pop III star during the lifetime of the star

2. CASTRO AMR: After the SN explosion metals

wash over the photoevaporated halo

ZEUS-MP

• multifrequency radiation hydrodynamics code (Whalen & Norman 2006/2008 a,b)

• self-consistently solves hydrodynamics, UV radiation transport and

primordial gas chemistry: H, H⁺, He , He⁺ , He²⁺ , H , H₂⁺ , H₂ , e

• cooling and heating due to:

– collisional ionization and excitation of H and He – recombinations of H and He

– inverse Compton scattering from CMB – bremsstrahlung emission

– H₂ cooling

• discretized blackbody emission rates:

40 uniform bins from 0.755 eV to 13.6 eV 80 logarithmic bins from 13.6 eV to 90 eV

• H² photodissociation via self-shielding function (Draine & Bertoldi (1996))

Model Grid

• Halo 1: 6.9 ⇥ 10

M Halo 2: 1.2 ⇥ 10

M Halo 3: 2.1 ⇥ 10

M

• Pop III stars:

25 M at 250 pc 200 M at 500 pc

• 2D cylindrical grid (r, z) with halo centred on the z-axis

• 1000 zones in z,

500 zones in r

• 1024 x 2048 cartesian grid

• SN ejecta initialized by a time dependent pulse of plane-wave inflow

• peak velocity 100 km/s

CASTRO AMR CODE

Image: Ken Chen

Core will still

collapse and form Pop III stars

2nd generation

star formation,

if present, will

create arc of

metal enriched

stars around

the halo

Video: Ken Chen

Video: Ken Chen

Video: Ken Chen

Video: Ken Chen

Stay Tuned!

PROSPECTS: Implementation of

• fine-structure cooling by metals

• dust formation and destruction

• implementation of 3D simulation

Thank you!