The Formation of the First Stars. II. Radiative Feedback Processes and Implications for the Initial Mass Function

By C. McKee, Jonathan C. Tan. 2007

203 citations recorded by the source corpus.

We consider the radiative feedback processes that operate during the formation of the first stars. (1) Photodissociation of H2 in the local dark matter minihalo occurs early in the growth of the protostar but does not affect subsequent accretion. (2) Lyα radiation pressure acting at the boundary of the H II region that the protostar creates in the accreting envelope reverses infall in the polar directions when the star reaches ~20-30 M☉ but cannot prevent infall from other directions. (3) Expansion of the H II region beyond the gravitational escape radius for ionized gas occurs at masses ~50-100 M☉. However, accretion from the equatorial regions can continue since the neutral accretion disk shields a substantial fraction of the accretion envelope from direct ionizing flux. (4) At higher stellar masses, ~140 M☉ in the fiducial case, photoevaporation-driven mass loss from the disk, together with declining accretion rates, halts the increase in the protostellar mass. We identify this process as the mechanism that determines the mass of Population III.1 stars (i.e., stars with primordial composition that have not been affected by prior star formation). The initial mass function of these stars is set by the distribution of entropy and angular momentum. The Appendix gives approximate solutions to a number of problems relevant to the formation of the first stars: the effect of Rayleigh scattering on line profiles in media of very large optical depth, the intensity of Lyα radiation in very opaque media, radiative acceleration in terms of the gradient of a modified radiation pressure, the flux of radiation in a shell with an arbitrary distribution of opacity, and the vertical structure of an accretion disk supported by gas pressure with constant opacity.

Subfields: Astronomy and Astrophysics, Education, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b94c7bc024b02fa04d9d57ad3769334cccb8a379

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Citations in the corpus

ONE HUNDRED FIRST STARS: PROTOSTELLAR EVOLUTION AND THE FINAL MASSES (2013, background): “McKee & Tan (2008) adopt the rotational degree of the cloud fKepler as a key parameter which determines the final stellar mass in their semi-analytic model.”
The First Stars (2012, methodology): “McKee & Tan (2008) also show that the accretion disk can survive for a considerable period after the HII region has broken out, and that the protostar will stop accreting from the disk only once the rate at which gas is lost from the disk by photoevaporation exceeds the rate at which fresh gas is…”
Building up the Population III initial mass function from cosmological initial conditions (2016, methodology): “From the expressions in the above-mentioned studies, we estimate Nscat ≃ 100 for the ionized region and one to two orders of magnitude higher in a similarly sized neutral region (e.g. Bithell 1990; Haehnelt 1995; McKee & Tan 2008).”
The first stars: formation of binaries and small multiple systems (2009, background): “As demonstrated by McKee & Tan (2008), the disk structure will mitigate the impact of protostellar feedback.”
FORMATION OF MASSIVE PRIMORDIAL STARS: INTERMITTENT UV FEEDBACK WITH EPISODIC MASS ACCRETION (2015, background): “…FUV emissivities are calculated assuming a black-body spectrum SEUV = 4πR 2 ∗ ∫ ∞ 13.6 eV πB(Teff) hν dν, (21) SFUV = 4πR 2 ∗ ∫ 13.6 eV 11.2 eV πB(Teff) hν dν, (22) (McKee & Tan 2008, HS11), where the effective temperature is given by Teff = ( L∗ 4πR2∗σ )1/4 , (23) where σ is Stefan-Boltzmann…”
Primordial star formation under the influence of far ultraviolet radiation: 1540 cosmological haloes and the stellar mass distribution (2015, background): “9 in McKee & Tan 2008) and our results (Fig.”
Formation of supermassive black holes (2010, background): “The characteristic final mass at the end of the accretion process can be much less than the initial clump mass as feedback effects can act, strongly reducing the ability of the core to accrete material (McKee and Tan, 2008).”
SIMULATIONS ON A MOVING MESH: THE CLUSTERED FORMATION OF POPULATION III PROTOSTARS (2011, background): “Finally, it is important to point out that the heating may be much more severe once the first protostar has accreted of order 10M⊙ and begins to emit ionizing radiation (Tan & McKee 2004; McKee & Tan 2008).”
Production of dust by massive stars at high redshift (2011, background): “The very first stars (Pop III.1) formed in isolation and are expected to have been relativelyrare, only about 10% by mass of all generations of Pop III stars (e.g., Greif and Bromm, 2006; McKee and Tan, 2008).”
Supermassive black hole formation by direct collapse: keeping protogalactic gas H2 free in dark matter haloes with virial temperatures Tvir > rsim 104 K (2009, background): “See McKee & Tan (2008) for a more detailed discussion in the context of first star formation in minihalos.”
The First Stars: Mass Growth Under Protostellar Feedback (2011, methodology): “Thus, while our results underestimate the effect of shielding, it still highlights how nonaxisymmetry will enhance the effects of radiative feedback, and the true physical case likely lies somewhere in between our ‘with-feedback’ case and the prediction of McKee & Tan (2008).”
FORMATION OF PRIMORDIAL SUPERMASSIVE STARS BY RAPID MASS ACCRETION (2013, background): “In disk geometries, however, a bipolar Hii region should emerge and strong UV feedback could limit mass accretion much earlier, as expected in the standard cases of primordial star formation (e.g., McKee & Tan 2008; Hosokawa et al. 2011b; Stacy et al. 2012; Susa 2013).”
What drives the growth of black holes (2011, background): “…studies have challenged the idea that the first stars are very massive, due to either fragmentation or feedback effects (e.g., Glover et al., 2008; McKee & Tan, 2008; Turk et al., 2009; Trenti & Stiavelli, 2009; Stacy et al., 2010; Greif et al., 2011), casting some doubt on the the role of…”
Can Supermassive Black Holes Form in Metal-enriched High-Redshift Protogalaxies? (2008, background): “During the accretion phase, radiative and mechanical feedback effects might become important and eventually halt the accretion at some phase (e.g., Omukai & Palla 2003; McKee & Tan 2008).”
Possible indirect confirmation of the existence of Pop III massive stars by gravitational wave (2014, background): “First of all, Pop III stars are more massive than Pop I stars (McKee & Tan 2008; Hosokawa et al. 2011, 2012; Stacy, Greif & Bromm 2012) with mass 10–100 M so that Pop III star binaries probably evolve into BH–BHs.”