The r-Process in Neutrino-driven Winds from Nascent, “Compact” Neutron Stars of Core-Collapse Supernovae

By S. Wanajo, Toshitaka Kajino, G. Mathews, K. Otsuki. 2001

153 citations recorded by the source corpus.

We present calculations of r-process nucleosynthesis in neutrino-driven winds from the nascent neutron stars of core-collapse supernovae. A full dynamical reaction network for both the α-rich freezeout and the subsequent r-process is employed. The physical properties of the neutrino-heated ejecta are deduced from a general relativistic model in which spherical symmetry and steady flow are assumed. Our results suggest that proto-neutron stars with a large compaction ratio provide the most robust physical conditions for the r-process. The third peak of the r-process is well reproduced in the winds from these "compact" proto-neutron stars even for a moderate entropy, ~ 100NAk-200NAk, and a neutrino luminosity as high as ~1052 ergs s-1. This is due to the short dynamical timescale of material in the wind. As a result, the overproduction of nuclei with A ≲ 120 is diminished (although some overproduction of nuclei with A ≈ 90 is still evident). The abundances of the r-process elements per event is significantly higher than in previous studies. The total integrated nucleosynthesis yields are in good agreement with the solar r-process abundance pattern. Our results have confirmed that the neutrino-driven wind scenario is still a promising site in which to form the solar r-process abundances. However, our best results seem to imply both a rather soft neutron-star equation of state and a massive proto-neutron star that is difficult to achieve with standard core-collapse models. We propose that the most favorable conditions perhaps require that a massive supernova progenitor forms a massive proto-neutron star by accretion after a failed initial neutrino burst.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/9e31d993f1c509193f082a80b2b73d76f8f53130

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Citations in the corpus

Nuclear weak-interaction processes in stars (2002, background): “These authors also observe that relativistic effects as well as nuclear reaction paths through neutron-rich light elements might be helpful for a successful r-process (Otsuki et al., 2000; Terasawa et al., 2001a,b; Wanajo et al., 2001).”
Europium production: neutron star mergers versus core-collapse supernovae (2013, background): “…two possible sites have been suggested for the production of Eu in stars: SNeII of either low (8– 10 M⊙) or high mass (> 20 M⊙; Cowan et al. 1991; Woosley et al. 1994; Wanajo et al. 2001) and CBM (Lattimer & Schramm 1974; Eichler et al. 1989; Freiburghaus et al. 1999; Rosswog et al.1999, 2000).”
CHARGED-PARTICLE AND NEUTRON-CAPTURE PROCESSES IN THE HIGH-ENTROPY WIND OF CORE-COLLAPSE SUPERNOVAE (2010, background): “However, from the beginning problems were encountered to attain entropies sufficiently high in order to produce the heaviest r-process nuclei (see, e.g., Takahashi et al. 1994; Woosley et al. 1994; Thompson et al. 2001; Wanajo et al. 2001; Terasawa et al. 2002).”
Neutron star mergers versus core-collapse supernovae as dominant r-process sites in the early Galaxy (2003, background): “This amount is significantly larger than the typical 10−5 − 10−6M⊙ of r-process material thought to be ejected in each corecollapse SN event (Cowan et al. 1991; Woosley et al. 1994; Qian 2000; Wanajo et al. 2001).”
The rp-Process in Neutrino-driven Winds (2006, methodology): “(1)-(3) in Wanajo et al. 2001).”
Nucleosynthesis in the Early Galaxy (2007, methodology): “R-process scenarios such as the neutrino driven wind in supernovae and supernova fallback (Woosley & Hoffman 1992; Takahashi et al. 1994; Wanajo et al. 2001; Thompson et al. 2001; Farouqi et al. 2006; Fryer et al. 2006) have neutron densities that dramatically evolve with time.”
Toward a Mass and Radius Determination of the Nearby Isolated Neutron Star RX J185635–3754 (2001, background): “The large inferred compactness is not completely without precedent: for example, Wanajo et al. (2001) have recently argued that very compact stars (z ∼0.58) are required to explain the yield of r-process elements, if produced in a neutrino-driven wind.”
NUGRID STELLAR DATA SET. I. STELLAR YIELDS FROM H TO BI FOR STARS WITH METALLICITIES Z = 0.02 and Z = 0.01 (2013, background): “Proposed scenarios are the neutrinoinduced winds from the CCSNe, before the formation of the reverse shock (e.g., Woosley et al. 1994; Wanajo et al. 2001; Farouqi et al. 2010) or after the fallback started (e.g., Fryer et al. 2006; Arcones et al. 2007); the polar jets from rotating…”
Neutron-Capture Elements in the Very Metal Poor Star HD 122563 (2006, background): “Wanajo et al. (2001) have suggested that the small (but nonnegligible) amount of heavy r-process nuclei (A > 130) with a nonsolar r-process abundance pattern, in addition to the light r-process nuclei, can be produced in neutrino winds if the entropy of the neutrino-heated matter is high enough…”
Composition of the Innermost Core-Collapse Supernova Ejecta (2004, background): “…seconds after the supernova explosion, and considered as a possible source of the r -process to produce the heaviest elements via neutron captures (Takahashi et al. 1994; Woosley et al. 1994; Qian et al. 1997; Thompson et al. 2001; Wanajo et al. 2001; Terasawa et al. 2002; Thompson et al. 2003).”
Supernova Simulations with Boltzmann Neutrino Transport: A Comparison of Methods (2003, background): “…star surface causes a postexplosion outflow of baryonic matter, the so-called neutrino-driven wind, which is discussed as a potential site for the formation of r-process elements (Woosley et al. 1994; Takahashi et al. 1994; Sumiyoshi et al. 2000; Wanajo et al. 2001; Thompson et al. 2001).”
First stars VIII. Enrichment of the neutron-capture elements in the early Galaxy (2007, unknown): “…a second neutron-capture process for the synthesis of the first-peak elements, called the “weak” r-process (Busso et al. 1999; Qian & Wasserburg 2000; Wanajo et al. 2001), LEPP process (Travaglio et al. 2004), or CPR process (Qian & Wasserburg 2007), or even an entirely new nucleosynthesis…”