DOCSLIB.ORG

Routine Isotopic Analysis of Iron by HR-MC-ICPMS: How Precise and How Accurate?

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Routine Isotopic Analysis of Iron by HR-MC-ICPMS: How Precise and How Accurate? Chemical Geology 267 (2009) 175–184 Contents lists available at ScienceDirect Chemical Geology journal homepage: www.elsevier.com/locate/chemgeo Routine isotopic analysis of iron by HR-MC-ICPMS: How precise and how accurate? Nicolas Dauphas a,b,⁎, Ali Pourmand a,b, Fang-Zhen Teng a,b,1 a Origins Laboratory, Department of the Geophysical Sciences, the University of Chicago, 5734 South Ellis Avenue, Chicago IL 60637, USA b Enrico Fermi Institute, the University of Chicago, 5640 South Ellis Avenue, Chicago IL 60637, USA article info abstract Article history: High-temperature isotopic variations documented in natural materials span a narrow range and call for Received 14 June 2008 precise and accurate isotopic analyses. Precisions better than ~0.03‰ (95% confidence interval) for δ56Fe Received in revised form 16 November 2008 have been obtained by High-Resolution Multi-Collector Inductively Coupled Plasma Mass Spectrometry (HR- Accepted 5 December 2008 MC-ICPMS). Whether these uncertainties encompass all sources of error has not been carefully evaluated. The current study examines all parameters that can affect accuracy and precision of Fe isotopic Keywords: measurements by HR-MC-ICPMS. It is demonstrated that accurate δ56Fe measurements can be routinely Iron isotopes HR-MC-ICPMS achieved within the quoted uncertainties. Chromatography © 2008 Elsevier B.V. All rights reserved. Precision Accuracy 1. Introduction have variable compositions averaging ~0‰ (Williams et al., 2005; Schoenberg and von Blanckenburg, 2006; Weyer and Ionov, 2007). The field of Fe isotope geochemistry has seen important develop- Although increasing the number of repeats (n)inHighResolution ments in methodology and scope since the advent of Multi-Collector (HR-) MC-ICPMS reduces the uncertainty relatedp toffiffiffi instability in Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) (see recent instrumental mass bias and counting statistics (~1 = n), many other reviews by Anbar, 2004; Beard and Johnson, 2004; Johnson et al., 2004; parameters can affect the precision and accuracy of Fe isotopic analyses Dauphas and Rouxel, 2006). There is now increasing evidence that Fe (Malinovsky et al., 2003; Schoenberg and von Blanckenburg, 2005). isotopic variations are not confined to the realm of biology or low These include mass fractionation during column chromatography, temperature aqueous geochemistry but can also occur at high incomplete separation of Fe from matrix elements that can cause temperature by equilibrium fractionation between minerals and melts instrumental mass bias to vary, presence of direct isobars from 54Cr+ on (Polyakov and Mineev, 2000; Polyakov et al., 2007; Dauphas et al., 2007; 54Fe+ and 58Ni+ on 58Fe+ and imperfect matching in acid molarity or Fe Schuessler et al., 2007; Shahar et al., 2008), by diffusion in solid metal concentration between samples and bracketing standards. (Mullen, 1961; Roskosz et al., 2006; Dauphas, 2007 and references A major challenge in making precise and accurate measurements therein) and silicate melts (Richter et al., 2009), by evaporation/ of Fe isotopes arises from incomplete mass separation between Fe and condensation (Wang et al., 1994; Alexander and Hewins, 2004; Dauphas argides, which include interferences of 40Ar14N+, 40Ar16O+, and et al., 2004; Tachibana et al., 2007; Zipfel and Weyer, 2007), and by Soret 40Ar16O1H+ on 54Fe+, 56Fe+, and 57Fe+, respectively. Several strategies diffusion (Huang et al., in press; Richter et al., 2009). Considering that the have been employed to address this analytical difficulty and are briefly Fe isotopic compositions of most geomaterials formed at high tempera- discussed below. (i) The first method employed for isotopic analysis of ture span a narrow range, important unsettled questions require high Fe by MC-ICPMS relies on desolvating nebulization to increase the precision and accurate analyses. For instance, the Fe isotopic composition ratio of Fe/argide (Belshaw et al., 2000; Anbar et al., 2000; Zhu et al., of the silicate Earth is still uncertain. While basalts have almost 2002, de Jong et al., 2007). Nevertheless, this brute-force method is homogeneous δ56Fe around +0.1‰ (Beard et al., 2003; Schoenberg and incapable of eliminating all interferences and careful matching von Blanckenburg, 2006; Weyer and Ionov, 2007), mantle peridotites between standard and sample ion intensities during bracketing is essential. (ii) The GV IsoProble MC-ICPMS is equipped with a hexapole collision cell, which is primarily used to thermalize the incoming ions ⁎ Corresponding author. Origins Laboratory, Department of the Geophysical Sciences, before introduction into the magnetic sector. It also serves the purpose the University of Chicago, 5734 South Ellis Avenue, Chicago IL 60637, USA. of breaking down molecules such as argides through interaction with E-mail address: [email protected] (N. Dauphas). 1 Present address: Isotope Laboratory, Department of Geosciences and Arkansas the collision gas, a mixture of Ar and H2 for Fe isotopes (Beard et al., Center for Space and Planetary Sciences, University of Arkansas, 113 Ozark Hall, 2003; Rouxel et al., 2003; Dauphas et al., 2004). (iii) Operating the MC- Fayetteville, AR 72701, USA. ICPMS at reduced power (cold plasma) can also drastically reduce 0009-2541/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.chemgeo.2008.12.011 176 N. Dauphas et al. / Chemical Geology 267 (2009) 175–184 argide interferences (Kehm et al., 2003). The main drawback of this be a problem for certain matrices, such as sulfides. To mitigate this technique, however, is that it promotes formation of CaOH+, which problem, Schoenberg and von Blanckenburg (2005) introduced an iron 57 + can interfere with Fe peak. (iv) Medium to high mass-resolving hydroxide precipitation step by basification with NH4(OH). power on the Thermo Scientific Neptune, Nu-Plasma HR, and Nu Plasma 1700 are used to separate argide interferences from Fe isotopes 3. Mass spectrometry (Malinovsky et al., 2003; Weyer and Schwieters, 2003; Arnold et al., 2004; Poitrasson and Freydier, 2005; Schoenberg and von Blancken- Iron isotopic analyses were performed with a Thermo Scientific burg, 2005; Williams et al., 2005; Borrok et al., 2007). Precisions of Neptune HR-MC-ICPMS (see Wieser and Schwieters, 2005 for a better than 0.04‰ are achievable with this method. description of the instrument). The mass-resolution of the instrument In the current study, we evaluate the variables that can affect the is controlled with a set of three switchable slits (250 μm, 30 μm, and accuracy of Fe isotope measurements using HR-MC-ICPMS. Error bars 16 μm width) located before the electrostatic analyzer. Measurements in Fe isotope geochemistry have been traditionally ascribed based on were performed in both medium-resolution (MR) and high-resolution either the long-term external reproducibility of geostandards or the (HR) modes. In these two modes, the Fe+ peaks are resolved from argide dispersion of replicate analyses of a solution during a session of interferences as flat-topped shoulders on the low mass side of argide measurements. In the following, we present a method, which is also peaks (Weyer and Schwieters, 2003). The mass resolution is defined as applicable to other isotope systems, to take into account both sources m/(m0.95 −m0.05), where m0.95 and m0.05 are the masses measured at of analytical uncertainties. We demonstrate that δ56Fe can be 5% and 95% intensity peak heights (see Weyer and Schwieters, 2003, measured accurately at a precision of ~0.03‰ in rocks and minerals. for details). Mass resolutions are equal to ~8500 and ~11,000 for MR and HR, respectively. The ion transmission efficiency of the instru- 2. Chemical separation of iron ment for Fe is reduced by a factor of ~8 from LR to MR and another factor i i 54 of ~2 from MR to HR. The δ notation (in ‰), δ Fe=[( Fe/ Fe)sample / i 54 3 All chemical protocols used for Fe isotopic analyses rely on the ( Fe/ Fe)IRMM-014 −1]×10 , is used throughout the current study. partition behavior of Fe with anion-exchange resin in HCl medium IRMM-014 is a pure Fe metal reference material (Taylor et al., 1992)that (Strelow, 1980). Matrix and interfering elements are eluted with has a Fe isotopic composition identical to chondrites (Dauphas and concentrated HCl while Fe, which forms strong anion chloride- Rouxel, 2006). Unless otherwise noted, the pair of isotopes reported is complexes, is retained on the resin. Iron is subsequently eluted at 56Fe/54Fe (i=56). In the course of this study, the stock solution of IRMM- lower HCl molarity. Protocols using AG MP-1 anion exchange resin can 014 used during sample-standard bracketing was renewed. The δ56Fe be found in Maréchal et al. (1999), Archer and Vance (2004), Brantley et and δ57Fe of the new batch of IRMM-014 normalized to the old batch are al. (2004), Borrok et al. (2007) and de Jong et al. (2007). Protocols using −0.004±0.009‰ and 0.001±0.015‰ (95% ci), respectively. This AG1-X3, -X4 or -X8 are described in Rouxel et al. (2003), Dauphas et al. confirms the conclusion of Dauphas et al. (2004) that IRMM-014 has (2004), Poitrasson and Freydier (2005), Schoenberg and von Blancken- homogeneous isotopic composition at the 0.01‰ level. burg (2005), Dideriksen et al. (2006),andThompson et al. (2007). Except for a series of tests aimed at estimating the influence of acid Here we used the separation protocol described by Dauphas et al. molarity on isotopic ratios, all analyzed solutions were in 0.3 M HNO3. (2004, 2007).Typically2–10 mg of powdered sample is subjected to the An enclosed SC-2 sample changer installation (autosampler) sequence of acid addition and heating and evaporations presented in Table equipped with an ULPA filter unit was used throughout this study. 1.Thepurification procedure of column chromatography is repeated twice Most analyses were performed with the Thermo Scientific Stable to ensure complete elimination of the matrix.
Load more

Recommended publications
  • R-Process Elements from Magnetorotational Hypernovae
    r-Process elements from magnetorotational hypernovae D. Yong1,2*, C. Kobayashi3,2, G. S. Da Costa1,2, M. S. Bessell1, A. Chiti4, A. Frebel4, K. Lind5, A. D. Mackey1,2, T. Nordlander1,2, M. Asplund6, A. R. Casey7,2, A. F. Marino8, S. J. Murphy9,1 & B. P. Schmidt1 1Research School of Astronomy & Astrophysics, Australian National University, Canberra, ACT 2611, Australia 2ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australia 3Centre for Astrophysics Research, Department of Physics, Astronomy and Mathematics, University of Hertfordshire, Hatfield, AL10 9AB, UK 4Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA 5Department of Astronomy, Stockholm University, AlbaNova University Center, 106 91 Stockholm, Sweden 6Max Planck Institute for Astrophysics, Karl-Schwarzschild-Str. 1, D-85741 Garching, Germany 7School of Physics and Astronomy, Monash University, VIC 3800, Australia 8Istituto NaZionale di Astrofisica - Osservatorio Astronomico di Arcetri, Largo Enrico Fermi, 5, 50125, Firenze, Italy 9School of Science, The University of New South Wales, Canberra, ACT 2600, Australia Neutron-star mergers were recently confirmed as sites of rapid-neutron-capture (r-process) nucleosynthesis1–3. However, in Galactic chemical evolution models, neutron-star mergers alone cannot reproduce the observed element abundance patterns of extremely metal-poor stars, which indicates the existence of other sites of r-process nucleosynthesis4–6. These sites may be investigated by studying the element abundance patterns of chemically primitive stars in the halo of the Milky Way, because these objects retain the nucleosynthetic signatures of the earliest generation of stars7–13.
    [Show full text]
  • Concrete Analysis by Neutron-Capture Gamma Rays Using Californium 252
    CONCRETE ANALYSIS BY NEUTRON-CAPTURE GAMMA RAYS USING CALIFORNIUM 252 Dick Duffey, College of Engineering, University of Maryland; Peter F. Wiggins, Naval Systems Engineering Department, U.S. Naval Academy; Frank E. Senftle, U.S. Geological Survey; and A. A. El Kady, United Arab Republic Atomic Energy Establishment, Cairo The feasibility of analyzing concrete and cement by a measurement of the neutron-capture or prompt gamma rays was investigated; a 100-ug californium-252 source was used to supply the neutrons. A lithium drifted germanium crystal detected the capture gamma rays emitted. The capture gamma rays from cement, sand, and 3 coarse aggregates-quartzite gravel, limestone, and diabase--:were studied. Concrete blocks made from these materials were then tested. The capture gamma ray response of the calcium, silicon, and iron in the concrete blocks was in accord with the elements identified in the mix materials. The principal spectral lines used were the 6.42 MeV line of calcium, the 4.93 MeV line of silicon, and the doublet of iron at about 7 .64 MeV. The aluminum line at 7. 72 MeV was ob­ served in some cases but at a lower intensity with the limited electronic equipment available. This nuclear spectroscopic technique offers a possi­ ble method of determining the components of sizable concrete samples in a nondestructive, in situ manner. In addition, the neutron-capture gamma ray technique might find application in control of the concrete and cement processes and furnish needed information on production operations and inventories. • FROM THE point of view of the geochemical analyst, concrete may be considered as rock relocated and reformed at the convenience of the engineer.
    [Show full text]
  • Nuclear Astrophysics: the Unfinished Quest for the Origin of the Elements
    Nuclear astrophysics: the unfinished quest for the origin of the elements Jordi Jos´e Departament de F´ısica i Enginyeria Nuclear, EUETIB, Universitat Polit`ecnica de Catalunya, E-08036 Barcelona, Spain; Institut d’Estudis Espacials de Catalunya, E-08034 Barcelona, Spain E-mail: [email protected] Christian Iliadis Department of Physics & Astronomy, University of North Carolina, Chapel Hill, North Carolina, 27599, USA; Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708, USA E-mail: [email protected] Abstract. Half a century has passed since the foundation of nuclear astrophysics. Since then, this discipline has reached its maturity. Today, nuclear astrophysics constitutes a multidisciplinary crucible of knowledge that combines the achievements in theoretical astrophysics, observational astronomy, cosmochemistry and nuclear physics. New tools and developments have revolutionized our understanding of the origin of the elements: supercomputers have provided astrophysicists with the required computational capabilities to study the evolution of stars in a multidimensional framework; the emergence of high-energy astrophysics with space-borne observatories has opened new windows to observe the Universe, from a novel panchromatic perspective; cosmochemists have isolated tiny pieces of stardust embedded in primitive meteorites, giving clues on the processes operating in stars as well as on the way matter condenses to form solids; and nuclear physicists have measured reactions near stellar energies, through the combined efforts using stable and radioactive ion beam facilities. This review provides comprehensive insight into the nuclear history of the Universe arXiv:1107.2234v1 [astro-ph.SR] 12 Jul 2011 and related topics: starting from the Big Bang, when the ashes from the primordial explosion were transformed to hydrogen, helium, and few trace elements, to the rich variety of nucleosynthesis mechanisms and sites in the Universe.
    [Show full text]
  • Iron Isotope Cosmochemistry Kun Wang Washington University in St
    Washington University in St. Louis Washington University Open Scholarship All Theses and Dissertations (ETDs) 12-2-2013 Iron Isotope Cosmochemistry Kun Wang Washington University in St. Louis Follow this and additional works at: https://openscholarship.wustl.edu/etd Part of the Earth Sciences Commons Recommended Citation Wang, Kun, "Iron Isotope Cosmochemistry" (2013). All Theses and Dissertations (ETDs). 1189. https://openscholarship.wustl.edu/etd/1189 This Dissertation is brought to you for free and open access by Washington University Open Scholarship. It has been accepted for inclusion in All Theses and Dissertations (ETDs) by an authorized administrator of Washington University Open Scholarship. For more information, please contact [email protected]. WASHINGTON UNIVERSITY IN ST. LOUIS Department of Earth and Planetary Sciences Dissertation Examination Committee: Frédéric Moynier, Chair Thomas J. Bernatowicz Robert E. Criss Bruce Fegley, Jr. Christine Floss Bradley L. Jolliff Iron Isotope Cosmochemistry by Kun Wang A dissertation presented to the Graduate School of Arts and Sciences of Washington University in partial fulfillment of the requirements for the degree of Doctor of Philosophy December 2013 St. Louis, Missouri Copyright © 2013, Kun Wang All rights reserved. Table of Contents LIST OF FIGURES ....................................................................................................................... vi LIST OF TABLES ........................................................................................................................
    [Show full text]
  • Alpha Process
    Alpha process The alpha process, also known as the alpha ladder, is one of two classes of nuclear fusion reactions by which stars convert helium into heavier elements, the other being the triple-alpha process.[1] The triple-alpha process consumes only helium, and produces carbon. After enough carbon has accumulated, the reactions below take place, all consuming only helium and the product of the previous reaction. E is the energy produced by the reaction, released primarily as gamma rays (γ). It is a common misconception that the above sequence ends at (or , which is a decay product of [2]) because it is the most stable nuclide - i.e., it has the highest nuclear binding energy per nucleon, and production of heavier nuclei requires energy (is endothermic) instead of releasing it (exothermic). (Nickel-62) is actually the most stable nuclide.[3] However, the sequence ends at because conditions in the stellar interior cause the competition between photodisintegration and the alpha process to favor photodisintegration around iron,[2][4] leading to more being produced than . All these reactions have a very low rate at the temperatures and densities in stars and therefore do not contribute significantly to a star's energy production; with elements heavier than neon (atomic number > 10), they occur even less easily due to the increasing Coulomb barrier. Alpha process elements (or alpha elements) are so-called since their most abundant isotopes are integer multiples of four, the mass of the helium nucleus (the alpha particle); these isotopes are known as alpha nuclides. Stable alpha elements are: C, O, Ne, Mg, Si, and S; Ar and Ca are observationally stable.
    [Show full text]
  • Arxiv:1710.04254V5 [Astro-Ph.SR] 25 Jun 2019 Hr Xssawd Iest Nsei Se
    Accepted for publication in Astrophysical Journal Supplement, submitted on 19 September 2017, revised on 16 April 2018 Typeset using LATEX twocolumn style in AASTeX62 Explosive Nucleosynthesis in Near-Chandrasekhar Mass White Dwarf Models for Type Ia supernovae: Dependence on Model Parameters Shing-Chi Leung, Ken’ichi Nomoto1 1Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study The University of Tokyo, Kashiwa, Chiba 277-8583, Japan ABSTRACT We present two-dimensional hydrodynamics simulations of near-Chandrasekhar mass white dwarf (WD) models for Type Ia supernovae (SNe Ia) using the turbulent deflagration model with deflagration- detonation transition (DDT). We perform a parameter survey for 41 models to study the effects of the initial central density (i.e., WD mass), metallicity, flame shape, DDT criteria, and turbulent flame formula for a much wider parameter space than earlier studies. The final isotopic abundances of 11C to 91Tc in these simulations are obtained by post-process nucleosynthesis calculations. The survey includes SNe Ia models with the central density from 5 108 g cm−3 to 5 109 g cm−3 (WD masses × × of 1.30 - 1.38 M⊙), metallicity from 0 to 5 Z⊙, C/O mass ratio from 0.3 - 1.0 and ignition kernels including centered and off-centered ignition kernels. We present the yield tables of stable isotopes from 12C to 70Zn as well as the major radioactive isotopes for 33 models. Observational abundances of 55Mn, 56Fe, 57Fe and 58Ni obtained from the solar composition, well-observed SNe Ia and SN Ia remnants are used to constrain the explosion models and the supernova progenitor.
    [Show full text]
  • Abundance Gradients in the Milky Way for Α Elements, Iron Peak Elements, Barium, Lanthanum, and Europium
    A&A 462, 943–951 (2007) Astronomy DOI: 10.1051/0004-6361:20065403 & c ESO 2007 Astrophysics Abundance gradients in the Milky Way for α elements, iron peak elements, barium, lanthanum, and europium G. Cescutti1,F.Matteucci1,2,P.François3,4, and C. Chiappini2 1 Dipartimento di Astronomia, Universitá di Trieste, via G.B. Tiepolo 11, 34131 Trieste, Italy e-mail: [email protected] 2 I.N.A.F. Osservatorio Astronomico di Trieste, via G.B. Tiepolo 11, 34131 Trieste, Italy 3 Observatoire de Paris/Meudon, GEPI, 61 avenue de l’Observatoire, 75014 Paris, France 4 European Southern Observatory, Casilla 19001, Santiago 19, Chile Received 10 April 2006 / Accepted 25 September 2006 ABSTRACT We model the abundance gradients in the disk of the Milky Way for several chemical elements (O, Mg, Si, S, Ca, Sc, Ti, Co, V, Fe, Ni, Zn, Cu, Mn, Cr, Ba, La and Eu), and compare our results with the most recent and homogeneous observational data. We adopt a chemical evolution model able to well reproduce the main properties of the solar vicinity. The model assumes that the disk formed inside-out with a timescale for the formation of the thin disk of 7 Gyr in the solar vicinity, whereas the halo formed on a timescale of 0.8 Gyr. We adopt new empirical stellar yields derived to best fit the abundances and the abundance ratios in the solar vicinity. We compute, for the first time, the abundance gradients for all the mentioned elements in the galactocentric distance range 4–22 kpc. Comparison with the observed data on Cepheids in the galactocentric distance range 5–17 kpc gives a very good agreement for many of the studied elements.
    [Show full text]
  • Cobalt and Copper Abundances in 56 Galactic Bulge Red Giants ? H
    Astronomy & Astrophysics manuscript no. 37869corr c ESO 2020 July 2, 2020 Cobalt and copper abundances in 56 Galactic bulge red giants ? H. Ernandes1; 2; 3, B. Barbuy1, A. Friaça1, V. Hill4, M. Zoccali5; 6, D. Minniti6; 7; 8, A. Renzini9, and S. Ortolani10; 11 1 Universidade de São Paulo, IAG, Rua do Matão 1226, Cidade Universitária, São Paulo 05508-900, Brazil 2 UK Astronomy Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK 3 IfA, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK 4 Université de Sophia-Antipolis, Observatoire de la Côte d’Azur, CNRS UMR 6202, BP4229, 06304 Nice Cedex 4, France 5 Universidad Catolica de Chile, Departamento de Astronomia y Astrofisica, Casilla 306, Santiago 22, Chile 6 Millennium Institute of Astrophysics, Av. Vicuna Mackenna 4860, 782-0436, Santiago, Chile 7 Departamento de Ciencias Fisicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Av. Fernandez Concha 700, Las Condes, Santiago, Chile 8 Vatican Observatory, V00120 Vatican City State, Italy 9 Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy 10 Università di Padova, Dipartimento di Fisica e Astronomia, Vicolo dell’Osservatorio 2, I-35122 Padova, Italy 11 INAF-Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy ABSTRACT Context. The Milky Way bulge is an important tracer of the early formation and chemical enrichment of the Galaxy. The abundances of different iron-peak elements in field bulge stars can give information on the nucleosynthesis processes that took place in the earliest supernovae. Cobalt (Z=27) and copper (Z=29) are particularly interesting.
    [Show full text]
  • 56Ni, Explosive Nucleosynthesis, and Sne Ia Diversity
    56Ni, Explosive Nucleosynthesis, and SNe Ia Diversity James W Truran1,2, Ami S Glasner3, and Yeunjin Kim1 1Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637, USA 2Physics Division, Argonne National Laboratory, Argonne, IL 60439, USA 3Racah Institute of Physics, The Hebrew University, Jerusalem 91904, ISRAEL E-mail: [email protected] Abstract. The origin of the iron-group elements titanium to zinc in nature is understood to occur under explosive burning conditions in both Type Ia (thermonuclear) and Type II (core collapse) supernovae. In these dynamic environments, the most abundant product is found to be 56Ni ((τ = 8.5 days) that decays through 56Co (τ = 111.5 days) to 56Fe. For the case of SNe Ia, the peak luminosities are proportional to the mass ejected in the form of 56Ni. It follows that the diversity of SNe Ia reflected in the range of peak luminosity provides a direct measure of the mass of 56Ni ejected. In this contribution, we identify and briefly discuss the factors that can influence the 56Ni mass and use both observations and theory to quantify their impact. We address specifically the variations in different stellar populations and possible distinctions with respect to SNe Ia progenitors. 1. Introduction Dating back to the early work by Hoyle and Fowler [1], the ‘standard’ model for a Type Ia supernova has been assumed to involve the explosion of a carbon-oxygen (CO) white dwarf, with iron peak nuclei being a major product. The history of our understanding of supernova iron production began with Hoyle’s [2] identification of the nucleosynthesis mechanism with a “nuclear statistical equilibrium” process occurring at high temperatures and densities in stellar cores.
    [Show full text]
  • By Massive Stars
    The Alchemists or How the stars made the periodic table L. Sbordone And so it began Defines α-process, p- capture, s- and r- neutron capture, statistical equilibrium nucleosynthesis. 62 years later we are largely still there. Burbidge, Burbidge, Fowler & Hoyle 1957, a.k.a. “B2FH” And so it began Defines α-process, p- capture, s- and r- neutron capture, statistical equilibrium nucleosynthesis. 62 years later we are largely still there. Margaret Burbidge Burbidge, Burbidge, Fowler & turned 100 this year! Hoyle 1957, a.k.a. “B2FH” C,N, H He Li C,N, C,N,O α, Fe-peak, r-process H He Li C,N, C,N,O α, Fe-peak, r-process H He Li C,N, C,N,O α, Fe-peak, r-process C,N,O, light-odd, α, Fe- peak, r- process H He Li C,N, C,N,O α, Fe-peak, r-process C,N,O, light-odd, α, Fe- peak, r- process H He light-odd, Li s-process C,N, C,N,O α, Fe-peak, r-process C,N,O, light-odd, α, Fe- peak, r- process H Fe-peak He light-odd, Li s-process C,N, General concepts: nucleosynthesis • H, He, Li were synthesized in the high-temperature phase of early universe (BB Nucleosynthesis, 3 to 20 min after BB)… • … but almost 100% of everything else was synthesized in stars. • Stellar nucleosynthesis products are reintroduced in ISM at the end of the star life. New stars will be then born enriched of the product of previous generations. • What matters is not what the star makes, but what it can eject.
    [Show full text]
  • Stellar Nucleosynthesis
    21 November 2006 by JJG Stellar Nucleosynthesis Figure 1 shows the relative abundances of solar system elements versus atomic number Z, the number of protons in the nucleus. A theory of nucleosynthesis should explain this pattern. One believes, of course, that all but the lightest elements (Z > 4) are made in stars rather than the early universe, and primarily through nuclear fusion. Figure 1: Solar abundances by number, i.e. vertical axis is log(XZ /A¯Z ) + constant, where XZ is the abundance of element Z by mass and A¯Z is the mean atomic weight of that element. (C. R. Crowley, U Mich). It is clear that the pattern in Fig. 1 is not the result of thermal equilibrium: if it were, then iron ( 56Fe) would be the most abundant element since it is the most tightly bound. In fact, nuclear masses can be approximated by the semi-empirical mass formula [1] M(A, Z) = (A − Z)mn + Z(mp + me) 2 2 2/3 (A/2 − Z) Z δ − a1A + a2A + a3 + a4 + a5 . (1) A A1/3 A3/4 The coefficients have the following approximate values measured in MeV/c2: a1 − 15.53, a2 = 17.804, a3 = 94.77, a4 = 0.7103, a5 = 33.6. The first two terms on the righthand side represent the “free” rest masses of the neutron, 2 proton, and electron: mn ≈ 939.57, mp ≈ 938.27, me ≈ 0.511 MeV/c . The term in a1 represents an increase in the binding energy (i.e., decrease in nuclear mass) due to nearest- neighbor interactions between nucleons: to lowest order, nuclei are rather like drops of liquid, in which the interactions are very short range, and are attractive at low pressure but are strongly repulsive under compression; consequently, the liquid prefers to maintain 14 −3 a roughly constant density, which for nuclei is ρnuc ≈ 2 × 10 g cm , correponding to an 1 1/3 interparticle spacing a0 ≡ (3ρnuc/4πmp) ≈ 1.3 fm.
    [Show full text]
  • Iron-Peak Elements in the Solar Neighbourhood Š
    The AMBRE project: Iron-peak elements in the solar neighbourhood Š. Mikolaitis, P. de Laverny, A. Recio–blanco, V. Hill, C. C. Worley, M. de Pascale To cite this version: Š. Mikolaitis, P. de Laverny, A. Recio–blanco, V. Hill, C. C. Worley, et al.. The AMBRE project: Iron-peak elements in the solar neighbourhood. Astronomy and Astrophysics - A&A, EDP Sciences, 2017, 600, pp.A22. 10.1051/0004-6361/201629629. hal-03118590 HAL Id: hal-03118590 https://hal.archives-ouvertes.fr/hal-03118590 Submitted on 22 Jan 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. A&A 600, A22 (2017) Astronomy DOI: 10.1051/0004-6361/201629629 & c ESO 2017 Astrophysics The AMBRE project: Iron-peak elements in the solar neighbourhood?,?? Š. Mikolaitis1; 2, P. de Laverny2, A. Recio–Blanco2, V. Hill2, C. C. Worley3, and M. de Pascale4 1 Institute of Theoretical Physics and Astronomy, Vilnius University, Sauletekio˙ al. 3, 10257 Vilnius, Lithuania e-mail: [email protected] 2 Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange, Bd de l’Observatoire, CS_34229, 06304 Nice Cedex 4, France 3 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 4 INAF–Padova Observatory, Vicolo dell’Osservatorio 5, 35122 Padova, Italy Received 1 September 2016 / Accepted 24 November 2016 ABSTRACT Context.
    [Show full text]