Chemical Evolution of 244Pu in the Solar Vicinity and Its Implications for the Properties of r-process Production

Takuji Tsujimoto, Tetsuya Yokoyama, Kenji Bekki

    Research output: Contribution to journalArticle

    7 Citations (Scopus)

    Abstract

    Meteoritic abundances of r-process elements are analyzed to deduce the history of chemical enrichment by the r-process, from the beginning of disk formation to the present time in the solar vicinity. Our analysis combines the abundance information from short-lived radioactive nuclei such as 244Pu with the abundance information from stable r-process nuclei such as Eu. These two types of nuclei can be associated with one r-process event and an accumulation of events until the formation of the solar system, respectively. With the help of the observed local star formation (SF) history, we deduce the chemical evolution of 244Pu and obtain three main results: (i) the last r-process event occurred 130-140 Myr before the formation of the solar system; (ii) the present-day low 244Pu abundance as measured in deep-sea reservoirs results from the low recent SF rate compared to ∼4.5-5 Gyr ago; and (iii) there were ∼15 r-process events in the solar vicinity from the formation of the Galaxy to the time of solar system's formation and ∼30 r-process events to the present time. Then, adopting the hypothesis that a neutron star (NS) merger is the r-process production site, we find that the ejected r-process elements are extensively spread out and mixed with interstellar matter, with a mass of M o, which is about 100 times larger than that for supernova ejecta. In addition, the event frequency of r-process production is estimated to be 1 per ∼1400 core-collapse supernovae, which is identical to the frequency of NS mergers estimated from the analysis of stellar abundances.

    Original languageEnglish
    Article numberL3
    JournalAstrophysical Journal Letters
    Volume835
    Issue number1
    DOIs
    Publication statusPublished - 20 Jan 2017

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    chemical evolution
    solar system
    merger
    neutron stars
    nuclei
    supernovae
    histories
    interstellar matter
    history
    ejecta
    deep sea
    star formation rate
    chemical
    star formation
    galaxies
    analysis

    Cite this

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    abstract = "Meteoritic abundances of r-process elements are analyzed to deduce the history of chemical enrichment by the r-process, from the beginning of disk formation to the present time in the solar vicinity. Our analysis combines the abundance information from short-lived radioactive nuclei such as 244Pu with the abundance information from stable r-process nuclei such as Eu. These two types of nuclei can be associated with one r-process event and an accumulation of events until the formation of the solar system, respectively. With the help of the observed local star formation (SF) history, we deduce the chemical evolution of 244Pu and obtain three main results: (i) the last r-process event occurred 130-140 Myr before the formation of the solar system; (ii) the present-day low 244Pu abundance as measured in deep-sea reservoirs results from the low recent SF rate compared to ∼4.5-5 Gyr ago; and (iii) there were ∼15 r-process events in the solar vicinity from the formation of the Galaxy to the time of solar system's formation and ∼30 r-process events to the present time. Then, adopting the hypothesis that a neutron star (NS) merger is the r-process production site, we find that the ejected r-process elements are extensively spread out and mixed with interstellar matter, with a mass of M o, which is about 100 times larger than that for supernova ejecta. In addition, the event frequency of r-process production is estimated to be 1 per ∼1400 core-collapse supernovae, which is identical to the frequency of NS mergers estimated from the analysis of stellar abundances.",
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    Chemical Evolution of 244Pu in the Solar Vicinity and Its Implications for the Properties of r-process Production. / Tsujimoto, Takuji; Yokoyama, Tetsuya; Bekki, Kenji.

    In: Astrophysical Journal Letters, Vol. 835, No. 1, L3, 20.01.2017.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Chemical Evolution of 244Pu in the Solar Vicinity and Its Implications for the Properties of r-process Production

    AU - Tsujimoto, Takuji

    AU - Yokoyama, Tetsuya

    AU - Bekki, Kenji

    PY - 2017/1/20

    Y1 - 2017/1/20

    N2 - Meteoritic abundances of r-process elements are analyzed to deduce the history of chemical enrichment by the r-process, from the beginning of disk formation to the present time in the solar vicinity. Our analysis combines the abundance information from short-lived radioactive nuclei such as 244Pu with the abundance information from stable r-process nuclei such as Eu. These two types of nuclei can be associated with one r-process event and an accumulation of events until the formation of the solar system, respectively. With the help of the observed local star formation (SF) history, we deduce the chemical evolution of 244Pu and obtain three main results: (i) the last r-process event occurred 130-140 Myr before the formation of the solar system; (ii) the present-day low 244Pu abundance as measured in deep-sea reservoirs results from the low recent SF rate compared to ∼4.5-5 Gyr ago; and (iii) there were ∼15 r-process events in the solar vicinity from the formation of the Galaxy to the time of solar system's formation and ∼30 r-process events to the present time. Then, adopting the hypothesis that a neutron star (NS) merger is the r-process production site, we find that the ejected r-process elements are extensively spread out and mixed with interstellar matter, with a mass of M o, which is about 100 times larger than that for supernova ejecta. In addition, the event frequency of r-process production is estimated to be 1 per ∼1400 core-collapse supernovae, which is identical to the frequency of NS mergers estimated from the analysis of stellar abundances.

    AB - Meteoritic abundances of r-process elements are analyzed to deduce the history of chemical enrichment by the r-process, from the beginning of disk formation to the present time in the solar vicinity. Our analysis combines the abundance information from short-lived radioactive nuclei such as 244Pu with the abundance information from stable r-process nuclei such as Eu. These two types of nuclei can be associated with one r-process event and an accumulation of events until the formation of the solar system, respectively. With the help of the observed local star formation (SF) history, we deduce the chemical evolution of 244Pu and obtain three main results: (i) the last r-process event occurred 130-140 Myr before the formation of the solar system; (ii) the present-day low 244Pu abundance as measured in deep-sea reservoirs results from the low recent SF rate compared to ∼4.5-5 Gyr ago; and (iii) there were ∼15 r-process events in the solar vicinity from the formation of the Galaxy to the time of solar system's formation and ∼30 r-process events to the present time. Then, adopting the hypothesis that a neutron star (NS) merger is the r-process production site, we find that the ejected r-process elements are extensively spread out and mixed with interstellar matter, with a mass of M o, which is about 100 times larger than that for supernova ejecta. In addition, the event frequency of r-process production is estimated to be 1 per ∼1400 core-collapse supernovae, which is identical to the frequency of NS mergers estimated from the analysis of stellar abundances.

    KW - Galaxy: evolution

    KW - meteorites, meteors, meteoroids

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    DO - 10.3847/2041-8213/835/1/L3

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    JO - The Astrophysical Journal Letters

    JF - The Astrophysical Journal Letters

    SN - 2041-8205

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