Radioactive heat production of six geologically important nuclides

Ruedas, Thomas

doi:10.1002/2017gc006997

Cited by 26 publications

(26 citation statements)

References 65 publications

(136 reference statements)

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“…Furthermore, the time rate of heat production is sensitive to the value of the decay constant. This study differs from other recent efforts (Dye, 2012; Enomoto, 2006a; Fiorentini et al., 2007; Ruedas, 2017; Usman et al., 2015) in its input assumptions; we use decay constants and branching fractions from geochronological studies and we calculate the beta decay energy spectrum for most of the SLR and 40 K decays. For the remaining LLR decays, we adopt the energy spectra from Enomoto (2006b).…”

Section: Contrasting Methodologiesmentioning

confidence: 99%

“…Radioactive decay inside the Earth produces heat, which in turn contributes power to driving the Earth's dynamic processes (i.e., mantle convection, volcanism, plate tectonics, and potentially the geodynamo). The physics community, using the latest numbers from nuclear physics databases, provides estimates of the present‐day radiogenic heating rate and geoneutrino luminosity (i.e., number of particles per unit of time) of the Earth (Dye, 2012; Enomoto, 2006a; Fiorentini et al., 2007; Ruedas, 2017; Usman et al., 2015). These studies include comprehensive reviews of the fundamental physics of these decay schemes, covering both the energy added to the Earth and that removed by the emitted geoneutrinos.…”

Section: Introductionmentioning

confidence: 99%

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Radiogenic Power and Geoneutrino Luminosity of the Earth and Other Terrestrial Bodies Through Time

McDonough

Šrámek

Wipperfurth

2020

Geochem Geophys Geosyst

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We report the Earth's rate of radiogenic heat production and (anti)neutrino luminosity from geologically relevant short‐lived radionuclides (SLR) and long‐lived radionuclides (LLR) using decay constants from the geological community, updated nuclear physics parameters, and calculations of the β spectra. We track the time evolution of the radiogenic power and luminosity of the Earth over the last 4.57 billion years, assuming an absolute abundance for the refractory elements in the silicate Earth and key volatile/refractory element ratios (e.g., Fe/Al, K/U, and Rb/Sr) to set the abundance levels for the moderately volatile elements. The relevant decays for the present‐day heat production in the Earth (19.9 ± 3.0 TW) are from 40K, 87Rb, 147Sm, 232Th, 235U, and 238U. Given element concentrations in kg‐element/kg‐rock and density ρ in kg/m3, a simplified equation to calculate the present‐day heat production in a rock is h[μW m−3]=ρ3.387×10−3K+0.01139Rb+0.04595Sm+26.18Th+98.29U The radiogenic heating rate of Earth‐like material at solar system formation was some 103 to 104 times greater than present‐day values, largely due to decay of 26Al in the silicate fraction, which was the dominant radiogenic heat source for the first ∼10 Ma. Assuming instantaneous Earth formation, the upper bound on radiogenic energy supplied by the most powerful short‐lived radionuclide 26Al (t1/2 = 0.7 Ma) is 5.5×1031 J, which is comparable (within a factor of a few) to the planet's gravitational binding energy.

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Section: Contrasting Methodologiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Radiogenic Power and Geoneutrino Luminosity of the Earth and Other Terrestrial Bodies Through Time

McDonough

Šrámek

Wipperfurth

2020

Geochem Geophys Geosyst

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“…The mesh resolution is set by 1000 nodes across the mantle. Our model includes internal heating due to the long-lived radiogenic isotopes ( 40 K, 232 Th, 235 U, 238 U), where the half-lives and present-day fractional abundances are provided by Ruedas (2017). We assume the mantle is undepleted (fertile) to estimate the heating rate per unit mass (p. 170, Turcotte & Schubert 2014).…”

Section: Dynamic Interior Modelmentioning

confidence: 99%

Linking the evolution of terrestrial interiors and an early outgassed atmosphere to astrophysical observations

Bower

Kitzmann

Wolf

et al. 2019

A&A

107

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Context. A terrestrial planet is molten during formation and may remain molten due to intense insolation or tidal forces. Observations favour the detection and characterisation of hot planets, potentially with large outgassed atmospheres. Aims. We aim to determine the radius of hot Earth-like planets with large outgassing atmospheres. Our goal is to explore the differences between molten and solid silicate planets on the mass–radius relationship and transmission and emission spectra. Methods. An interior–atmosphere model was combined with static structure calculations to track the evolving radius of a hot rocky planet that outgasses CO2 and H2O. We generated synthetic emission and transmission spectra for CO2 and H2O dominated atmospheres. Results. Atmospheres dominated by CO2 suppress the outgassing of H2O to a greater extent than previously realised since previous studies applied an erroneous relationship between volatile mass and partial pressure. We therefore predict that more H2O can be retained by the interior during the later stages of magma ocean crystallisation. Formation of a surface lid can tie the outgassing of H2O to the efficiency of heat transport through the lid, rather than the radiative timescale of the atmosphere. Contraction of the mantle, as it cools from molten to solid, reduces the radius by around 5%, which can partly be offset by the addition of a relatively light species (e.g. H2O versus CO2) to the atmosphere. Conclusions. A molten silicate mantle can increase the radius of a terrestrial planet by around 5% compared to its solid counterpart, or equivalently account for a 13% decrease in bulk density. An outgassing atmosphere can perturb the total radius, according to its composition, notably the abundance of light versus heavy volatile species. Atmospheres of terrestrial planets around M-stars that are dominated by CO2 or H2O can be distinguished by observing facilities with extended wavelength coverage (e.g. JWST).

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“…Furthermore, the time rate of heat production is sensitive to the value of the decay constant. This study differs from other recent efforts (Dye, 2012;Ruedas, 2017;Usman et al, 2015;Enomoto, 2006a;Fiorentini et al, 2007) in its input assumptions; we use decay constants and branching fractions from geochronological studies and we calculate the beta decay energy spectrum for most of the SLR and 40 K decays. For the remaining LLR decays, we adopt the energy spectra from Enomoto (2006b).…”

Section: Contrasting Methodologiesmentioning

confidence: 99%

“…In our comparison and where possible, we used the abundances and masses reported in Table 3 to carry out these comparisons. The calculated BSE radiogenic power in the models of Enomoto (2006a), Dye (2012), and Ruedas (2017) 4 Secular variation in the heat and luminosity of the Earth Secular evolution of the Earth's heat production reveals that only two of the shortlived radionuclides, 26 Al, and 60 Fe, contribute any significant amount of additional heat-ing to the accreting Earth above the power coming from the long-lived radionuclides (Figure 4). Formation and growth of the Earth is envisaged as a process that occurred on timescales of 10 7 years.…”

Section: Radiogenic Heat and Geoneutrino Luminosity Of The Earthmentioning

confidence: 99%

Radiogenic power and geoneutrino luminosity of the Earth and other terrestrial bodies through time

McDonough

Šrámek

Wipperfurth

2019

Preprint

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Key Points:• Radiogenic heat production and geoneutrino luminosity calculated over the age of the Earth • Simple formulae proposed for evaluation at arbitrary planetary composition • Differences in radioactive decay parameters highlighted between nuclear physics and geological communities AbstractWe report the Earth's rate of radiogenic heat production and (anti)neutrino luminosity from geologically relevant short-lived radionuclides (SLR) and long-lived radionuclides (LLR) using decay constants from the geological community, updated nuclear physics parameters, and calculations of the β spectra. We carefully account for all branches in 40 K decay using the updated β − energy spectrum from physics and an updated branching ratio from geological studies. We track the time evolution of the radiogenic power and luminosity of the Earth over the last 4.57 billion years, assuming an absolute abundance for the refractory elements in the silicate Earth and key volatile/refractory element ratios (e.g., Fe/Al, K/U, and Rb/Sr) to set the abundance levels for the moderately volatile elements. The relevant decays for the present-day heat production in the Earth (19.9 ± 3.0 TW) are from 40 K, 87 Rb, 147 Sm, 232 Th, 235 U, and 238 U. Given element concentrations in kg-element/kg-rock and density ρ in kg/m 3 , a simplified equation to calculate the heat production in a rock is:3.387 × 10 −3 [K] + 0.01139 [Rb] + 0.04607 [Sm] + 26.18 [Th] + 98.29 [U]The radiogenic heating rate of earth-like material at Solar System formation was some 10 3 to 10 4 times greater than present-day values, largely due to decay of 26 Al in the silicate fraction, which was the dominant radiogenic heat source for the first ∼ 10 My. Decay of 60 Fe contributed a non-negligible amount of heating during the first ∼ 15 My after CAI (Calcium Aluminum Inclusion) formation, interestingly within the time frame of core-mantle segregation. Using factors and equations presented here, one can calculate the first-order thermal and (anti)neutrino luminosity history of various size bodies in the solar system and exoplanets. Plain Language SummaryThe decay of radioactive elements in planetary interior's produces heat that drives the dynamic processes of convection (core and mantle), melting and volcanism in rocky bodies in the solar system and beyond. For elements with half-lives of 100,000 to 100 billion years, uncertainties in their decay constants range from 0.2% to ∼ 4% absolute and about 1% to 4% relative when comparing data sources in physics and geology. These differences, combined with uncertainties in Q (heat of reaction) values, lead to diverging results for heat production and for predictions of the amount of energy removed from the rocky body by emitted (anti)neutrinos.

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Radioactive heat production of six geologically important nuclides

Cited by 26 publications

References 65 publications

Radiogenic Power and Geoneutrino Luminosity of the Earth and Other Terrestrial Bodies Through Time

Radiogenic Power and Geoneutrino Luminosity of the Earth and Other Terrestrial Bodies Through Time

Linking the evolution of terrestrial interiors and an early outgassed atmosphere to astrophysical observations

Radiogenic power and geoneutrino luminosity of the Earth and other terrestrial bodies through time

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