Cosmic radioactivities

Arnould, M.; Prantzos, Nikos

doi:10.1016/s1384-1076(99)00016-0

Cited by 7 publications

(4 citation statements)

References 89 publications

(154 reference statements)

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“…We thus find that contrary to usual expectations (e.g. Arnould and Prantzos 1999;Mowlavi & Meynet 2000), normal low-mass C stars with low Ṁ could produce abundant 26 Al and they are reasonable targets for gamma-ray line observations by high-energy satellite experiments like INTEGRAL. However, low 12 C/ 13 C requires low T P that is not compatible with significant 26 Al/ 27 Al.…”

Section: Astronomical Implicationscontrasting

confidence: 93%

Cool Bottom Processes on the Thermally Pulsing Asymptotic Giant Branch and the Isotopic Composition of Circumstellar Dust Grains

Nollett

Busso

Wasserburg

2003

ApJ

264

368

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We examine the effects of cool bottom processing (CBP) on the isotopic ratios 18 O/ 16 O, 17 O/ 16 O, 14 N/ 15 N, 26 Al/ 27 Al, C/O, and N/O in the convective envelope during the thermally-pulsing asymptotic giant branch (TP-AGB) phase of evolution in a 1.5M ⊙ initial-mass star of solar initial composition. We use a parametric model which treats extra mixing by introducing mass flow between the convective envelope and the underlying radiative zone. The parameters of this model are the mass circulation rate (Ṁ ) and the maximum temperature (T P ) experienced by the circulating material. The effects of nuclear reactions in the flowing matter were calculated using a set of static structures of the radiative zone selected from particular times in a complete stellar evolution calculation. The compositions of the flowing material were obtained and the resulting changes in the envelope determined. No major shifts in the star's energy budget occur from the imposed CBP if log T P < 7.73. Using structures from several times on the TP-AGB, it was found that the results for all species except 26 Al were essentially independent of the time chosen if log T P > 7.6. Abundant 26 Al was produced by CBP for log T P > 7.65. While 26 Al/ 27 Al depends on T P , the other isotopic ratios depend dominantly on the circulation rate. The relationship is shown between models of CBP as parameterized by a diffusion formalism within the stellar evolution model

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Section: Astronomical Implicationscontrasting

confidence: 93%

Cool Bottom Processes on the Thermally Pulsing Asymptotic Giant Branch and the Isotopic Composition of Circumstellar Dust Grains

Nollett

Busso

Wasserburg

2003

ApJ

264

368

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“…Accounts of some of these findings can be found in reviews by Podosek & Swindle (1988), Podosek & Nichols (1997) and Arnould & Prantzos (1999). The 60 Fe is a critical problem which we discuss extensively.…”

Section: Se Non è Vero è Bene Trovato Ancient Italian Motto 1 Introdumentioning

confidence: 83%

“…A wealth of new data subsequently became available on a variety of short-lived nuclei: 182 Hf (Harper & Jacobsen 1994Lee & Halliday 1995, 1998Yin et al 2002), 41 Ca (Srinivasan et al 1994(Srinivasan et al , 1996Sahijpal et al 1998), 53 Mn (Birck & Allègre 1985;Rotaru et al 1992;Lugmair & Shukolyukov 1998), 60 Fe (Shukolyukov & Lugmair 1993a, 1993b) and 10 Be (McKeegan et al 2000). Accounts of some of these findings can be found in reviews by Podosek & Swindle (1988), Podosek & Nichols (1997) and Arnould & Prantzos (1999). The 60 Fe is a critical problem which we discuss extensively.…”

Section: Se Non è Vero è Bene Trovatomentioning

confidence: 95%

Short-Lived Nuclei in the Early Solar System: A Low Mass Stellar Source?

Busso

Gallino

Wasserburg³

2003

Publ. – Astron. Soc. Aust

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Abstract:We discuss possible stellar origins of short-lived radioactive nuclei with meanlifeτ ≤ 100 Myr, which were shown to be alive in the Early Solar System (ESS). We first review current ideas on the production of nuclides having 10 ≤τ ≤ 100 Myr, which presumably derive from the continuous interplay of galactic astration, nucleosynthesis from massive supernovae and free decay in the interstellar medium. The abundance of the shorter lived 53 Mn might be explained by this same scenario. Then we consider the nuclei 107 Pd, 26 Al, 41 Ca and 60 Fe, whose early solar system abundances are too high to have originated in this way. Present evidence favours a stellar origin, particularly for 107 Pd, 26 Al and 60 Fe, rather than an in situ production by energetic solar particles. The idea of an encounter (rather close in time and space) between the forming Sun and a dying star is therefore discussed: this star may or may not have also triggered the solar formation. Recent nucleosynthesis calculations for the yields of the relevant short-lived isotopes and of their stable reference nuclei are discussed. Massive stars evolving to type II supernovae (either leaving a neutron star or a black hole as a remnant) seem incapable of explaining the four most critical ESS radioactivities in their observed abundance ratios. An asymptotic giant branch (AGB) star seems to be a viable source, especially if of relatively low initial mass (M ≤ 3M ⊙ ) and with low neutron exposure: this model can provide a solution for 26 Al, 41 Ca and 107 Pd, with important contributions to 60 Fe, which are inside the present uncertainty range of the 60 Fe early solar system abundance. Such a model requires that 26 Al is produced substantially on the AGB by cool bottom processing. The remaining inventory of short-lived species in the solar nebula would then be attributed to the continuous galactic processing, with the exception of 10 Be, which must reflect production by later proton bombardment at a low level during early solar history.

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“…The author whose father was a chemist has been predicting for several years that eventually this whole topic will be understood well enough that you could remember what all the various radioactivities and anomalies and their meanings are just by looking at a periodic table. This has not so far happened (see Arnould & Prantzos 1999 for an overview). What index year 2000 did see was (1) evidence for short-lived radioactivities and grain heating being quite inhomogeneous through the solar nebula (Meibon et al 2000 on heating;Guan et al 2000 on chemical inhomogeneities;Lugaro et al 1999), and (2) evidence suggesting that the various fossil radioactivities originated in more than one sort of site and process.…”

Section: Global Issuesmentioning

confidence: 99%

Astrophysics in 2000

Trimble

Aschwanden

2001

PUBL ASTRON SOC PAC

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It was a year in which some topics selected themselves as important through the sheer numbers of papers published. These include the connection(s) between galaxies with active central engines and galaxies with starbursts, the transition from asymptotic giant branch stars to white dwarfs, gamma-ray bursters, solar data from three major satellite missions, and the cosmological parameters, including dark matter and very large scale structure. Several sections are oriented around processes-accretion, collimation, mergers, and disruptions-shared by a number of kinds of stars and galaxies. And, of course, there are the usual frivolities of errors, omissions, exceptions, and inventories.

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Cosmic radioactivities

Cited by 7 publications

References 89 publications

Cool Bottom Processes on the Thermally Pulsing Asymptotic Giant Branch and the Isotopic Composition of Circumstellar Dust Grains

Cool Bottom Processes on the Thermally Pulsing Asymptotic Giant Branch and the Isotopic Composition of Circumstellar Dust Grains

Short-Lived Nuclei in the Early Solar System: A Low Mass Stellar Source?

Astrophysics in 2000

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