Influence of the C/O ratio on titanium and vanadium oxides in protoplanetary disks

Ali-Dib, Mohamad; Mousis, O.; Pekmezci, G. S.; Lunine, Jonathan I.; Madhusudhan, Nikku; Petit, J. M.

doi:10.1051/0004-6361/201321780

Cited by 6 publications

(2 citation statements)

References 39 publications

(64 reference statements)

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“…The condensation sequence of the different nuclei follows their different volatility [275]. For ESS conditions, the most refractory element among the radioactive isotopes listed in this work is Hf (however, it will have a low spatial concentration), followed by Al (which is much more abundant and forms oxides like corundum, hibonite and gehlenite minerals around 1700 K), followed by the condensation of Nb, Be and Fe around 1500-1300 K (these could be present in enstatite and forsterite silicates formed around 1400 K but only at the trace amount level).…”

Section: Incorporation Into Mineralsmentioning

confidence: 99%

Radioactive nuclei from cosmochronology to habitability

Lugaro

Ott

Keresztúri

2018

Progress in Particle and Nuclear Physics

109

101

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In addition to long-lived radioactive nuclei like U and Th isotopes, which have been used to measure the age of the Galaxy, also radioactive nuclei with half-lives between 0.1 and 100 million years (short-lived radionuclides, SLRs) were present in the early Solar System (ESS), as indicated by high-precision meteoritic analysis. We review the most recent meteoritic data and describe the nuclear reaction processes responsible for the creation of SLRs in different types of stars and supernovae. We show how the evolution of radionuclide abundances in the Milky Way Galaxy can be calculated based on their stellar production. By comparing predictions for the evolution of galactic abundances to the meteoritic data we can build up a time line for the nucleosynthetic events that predated the birth of the Sun, and investigate the lifetime of the stellar nursery where the Sun was born. We then review the scenarios for the circumstances and the environment of the birth of the Sun within such a stellar nursery that have been invoked to explain the abundances in the ESS of the SLRs with the shortest lives -of the order of million years or less. Finally, we describe how the heat generated by radioactive decay and in particular by the abundant 26 Al in the ESS had important consequences for the thermo-mechanical and chemical evolution of planetesimals, and discuss possible implications on the habitability of terrestrial-like planets. We conclude with a set of open questions and future directions related to our understanding of the nucleosynthetic processes responsible for the production of SLRs in stars, their evolution in the Galaxy, the birth of the Sun, and the connection with the habitability of extra-solar planets.

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Section: Incorporation Into Mineralsmentioning

confidence: 99%

Radioactive nuclei from cosmochronology to habitability

Lugaro

Ott

Keresztúri

2018

Progress in Particle and Nuclear Physics

109

101

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“…Similarly, but at significantly higher temperatures, the study of molecules in the atmospheres of brown dwarfs and cool stars requires comprehensive datasets of spectral absorptions by a range of diatomic species whose vibronic transitions absorb near the peak flux of the object under study (Rajpurohit et al 2013). Similar species are also thought to be important constituents of the atmospheres of hot exoplanets (Ali-Dib et al 2014, Stevenson et al 2014, although there are as yet no confirmed observations of such spectra from a specific molecule. The spectra of these species also provide important diagnostics for those interested in probing hot environments.…”

Section: Introductionmentioning

confidence: 99%

The {\it ab initio} calculation of spectra of open shell diatomic molecules

Tennyson,

Lodi,

McKemmish

et al. 2016

Preprint

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The spectra (rotational, rotation-vibrational or electronic) of diatomic molecules due to transitions involving only closed-shell ( 1 Σ) electronic states follow very regular, simple patterns and their theoretical analysis is usually straightforward. On the other hand, open-shell electronic states lead to more complicated spectral patterns and, moreover, often appear as a manifold of closely lying electronic states, leading to perturbations with even larger complexity. This is especially true when at least one of the atoms is a transition metal. Traditionally these complex cases have been analysed using approaches based on perturbation theory, with semi-empirical parameters determined by fitting to spectral data.Recently the needs of two rather diverse scientific areas have driven the demand for improved theoretical models of open-shell diatomic systems based on an ab initio approach; these areas are ultracold chemistry and the astrophysics of "cool" stars, brown dwarfs and most recently extrasolar planets. However, the complex electronic structure of these molecules combined with the accuracy requirements of high-resolution spectroscopy render such an approach particularly challenging. This review describes recent progress in developing methods for directly solving the effective Schrödinger equation for open-shell diatomic molecules, with a focus on molecules containing a transtion metal. It considers four aspects of the problem: (i)The electronic structure problem; (ii)Non-perturbative treatments of the curve couplings; (iii)The solution of the nuclear motion Schrödinger equation; (iv)The generation of accurate electric dipole transition intensities.Examples of applications are used to illustrate these issues.

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