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Edward D Young - One of the best experts on this subject based on the ideXlab platform.
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bayes theorem and early Solar short lived radionuclides the case for an unexceptional origin for the Solar System
The Astrophysical Journal, 2016Co-Authors: Edward D YoungAbstract:The presence of excesses of short-lived radionuclides in the early Solar System evidenced in meteorites has been taken as testament to close encounters with exotic nucleosynthetic sources, including supernovae or AGB stars. An analysis of the likelihoods associated with different sources of these extinct nuclides in the early Solar System indicates that, rather than being exotic, their abundances were typical of star-forming regions like those observed today in the Galaxy. The radiochemistry of the early Solar System is therefore unexceptional, being the consequence of extensive averaging of solids from molecular clouds.
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inheritance of Solar short and long lived radionuclides from molecular clouds and the unexceptional nature of the Solar System
Earth and Planetary Science Letters, 2014Co-Authors: Edward D YoungAbstract:Article history: Al 60 Fe Apparent excesses in early-Solar 26 Al, 36 Cl, 41 Ca, and 60 Fe disappear if one accounts for ejecta from massive-star winds concentrated into dense phases of the ISM in star-forming regions. The removal of apparent excesses is evident when wind yields from Wolf-Rayet stars are included in the plot of radionuclide abundances vs. mean life. The resulting trend indicates that the Solar radionuclides were inherited from parental molecular clouds with a characteristic residence time of 10 8 yr. This residence time is of the same order as the present-day timescale for conversion of molecular cloud material into stars. The concentrations of these extinct isotopes in the early Solar System need not signify injection from unusual proximal stellar sources, but instead are well explained by normal concentrations in average star-forming clouds. The results imply that the efficiency of capture is greater for stellar winds than for supernova ejecta proximal to star-forming regions.
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astronomical oxygen isotopic evidence for supernova enrichment of the Solar System birth environment by propagating star formation
The Astrophysical Journal, 2011Co-Authors: Edward D Young, Matthieu Gounelle, Rachel L Smith, Mark Morris, K M PontoppidanAbstract:New infrared absorption measurements of oxygen isotope ratios in CO gas from individual young stellar objects confirm that the Solar System is anomalously high in its [^(18)O]/[^(17)O] ratio compared with extraSolar oxygen in the Galaxy. We show that this difference in oxygen isotope ratios is best explained by ~1% enrichment of the protoSolar molecular cloud by ejecta from Type II supernovae from a cluster having of order a few hundred stars that predated the Sun by at least 10-20 Myr. The likely source of exogenous oxygen was the explosion of one or more B stars during a process of propagating star formation.
B Carry - One of the best experts on this subject based on the ideXlab platform.
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Solar System science with esa euclid
Astronomy and Astrophysics, 2018Co-Authors: B CarryAbstract:Context. The ESA Euclid mission has been designed to map the geometry of the dark Universe. Scheduled for launch in 2020, it will conduct a six-year visible and near-infrared imaging and spectroscopic survey over 15 000 deg 2 down to V AB ~ 24.5. Although the survey will avoid ecliptic latitudes below 15°, the survey pattern in repeated sequences of four broadband filters seems well-adapted to detect and characterize Solar System objects (SSOs). Aims. We aim at evaluating the capability of Euclid of discovering SSOs and of measuring their position, apparent magnitude, and spectral energy distribution. We also investigate how the SSO orbits, morphology (activity and multiplicity), physical properties (rotation period, spin orientation, and 3D shape), and surface composition can be determined based on these measurements. Methods. We used the current census of SSOs to extrapolate the total amount of SSOs that will be detectable by Euclid , that is, objects within the survey area and brighter than the limiting magnitude. For each different population of SSO, from neighboring near-Earth asteroids to distant Kuiper-belt objects (KBOs) and including comets, we compared the expected Euclid astrometry, photometry, and spectroscopy with the SSO properties to estimate how Euclid will constrain the SSOs dynamical, physical, and compositional properties. Results. With the current survey design, about 150 000 SSOs, mainly from the asteroid main-belt, should be observable by Euclid . These objects will all have high inclination, which is a difference to many SSO surveys that focus on the ecliptic plane. Euclid may be able to discover several 10 4 SSOs, in particular, distant KBOs at high declination. The Euclid observations will consist of a suite of four sequences of four measurements and will refine the spectral classification of SSOs by extending the spectral coverage provided by Gaia and the LSST, for instance, to 2 microns. Combined with sparse photometry such as measured by Gaia and the LSST, the time-resolved photometry will contribute to determining the SSO rotation period, spin orientation, and 3D shape model. The sharp and stable point-spread function of Euclid will also allow us to resolve binary Systems in the Kuiper belt and detect activity around Centaurs. Conclusions. The depth of the Euclid survey ( V AB ~ 24.5), its spectral coverage (0.5 to 2.0 μ m), and its observation cadence has great potential for Solar System research. A dedicated processing for SSOs is being set up within the Euclid consortium to produce astrometry catalogs, multicolor and time-resolved photometry, and spectral classification of some 10 5 SSOs, which will be delivered as Legacy Science.
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Solar System evolution from compositional mapping of the asteroid belt
Nature, 2014Co-Authors: Francesca E Demeo, B CarryAbstract:Advances in the discovery and characterization of asteroids over the past decade have revealed an unanticipated underlying structure that points to a dramatic early history of the inner Solar System. The asteroids in the main asteroid belt have been discovered to be more compositionally diverse with size and distance from the Sun than had previously been known. This implies substantial mixing through processes such as planetary migration and the subsequent dynamical processes.
Sune G Nielsen - One of the best experts on this subject based on the ideXlab platform.
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early accretion of water and volatile elements to the inner Solar System evidence from angrites
Philosophical Transactions of the Royal Society A, 2017Co-Authors: Adam R Sarafian, Sune G Nielsen, Horst R Marschall, Francis M Mccubbin, Erik H Hauri, Thomas J Lapen, Eve L Berger, Glenn A Gaetani, Kevin Righter, Emily SarafianAbstract:Inner Solar System bodies are depleted in volatile elements relative to chondrite meteorites, yet the source(s) and mechanism(s) of volatile-element depletion and/or enrichment are poorly constrain...
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early accretion of water in the inner Solar System from a carbonaceous chondrite like source
Science, 2014Co-Authors: Adam R Sarafian, Sune G Nielsen, Horst R Marschall, Francis M Mccubbin, Brian D MonteleoneAbstract:Determining the origin of water and the timing of its accretion within the inner Solar System is important for understanding the dynamics of planet formation. The timing of water accretion to the inner Solar System also has implications for how and when life emerged on Earth. We report in situ measurements of the hydrogen isotopic composition of the mineral apatite in eucrite meteorites, whose parent body is the main-belt asteroid 4 Vesta. These measurements sample one of the oldest hydrogen reservoirs in the Solar System and show that Vesta contains the same hydrogen isotopic composition as that of carbonaceous chondrites. Taking into account the old ages of eucrite meteorites and their similarity to Earth’s isotopic ratios of hydrogen, carbon, and nitrogen, we demonstrate that these volatiles could have been added early to Earth, rather than gained during a late accretion event.
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large thallium isotopic variations in iron meteorites and evidence for lead 205 in the early Solar System
Geochimica et Cosmochimica Acta, 2006Co-Authors: Sune G Nielsen, Mark Rehkamper, Alex N HallidayAbstract:Abstract Lead-205 decays to 205Tl with a half-life of 15 Myr and should have been present in the early Solar System according to astrophysical models. However, despite numerous attempts, Tl isotopic measurements of meteorites have been unable to demonstrate convincingly its former presence. Here, we report large (∼5‰) variations in Tl isotope composition in metal and troilite fragments from a range of iron meteorites that were determined at high precision using multiple collector inductively coupled plasma mass spectrometry. The Tl isotopic compositions of seven metal samples of the IAB iron meteorites Toluca and Canyon Diablo define a correlation with 204Pb/203Tl. When interpreted as an isochron, this corresponds to an initial 205Pb/204Pb ratio of (7.4 ± 1.0) × 10−5. Alternative explanations for the correlation, such as mixing of variably mass-fractionated meteorite components or terrestrial contamination are harder to reconcile with independent constraints. However, troilite nodules from Toluca and Canyon Diablo contain Tl that is significantly less radiogenic than co-existing metal with isotope compositions that are variable and decoupled from 204Pb/203Tl. These effects are similar to those recently reported by others for Fe and Ni isotopes in iron meteorite sulfides and appear to be the result of kinetic stable isotope fractionation during diffusion. Though it cannot conclusively be shown that the metal fragments are unaffected by the secondary processes that disturbed the troilites, mass balance modeling indicates that the alteration of the troilites is unlikely to have significantly affected the Tl isotope compositions of the co-existing metals. It is therefore reasonable to conclude that the IAB metal isochron is a product of the in situ decay of 205Pb. If the I–Xe ages of IAB silicate inclusions record the same event as the 205Pb–205Tl chronometer then crystallization of the IAB metal was probably completed between 10 and 20 Myr after the condensation of the first solids. This implies an initial Solar System 205Pb/204Pb of (1.0–2.1) × 10−4, which is in excellent agreement with recently published astrophysical predictions. Similar calculations yield an initial Solar System Tl isotope composition of e205Tl = −2.8 ± 1.7. The Tl isotopic composition and concentration of the silicate Earth depends critically on the timing and mechanism of core formation and Earth’s volatile element depletion history. Modeling of the Earth’s accretion and core formation using the calculated initial Solar System Tl isotope composition and 205Pb/204Pb, however, does not yield reasonable results for the silicate Earth unless either the Earth lost Tl and Pb late in its accretion history or the core contains much higher concentrations of Pb and Tl than are found in iron meteorites.
Emily Sarafian - One of the best experts on this subject based on the ideXlab platform.
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early accretion of water and volatile elements to the inner Solar System evidence from angrites
Philosophical Transactions of the Royal Society A, 2017Co-Authors: Adam R Sarafian, Sune G Nielsen, Horst R Marschall, Francis M Mccubbin, Erik H Hauri, Thomas J Lapen, Eve L Berger, Glenn A Gaetani, Kevin Righter, Emily SarafianAbstract:Inner Solar System bodies are depleted in volatile elements relative to chondrite meteorites, yet the source(s) and mechanism(s) of volatile-element depletion and/or enrichment are poorly constrain...
Matthieu Gounelle - One of the best experts on this subject based on the ideXlab platform.
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an early Solar System magnetic field recorded in cm chondrites
Earth and Planetary Science Letters, 2015Co-Authors: C Cournede, Matthieu Gounelle, Jerome Gattacceca, P Rochette, Benjamin P Weiss, B ZandaAbstract:Abstract We present a paleomagnetic study of seven CM carbonaceous chondrites. CM chondrites are believed to be some of the most chemically primitive materials available in our Solar System and may sample the continuum of transitional objects between asteroids and comets formed in the outer Solar System. As such, CM chondrites can help us to understand primordial aspects of the history of the early Solar System including protoplanetary disk and planetesimal magnetism. The ferromagnetic assemblage of CM chondrites is composed of a mixture of primary metallic iron, pyrrhotite, and magnetite. The remanent properties are usually dominated by secondary pyrrhotite. Paleomagnetic analyses using thermal and alternating field demagnetization identified a stable origin-trending component of magnetization in the seven studied CM chondrites. In each meteorite, this component is homogeneous in direction at least at the cm scale and is therefore post-accretional. We interpret this stable component as a pre-terrestrial chemical remanent magnetization acquired during crystallization of magnetite and pyrrhotite during parent body aqueous alteration in a field of at least a few μ T ( 2 ± 1.5 μ T ) . Considering the timescale and intensities of primordial magnetic fields, both internally generated fields from a putative dynamo and external fields, generated in the protoplanetary disk, may have been recorded by CM chondrites. It is presently difficult to discriminate between the two hypotheses. Regardless, CM chondrites likely contain the oldest paleomagnetic record yet identified.
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massive stars and short lived radionuclides in the Solar System
Eas Publications Series, 2011Co-Authors: Matthieu GounelleAbstract:Short-lived radionuclides (SLRs) are radioactive elements (T 1/2 ≺ 200 Myr) which were present in the nascent Solar System and are now extinct. While the initial abundance of SLRs with the longest half-lives (T 1/2 ≻ 3 Myr) is compatible with the expectations of Galactic evolution models, others have a last-minute origin. 7 Be, 10 Be, 36 Cl, and 41 Ca probably originated within the protoplanetary disk from the irradiation of gas and dust by energetic particles accelerated by the protoSun. 26 Al and 60 Fe were probably synthesized by massive stars and added to interstellar gas which will eventually make up the bulk of our Solar System. Identifying the detailed mechanisms of 26 Al and 60 Fe production and mixing will shed a light on the relationship between the Sun formation history and massive stars.
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astronomical oxygen isotopic evidence for supernova enrichment of the Solar System birth environment by propagating star formation
The Astrophysical Journal, 2011Co-Authors: Edward D Young, Matthieu Gounelle, Rachel L Smith, Mark Morris, K M PontoppidanAbstract:New infrared absorption measurements of oxygen isotope ratios in CO gas from individual young stellar objects confirm that the Solar System is anomalously high in its [^(18)O]/[^(17)O] ratio compared with extraSolar oxygen in the Galaxy. We show that this difference in oxygen isotope ratios is best explained by ~1% enrichment of the protoSolar molecular cloud by ejecta from Type II supernovae from a cluster having of order a few hundred stars that predated the Sun by at least 10-20 Myr. The likely source of exogenous oxygen was the explosion of one or more B stars during a process of propagating star formation.
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the origin of short lived radionuclides and the astrophysical environment of Solar System formation
The Astrophysical Journal, 2008Co-Authors: Matthieu Gounelle, Anders MeibomAbstract:Based on early Solar System abundances of short-lived radionuclides (SRs), such as Al-26 (T-1/2 = 0.74 Myr) and Fe-60 (T-1/2 1.5 Myr), it is often asserted that the Sun was born in a large stellar cluster, where a massive star contaminated the protoplanetary disk with freshly nucleosynthesized isotopes from its supernova (SN) explosion. To account for the inferred initial Solar System abundances of short-lived radionuclides, this supernova had to be close (similar to 0.3 pc) to the young (similar to 1 Myr) protoplanetary disk. Here we show that massive star evolution timescales are too long, compared to typical timescales of star formation in embedded clusters, for them to explode as supernovae within the lifetimes of nearby disks. This is especially true in an Orion Nebular Cluster ( ONC) type of setting, where the most massive star will explode as a supernova similar to 5 Myr after the onset of star formation, when nearby disks will have already suffered substantial photoevaporation and/or formed large planetesimals. We quantify the probability for any protoplanetary disk to receive SRs from a nearby supernova at the level observed in the early Solar System. Key constraints on our estimate are: ( 1) SRs have to be injected into a newly formed (<= 1 Myr) disk, ( 2) the disk has to survive UV photoevaporation, and ( 3) the protoplanetary disk must be situated in an enrichment zone permitting SR injection at the Solar System level without disk disruption. The probability of protoplanetary disk contamination by a supernova ejecta is, in the most favorable case, 3 x 10(-3). We propose instead that Fe-60 (and possibly Al-26) was inherited from the interstellar medium.
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irradiation in the early Solar System and the origin of short lived radionuclides
Comptes Rendus Geoscience, 2007Co-Authors: Matthieu Gounelle, Marc Chaussidon, Thierry MontmerleAbstract:The origin of short-lived (T ∼ 1 Myr) radionuclides (SRs) in the early Solar System is a matter of debate. Some short-lived radionuclides had abundances in the Solar protoplanetary disk in excess compared to the expected galactic background ( 7 Be, 10 Be, 26 Al, 36 Cl, 41 Ca and possibly 53 Mn and 60 Fe). These SRs thus either originated from a supernova contamination, or were produced by in situ irradiation of Solar System dust or gas, or by Galactic Cosmic Ray (GCR) trapping in the molecular cloud core progenitor of our Solar System (for 10 Be only). GCR trapping in the molecular cloud core seems to fail to reproduce the initial abundance of 10 Be, because trapping timescales exceed by one order of magnitude the observed core lifetimes. On the other hand, irradiation models can synthesize large quantities of 10 Be and other SRs ( 7 Be, 36 Cl, 26 Al, 41 Ca and 53 Mn). In addition, X-ray observations of young, Solar-like stars provide direct evidence for protoplanetary disk irradiation in a different energy window. The initial abundance of 60 Fe is poorly known, and its presence in the early Solar System might be accounted for galactic abundance rather than by a nearby supernova.
