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Aldo Serenelli - One of the best experts on this subject based on the ideXlab platform.

  • Helioseismic and neutrino data-driven reconstruction of Solar properties
    Monthly Notices of the Royal Astronomical Society, 2018
    Co-Authors: Ningqiang Song, M. C. Gonzalez-garcia, Francesco L. Villante, Núria Vinyoles, Aldo Serenelli
    Abstract:

    In this work we use Bayesian inference to quantitatively reconstruct the Solar properties most relevant to the Solar Composition problem using as inputs the information provided by helioseismic and Solar neutrino data. In particular, we use a Gaussian process to model the functional shape of the opacity uncertainty to gain flexibility and become as free as possible from prejudice in this regard. With these tools we first readdress the statistical significance of the Solar Composition problem. Furthermore, starting from a Composition unbiased set of standard Solar models we are able to statistically select those with Solar chemical Composition and other Solar inputs which better describe the helioseismic and neutrino observations. In particular, we are able to reconstruct the Solar opacity profile in a data driven fashion, independently of any reference opacity tables, obtaining a 4% uncertainty at the base of the convective envelope and 0.8% at the Solar core. When systematic uncertainties are included, results are 7.5% and 2% respectively. In addition we find that the values of most of the other inputs of the standard Solar models required to better describe the helioseismic and neutrino data are in good agreement with those adopted as the standard priors, with the exception of the astrophysical factor $S_{11}$ and the microscopic diffusion rates, for which data suggests a 1% and 30% reduction respectively. As an output of the study we derive the corresponding data driven predictions for the Solar neutrino fluxes.

  • A Quantitative Analysis of the Solar Composition Problem
    Physics Procedia, 2015
    Co-Authors: F.l. Villante, Aldo Serenelli
    Abstract:

    Abstract We perform a quantitative analysis of the Solar Composition problem by using a statistical approach that allows us to combine the information provided by helioseismic and Solar neutrino data in an effective way. We show that the opacity profile of the Sun is well constrained by the Solar observational properties. In the context of a two parameter analysis in which elements are grouped as volatiles (i.e. C, N, O and Ne) and refractories (i.e. Mg, Si, S, Fe), the optimal surface Composition is found by increasing the abundance of volatiles by (45 ± 4) % and that of refractories by (19 ± 3) % with respect to the values provided by Asplund et al., 2009. As an additional result of our analysis, we show that the best fit to the observational data is obtained with values of input parameters of the standard Solar models (radiative opacities, gravitational settling rate, the astrophysical factors S 34 and S 17) that differ at the ∼ 1σ level from those presently adopted.

  • using the standard Solar model to constrain Solar Composition and nuclear reaction s factors
    Physical Review D, 2013
    Co-Authors: Aldo Serenelli, Carlos Penagaray, W C Haxton
    Abstract:

    A. M. S. is partially supported by the European Union International Reintegration No. PIRG-GA-2009-247732, the MICINN Grant No. AYA2011-24704, by the ESF EUROCORES Program EuroGENESIS (MICINN Grant No. EUI2009-04170), by SGR Grants of the Generalitat de Catalunya and by the EU-FEDER funds. C. P.-G. is supported in part by the Spanish MICINN Grants No. FPA-2007-60323 and No. FPA2011-29678, the Generalitat Valenciana Grant No. PROMETEO/2009/116 and the ITN INVISIBLES (Marie Curie Actions, PITN-GA-2011-289442). This work was supported in part by the U.S. DOE under Grants No. DE-SC00046548 (Berkeley) and No. DE-AC02-98CH10886 (LBL). W. H. thanks the INT and GSI for their hospitality while part of this work was done, and the Alexander von Humboldt Foundation for its support.

  • New Solar Composition: the problem with Solar models revisited
    The Astrophysical Journal, 2009
    Co-Authors: Aldo Serenelli, Sarbani Basu, Jason W. Ferguson, Martin Asplund
    Abstract:

    We construct updated Solar models with different sets of Solar abundances, including the most recent determinations by Asplund et al. The latter work predicts a larger (~10%) Solar metallicity compared to previous measurements by the same authors but significantly lower (~25%) than the recommended value from a decade ago by Grevesse & Sauval. We compare the results of our models with determinations of the Solar structure inferred through helioseismology measurements. The model that uses the most recent Solar abundance determinations predicts the base of the Solar convective envelope to be located at R CZ = 0.724 R ☉ and a surface helium mass fraction of Y surf = 0.231. These results are in conflict with helioseismology data (R CZ = 0.713 ± 0.001 R ☉ and Y surf = 0.2485 ± 0.0035) at 5σ and 11σ levels, respectively. Using the new Solar abundances, we calculate the magnitude by which radiative opacities should be modified in order to restore agreement with helioseismology. We find that a maximum change of ~15% at the base of the convective zone is required with a smooth decrease toward the core, where the change needed is ~5%. The required change at the base of the convective envelope is about half the value estimated previously. We also present the Solar neutrino fluxes predicted by the new models. The most important changes brought about by the new Solar abundances are the increase by ~10% in the predicted 13N and 15O fluxes that arise mostly due to the increase in the C and N abundances in the newly determined Solar Composition.

  • Solar neutrinos and the Solar Composition problem
    arXiv: Astrophysics, 2008
    Co-Authors: Carlos Pena-garay, Aldo Serenelli
    Abstract:

    Standard Solar models (SSM) are facing nowadays a new puzzle: the Solar Composition problem. New determinations of Solar metal abundances lead SSM calculations to conflict with helioseismological measurements, showing discrepancies that extend from the convection zone to the Solar core and can not be easily assigned to deficiencies in the modelling of the Solar convection zone. We present updated Solar neutrino fluxes and uncertainties for two SSM with high (old) and low (new) Solar metallicity determinations. The uncertainties in iron and carbon abundances are the largest contribution to the uncertainties of the Solar neutrino fluxes. The uncertainty on the ^14N+p -> ^15O+g rate is the largest of the non-Composition uncertainties to the CNO neutrino fluxes. We propose an independent method to help identify which SSM is the correct one. Present neutrino data can not distinguish the Solar neutrino predictions of both models but ongoing measurements can help to solve the puzzle.

Jonathan I Lunine - One of the best experts on this subject based on the ideXlab platform.

  • Modeling Synthetic Spectra for Transiting ExtraSolar Giant Planets: Detectability of H2S and PH3 with the James Webb Space Telescope
    The Astrophysical Journal, 2017
    Co-Authors: Dong Wang, Yamila Miguel, Jonathan I Lunine
    Abstract:

    JWST$'$s large aperture and wide wavelength coverage will enable it to collect the highest quality transit spectra observed so far. For exoplanetary atmospheres we expect to retrieve the abundance of the most abundant molecules, such as H$_2$O, CO, and CH$_4$. Other molecules, such as H$_2$S and PH$_3$, have been observed in Jupiter and Saturn but their chemistry and detectability in strongly irradiated planets is highly unknown. In this paper, we make the first effort to study their spectral features in Solar Composition atmospheres, and evaluate their detectability with JWST. We model the chemistry of phosphorus and sulfur in Solar Composition atmospheres. Our model includes the effect of vertical transport. Photochemistry effects are not included in our calculations. Using the abundance profiles, we model the JWST transmission and emission spectra for K=6.8 G-type star and for planets with cloud-free Solar Composition atmospheres. We find PH$_3$ is detectable at 3 sigma from transmission spectra of the simulated atmosphere with $T_{\rm eq}$ $ $ 1500K using the NIRCam LW grism F322W2 mode with a total observing time of 24.0 hrs. Our results specifically highlight the importance of including H$_2$S for future abundances retrieval with JWST. The presence of clouds and hazes challenges the detections of PH$_3$ and H$_2$S, but H$_2$S features are still expected to be present in the emission spectra.

  • carbon rich planet formation in a Solar Composition disk
    The Astrophysical Journal, 2014
    Co-Authors: Mohamad Alidib, O Mousis, Jeanmarc Petit, Jonathan I Lunine
    Abstract:

    The C to O ratio is a crucial determinant of the chemical properties of planets. The recent observation of WASP 12b, a giant planet with a C/O value larger than that estimated for its host star, poses a conundrum for understanding the origin of this elemental ratio in any given planetary system. In this paper, we propose a mechanism for enhancing the value of C/O in the disk through the transport and distribution of volatiles. We construct a model that computes the abundances of major C- and O-bearing volatiles under the influence of gas drag, sublimation, vapor diffusion, condensation, and coagulation in a multi-iceline 1+1D protoplanetary disk. We find a gradual depletion in water and carbon monoxide vapors inside the water's iceline, with carbon monoxide depleting slower than water. This effect increases the gaseous C/O and decreases the C/H ratio in this region to values similar to those found in WASP 12b's day side atmosphere. Giant planets whose envelopes were accreted inside the water's iceline should then display C/O values larger than those of their parent stars, making them members of the class of so-called carbon-rich planets.

  • Oxygen and Other Volatiles in the Giant Planets and their Satellites
    Reviews in Mineralogy & Geochemistry, 2008
    Co-Authors: Michael H. Wong, Jonathan I Lunine, Sushil K. Atreya, Torrence V. Johnson, Paul R. Mahaffy, Tobias Owen, Thérèse Encrenaz
    Abstract:

    Giant planet atmospheric Composition and satellite densities provide insights into protoplanetary disk conditions. Abundances of condensable species and noble gases in wellmixed atmospheres can distinguish among several giant planet formation scenarios, and satellite densities are fi rst order measurements of ice:rock ratios. Recent work on protoSolar abundances, relying on three-dimensional spectroscopic modeling of the Solar photosphere, provides the framework for the interpretation of measurements. Model densities of protoplanetary disk condensates are shown as a function of carbon partitioning between CO, CH4 and organics. Comparison with observed satellite densities shows that Saturn’s icy satellites are inconsistent with Solar Composition, and must either have formed in a water-rich environment or have suffered a complex collisional history. The larger satellites of the giant planets are consistent with Solar Composition, with densities that speak of variation in the partitioning of carbon.

Jorge Melendez - One of the best experts on this subject based on the ideXlab platform.

  • the peculiar Solar Composition and its possible relation to planet formation
    The Astrophysical Journal, 2009
    Co-Authors: Martin Asplund, Jorge Melendez, Bengt Gustafsson, David Yong
    Abstract:

    We have conducted a differential elemental abundance analysis of unprecedented accuracy (~0.01 dex) of the Sun relative to 11 Solar twins from the Hipparcos catalog and 10 Solar analogs from planet searches. We find that the Sun shows a characteristic signature with a 20% depletion of refractory elements relative to the volatile elements in comparison with the Solar twins. The abundance differences correlate strongly with the condensation temperatures of the elements. This peculiarity also holds in comparisons with Solar analogs known to have close-in giant planets while the majority of Solar analogs found not to have such giant planets in radial velocity monitoring show the Solar abundance pattern. We discuss various explanations for this peculiarity, including the possibility that the differences in abundance patterns are related to the formation of planetary systems like our own, in particular to the existence of terrestrial planets.

David Yong - One of the best experts on this subject based on the ideXlab platform.

  • the peculiar Solar Composition and its possible relation to planet formation
    The Astrophysical Journal, 2009
    Co-Authors: Martin Asplund, Jorge Melendez, Bengt Gustafsson, David Yong
    Abstract:

    We have conducted a differential elemental abundance analysis of unprecedented accuracy (~0.01 dex) of the Sun relative to 11 Solar twins from the Hipparcos catalog and 10 Solar analogs from planet searches. We find that the Sun shows a characteristic signature with a 20% depletion of refractory elements relative to the volatile elements in comparison with the Solar twins. The abundance differences correlate strongly with the condensation temperatures of the elements. This peculiarity also holds in comparisons with Solar analogs known to have close-in giant planets while the majority of Solar analogs found not to have such giant planets in radial velocity monitoring show the Solar abundance pattern. We discuss various explanations for this peculiarity, including the possibility that the differences in abundance patterns are related to the formation of planetary systems like our own, in particular to the existence of terrestrial planets.

Martin Asplund - One of the best experts on this subject based on the ideXlab platform.

  • The New Solar Composition and the Solar Metallicity
    The Sun the Solar Wind and the Heliosphere, 2010
    Co-Authors: N. Grevesse, A J Sauval, Martin Asplund, Pat Scott
    Abstract:

    We review the current status of our knowledge of the chemical Composition of the sun and present a redetermination of the Solar abundances of all available elements. These new results have very recently been published by Asplund et al. (2009). The basic ingredients of this work, the main results and their implications are discussed.

  • New Solar Composition: the problem with Solar models revisited
    The Astrophysical Journal, 2009
    Co-Authors: Aldo Serenelli, Sarbani Basu, Jason W. Ferguson, Martin Asplund
    Abstract:

    We construct updated Solar models with different sets of Solar abundances, including the most recent determinations by Asplund et al. The latter work predicts a larger (~10%) Solar metallicity compared to previous measurements by the same authors but significantly lower (~25%) than the recommended value from a decade ago by Grevesse & Sauval. We compare the results of our models with determinations of the Solar structure inferred through helioseismology measurements. The model that uses the most recent Solar abundance determinations predicts the base of the Solar convective envelope to be located at R CZ = 0.724 R ☉ and a surface helium mass fraction of Y surf = 0.231. These results are in conflict with helioseismology data (R CZ = 0.713 ± 0.001 R ☉ and Y surf = 0.2485 ± 0.0035) at 5σ and 11σ levels, respectively. Using the new Solar abundances, we calculate the magnitude by which radiative opacities should be modified in order to restore agreement with helioseismology. We find that a maximum change of ~15% at the base of the convective zone is required with a smooth decrease toward the core, where the change needed is ~5%. The required change at the base of the convective envelope is about half the value estimated previously. We also present the Solar neutrino fluxes predicted by the new models. The most important changes brought about by the new Solar abundances are the increase by ~10% in the predicted 13N and 15O fluxes that arise mostly due to the increase in the C and N abundances in the newly determined Solar Composition.

  • the peculiar Solar Composition and its possible relation to planet formation
    The Astrophysical Journal, 2009
    Co-Authors: Martin Asplund, Jorge Melendez, Bengt Gustafsson, David Yong
    Abstract:

    We have conducted a differential elemental abundance analysis of unprecedented accuracy (~0.01 dex) of the Sun relative to 11 Solar twins from the Hipparcos catalog and 10 Solar analogs from planet searches. We find that the Sun shows a characteristic signature with a 20% depletion of refractory elements relative to the volatile elements in comparison with the Solar twins. The abundance differences correlate strongly with the condensation temperatures of the elements. This peculiarity also holds in comparisons with Solar analogs known to have close-in giant planets while the majority of Solar analogs found not to have such giant planets in radial velocity monitoring show the Solar abundance pattern. We discuss various explanations for this peculiarity, including the possibility that the differences in abundance patterns are related to the formation of planetary systems like our own, in particular to the existence of terrestrial planets.