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Your search keyword '"Cabedo, V."' showing total 2 results
Start Over Author "Cabedo, V." Topic astrophysics - earth and planetary astrophysics
2 results on '"Cabedo, V."'

1. Reactivity of chondritic meteorites under H2-rich atmospheres: Formation of H2S

Author

Cabedo, V., Pareras, G., Allitt, J., Rimola, A., Llorca, J., Yiu, H. H. P., and McCoustra, M. R. S.

Subjects
Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics, Physics - Geophysics
Abstract

Current models of chemical evolution during star and planetary formation rely on the presence of dust grains to act as a third body. However, they generally ignore the reactivity of the dust grains themselves. Dust grains present in the protoplanetary phase will evolve as the solar system forms and, after protoplanets have appeared, they will be constantly delivered to their surfaces in the form of large aggregates or meteorites. Chondritic meteorites are mostly unaltered samples of the dust present in the first stages of the Solar System formation, that still arrive nowadays to the surface of Earth and allow us to study the properties of the materials forming the early Solar System. These materials contain, amongst others, transition metals that can potentially act as catalysts, as well as other phases that can potentially react in different astrophysical conditions, such as FeS. In this work, we present the reactivity of chondritic meteorites under \hydrogen-rich atmospheres, particularly towards the reduction of FeS for the formation of H2S and metallic Fe during the early phases of the planetary formation. We present the obtained results on the reaction rates and the percentage of FeS available to react in the materials. Additionally, we include a computational study of the reaction mechanism and the energetics. Finally, we discuss the implications of an early formation of H2S in planetary surfaces., Comment: Approved for publication in MNRAS

Published
2024

2. Constraints on the structure and seasonal variations of Triton's atmosphere from the 5 October 2017 stellar occultation and previous observations

Author

Oliveira, J. Marques, Sicardy, B., Gomes-Júnior, A. R., Ortiz, J. L., Strobel, D. F., Bertrand, T., Forget, F., Lellouch, E., Desmars, J., Bérard, D., Doressoundiram, A., Lecacheux, J., Leiva, R., Meza, E., Roques, F., Souami, D., Widemann, T., Santos-Sanz, P., Morales, N., Duffard, R., Fernández-Valenzuela, E., Castro-Tirado, A. J., Braga-Ribas, F., Morgado, B. E., Assafin, M., Camargo, J. I. B., Vieira-Martins, R., Benedetti-Rossi, G., Santos-Filho, S., Banda-Huarca, M. V., Quispe-Huaynasi, F., Pereira, C. L., Rommel, F. L., Margoti, G., Dias-Oliveira, A., Colas, F., Berthier, J., Renner, S., Hueso, R., Pérez-Hoyos, S., Sánchez-Lavega, A., Rojas, J. F., Beisker, W., Kretlow, M., Herald, D., Gault, D., Bath, K. -L., Bode, H. -J., Bredner, E., Guhl, K., Haymes, T. V., Hummel, E., Kattentidt, B., Klös, O., Pratt, A., Thome, B., Avdellidou, C., Gazeas, K., Karampotsiou, E., Tzouganatos, L., Kardasis, E., Christou, A. A., Xilouris, E. M., Alikakos, I., Gourzelas, A., Liakos, A., Charmandaris, V., Jelínek, M., Štrobl, J., Eberle, A., Rapp, K., Gährken, B., Klemt, B., Kowollik, S., Bitzer, R., Miller, M., Herzogenrath, G., Frangenberg, D., Brandis, L., Pütz, I., Perdelwitz, V., Piehler, G. M., Riepe, P., von Poschinger, K., Baruffetti, P., Cenadelli, D., Christille, J. -M., Ciabattari, F., Di Luca, R., Alboresi, D., Leto, G., Sanchez, R. Zanmar, Bruno, P., Occhipinti, G., Morrone, L., Cupolino, L., Noschese, A., Vecchione, A., Scalia, C., Savio, R. Lo, Giardina, G., Kamoun, S., Barbosa, R., Behrend, R., Spano, M., Bouchet, E., Cottier, M., Falco, L., Gallego, S., Tortorelli, L., Sposetti, S., Sussenbach, J., Abbeel, F. Van Den, André, P., Llibre, M., Pailler, F., Ardissone, J., Boutet, M., Sanchez, J., Bretton, M., Cailleau, A., Pic, V., Granier, L., Chauvet, R., Conjat, M., Dauvergne, J. L., Dechambre, O., Delay, P., Delcroix, M., Rousselot, L., Ferreira, J., Machado, P., Tanga, P., Rivet, J. -P., Frappa, E., Irzyk, M., Jabet, F., Kaschinski, M., Klotz, A., Rieugnie, Y., Klotz, A. N., Labrevoir, O., Lavandier, D., Walliang, D., Leroy, A., Bouley, S., Lisciandra, S., Coliac, J. -F., Metz, F., Erpelding, D., Nougayrède, P., Midavaine, T., Miniou, M., Moindrot, S., Morel, P., Reginato, B., Reginato, E., Rudelle, J., Tregon, B., Tanguy, R., David, J., Thuillot, W., Hestroffer, D., Vaudescal, G., Aissa, D. Baba, Grigahcene, Z., Briggs, D., Broadbent, S., Denyer, P., Haigh, N. J., Quinn, N., Thurston, G., Fossey, S. J., Arena, C., Jennings, M., Talbot, J., Alonso, S., Reche, A. Román, Casanova, V., Briggs, E., Iglesias-Marzoa, R., Ibáñez, J. Abril, Martín, M. C. Díaz, González, H., García, J. L. Maestre, Marchant, J., Ordonez-Etxeberria, I., Martorell, P., Salamero, J., Organero, F., Ana, L., Fonseca, F., Peris, V., Brevia, O., Selva, A., Perello, C., Cabedo, V., Gonçalves, R., Ferreira, M., Dias, F. Marques, Daassou, A., Barkaoui, K., Benkhaldoun, Z., Guennoun, M., Chouqar, J., Jehin, E., Rinner, C., Lloyd, J., Moutamid, M. El, Lamarche, C., Pollock, J. T., Caton, D. B., Kouprianov, V., Timerson, B. W., Blanchard, G., Payet, B., Peyrot, A., Teng-Chuen-Yu, J. -P., Françoise, J., Mondon, B., Payet, T., Boissel, C., Castets, M., Hubbard, W. B., Hill, R., Reitsema, H. J., Mousis, O., Ball, L., Neilsen, G., Hutcheon, S., Lay, K., Anderson, P., Moy, M., Jonsen, M., Pink, I., Walters, R., and Downs, B.

Subjects
Astrophysics - Earth and Planetary Astrophysics
Abstract

A stellar occultation by Neptune's main satellite, Triton, was observed on 5 October 2017 from Europe, North Africa, and the USA. We derived 90 light curves from this event, 42 of which yielded a central flash detection. We aimed at constraining Triton's atmospheric structure and the seasonal variations of its atmospheric pressure since the Voyager 2 epoch (1989). We also derived the shape of the lower atmosphere from central flash analysis. We used Abel inversions and direct ray-tracing code to provide the density, pressure, and temperature profiles in the altitude range $\sim$8 km to $\sim$190 km, corresponding to pressure levels from 9 {\mu}bar down to a few nanobars. Results. (i) A pressure of 1.18$\pm$0.03 {\mu}bar is found at a reference radius of 1400 km (47 km altitude). (ii) A new analysis of the Voyager 2 radio science occultation shows that this is consistent with an extrapolation of pressure down to the surface pressure obtained in 1989. (iii) A survey of occultations obtained between 1989 and 2017 suggests that an enhancement in surface pressure as reported during the 1990s might be real, but debatable, due to very few high S/N light curves and data accessible for reanalysis. The volatile transport model analysed supports a moderate increase in surface pressure, with a maximum value around 2005-2015 no higher than 23 {\mu}bar. The pressures observed in 1995-1997 and 2017 appear mutually inconsistent with the volatile transport model presented here. (iv) The central flash structure does not show evidence of an atmospheric distortion. We find an upper limit of 0.0011 for the apparent oblateness of the atmosphere near the 8 km altitude., Comment: 52 pages, 26 figures in the main paper, 2 figures in appendix B, 9 figures in appendix C, 1 long table over 5 pages

Published
2022
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