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Your search keyword '"Kramm, R."' showing total 2 results
Start Over Author "Kramm, R." Topic astrophysics::cosmology and extragalactic astrophysics
2 results on '"Kramm, R."'

1. Rotating dust particles in the coma of comet 67P/Churyumov-Gerasimenko

Author

A'Hearn, M. F., Wenzel, K. P., Sierks, H., Guettler, C., Marzari, F., Rickman, H., Kueppers, M., Cremonese, G., Naletto, G., Keller, H. U., Michalik, H., Debei, S., Lara, L., Rotundi, A., Bodewits, D., Della Corte, V., Barbieri, C., Vincent, J. B., Agarwal, J., Lazzarin, M., Sabau, L., Barucci, M. A., Ivanovski, S. L., Thomas, Nicolas, Jorda, L., Bertini, I., Lopez-Moreno, J. J., Rodrigo, R., Tubiana, C., Lamy, P. L., Davidsson, B., Hviid, S. F., Kramm, R., De Cecco, M., Knollenberg, J., Bertaux, J. L., Koschny, D., Kuehrt, E., Oklay, N., Fornasier, S., Gutierrez, P., Zakharov, V., Fulle, M., Ip, W., Groussin, O., and Da Deppo, V.

Subjects
13. Climate action, 530 Physics, 520 Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Context. During September and October 2014, the OSIRIS cameras onboard the ESA Rosetta mission detected millions of single particles. Many of these dust particles appear as long tracks (due to both the dust proper motion and the spacecraft motion during the exposure time) with a clear brightness periodicity. Aims. We interpret the observed periodic features as a rotational and translational motion of aspherical dust grains. Methods. By counting the peaks of each track, we obtained statistics of a rotation frequency. We compared these results with the rotational frequency predicted by a model of aspherical dust grain dynamics in a model gas flow. By testing many possible sets of physical conditions and grain characteristics, we constrained the rotational properties of dust grains. Results. We analyzed on the motion of rotating aspherical dust grains with different cross sections in flow conditions corresponding to the coma of 67P/Churyumov-Gerasimenko qualitatively and quantitatively. Based on the OSIRIS observations, we constrain the possible physical parameters of the grains.

2. Evolution of the dust size distribution of comet 67P/Churymov–Gerasimenko from 2.2 au to Perihelion

Author

Rotundi, A., Ortiz, J. L., Mennella, V., Palomba, E., Rickman, H., Bertaux, J.-L., Oklay, N., Altobelli, N., Knollenberg, J., Palumbo, P., Mottola, S., Giovane, F., Grün, E., Küppers, M., Kramm, R., Güttler, C., Barbieri, C., Lamy, P. L., Cremonese, G., Leese, M. R., A’Hearn, M. F., Kührt, E., Bertini, I., Thomas, Nicolas, Fulle, M., Zakharov, V., Lazzarin, M., Esposito, F., Rietmeijer, F. J. M., Barucci, M. A., Sierks, H., Agarwal, J., Davidsson, B., Morales, R., Colangeli, L., Accolla, M., Mazzotta Epifani, E., Molina, A., Keller, H. U., Weissman, P., Green, S. F., Rodrigo, R., De Cecco, M., López-Moreno, J. J., Lara, L., Crifo, J.-F., Ivanovski, S. L., Herranz, M. L., Cosi, M., Tubiana, C., Bussoletti, E., Moreno, F., Marzari, F., Zarnecki, J. C., Jorda, L., Fornasier, S., Groussin, O., Ip, W., Hviid, S. F., Ferrari, M., Vincent, J.-B., Gustafson, B., Jerónimo, J. M., Debei, S., McDonnell, J. A. M., Della Corte, V., Sordini, R., López-Jiménez, A. C., Koschny, D., Da Deppo, V., Naletto, G., Wenzel, K.-P., Lucarelli, F., Perrin, J.-M., Bodewits, D., Gutierrez, P., and Rodríguez, J.

Subjects
13. Climate action, 530 Physics, 520 Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 620 Engineering, Astrophysics::Galaxy Astrophysics
Abstract

The Rosetta probe, orbiting Jupiter-family comet 67P/Churyumov–Gerasimenko, has been detecting individual dust particles of mass larger than 10−10 kg by means of the GIADA dust collector and the OSIRIS Wide Angle Camera and Narrow Angle Camera since 2014 August and will continue until 2016 September. Detections of single dust particles allow us to estimate the anisotropic dust flux from 67P, infer the dust loss rate and size distribution at the surface of the sunlit nucleus, and see whether the dust size distribution of 67P evolves in time. The velocity of the Rosetta orbiter, relative to 67P, is much lower than the dust velocity measured by GIADA, thus dust counts when GIADA is nadir-pointing will directly provide the dust flux. In OSIRIS observations, the dust flux is derived from the measurement of the dust space density close to the spacecraft. Under the assumption of radial expansion of the dust, observations in the nadir direction provide the distance of the particles by measuring their trail length, with a parallax baseline determined by the motion of the spacecraft. The dust size distribution at sizes >1 mm observed by OSIRIS is consistent with a differential power index of −4, which was derived from models of 67P's trail. At sizes

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