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Start Over Author "Tzou, C. Y." Publisher max planck inst sonnensyst forsch, justus von liebig weg 3, d-37077 gottingen, germany.
10 results on '"Tzou, C. Y."'

1. Ion chemistry in the coma of comet 67P near perihelion

Author

Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., Wurz, P., Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., and Wurz, P.

Abstract

The coma and the comet-solar wind interaction of comet 67P/Churyumov-Gerasimenko changed dramatically from the initial Rosetta spacecraft encounter in 2014 August through perihelion in 2015 August. Just before equinox (at 1.6 au from the Sun), the solar wind signal disappeared and two regions of different cometary ion characteristics were observed. These 'outer' and 'inner' regions have cometary ion characteristics similar to outside and inside the ion pileup region observed during the Giotto approach to comet 1P/Halley. Rosetta/Double-Focusing Mass Spectrometer ion mass spectrometer observations are used here to investigate the H3O+/H2O+ ratio in the outer and inner regions at 67P/Churyumov-Gerasimenko. The H3O+/H2O+ ratio and the H3O+ signal are observed to increase in the transition from the outer to the inner region and the H3O+ signal appears to be weakly correlated with cometary ion energy. These ion composition changes are similar to the ones observed during the 1P/Halley flyby. Modelling is used to determine the importance of neutral composition and transport of neutrals and ions away from the nucleus. This modelling demonstrates that changes in the H3O+/H2O+ ratio appear to be driven largely by transport properties and only weakly by neutral composition in the coma.

Published
2016
Full Text
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2. The 2016 Feb 19 outburst of comet 67P/CG : an ESA Rosetta multi-instrument study

Author

Grun, E., Agarwal, J., Altobelli, N., Altwegg, K., Bentley, M. S., Biver, N., Della Corte, V., Edberg, Niklas J. T., Feldman, P. D., Galand, M., Geiger, B., Goetz, C., Grieger, B., Guettler, C., Henri, P., Hofstadter, M., Horanyi, M., Jehin, E., Krueger, H., Lee, S., Mannel, T., Morales, E., Mousis, O., Mueller, M., Opitom, C., Rotundi, A., Schmied, R., Schmidt, F., Sierks, H., Snodgrass, C., Soja, R. H., Sommer, M., Srama, R., Tzou, C. -Y, Vincent, J. -B, Yanamandra-Fisher, P., A'Hearn, M. F., Eriksson, Anders, Barbieri, C., Barucci, M. A., Bertaux, J. -L, Bertini, I., Burch, J., Colangeli, L., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Deller, J., Feaga, L. M., Ferrari, M., Fornasier, S., Fulle, M., Gicquel, A., Gillon, M., Green, S. F., Groussin, O., Gutierrez, P. J., Hofmann, M., Hviid, S. F., Ip, W. -H, Ivanovski, S., Jorda, L., Keller, H. U., Knight, M. M., Knollenberg, J., Koschny, D., Kramm, J. -R, Kuehrt, E., Kuppers, M., Lamy, P. L., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Manfroid, J., Epifani, E. Mazzotta, Marzari, F., Naletto, G., Oklay, N., Palumbo, P., Parker, J. Wm., Rickman, Hans, Rodrigo, R., Rodriguez, J., Schindhelm, E., Shi, X., Sordini, R., Steffl, A. J., Stern, S. A., Thomas, N., Tubiana, C., Weaver, H. A., Weissman, P., Zakharov, V. V., Grun, E., Agarwal, J., Altobelli, N., Altwegg, K., Bentley, M. S., Biver, N., Della Corte, V., Edberg, Niklas J. T., Feldman, P. D., Galand, M., Geiger, B., Goetz, C., Grieger, B., Guettler, C., Henri, P., Hofstadter, M., Horanyi, M., Jehin, E., Krueger, H., Lee, S., Mannel, T., Morales, E., Mousis, O., Mueller, M., Opitom, C., Rotundi, A., Schmied, R., Schmidt, F., Sierks, H., Snodgrass, C., Soja, R. H., Sommer, M., Srama, R., Tzou, C. -Y, Vincent, J. -B, Yanamandra-Fisher, P., A'Hearn, M. F., Eriksson, Anders, Barbieri, C., Barucci, M. A., Bertaux, J. -L, Bertini, I., Burch, J., Colangeli, L., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Deller, J., Feaga, L. M., Ferrari, M., Fornasier, S., Fulle, M., Gicquel, A., Gillon, M., Green, S. F., Groussin, O., Gutierrez, P. J., Hofmann, M., Hviid, S. F., Ip, W. -H, Ivanovski, S., Jorda, L., Keller, H. U., Knight, M. M., Knollenberg, J., Koschny, D., Kramm, J. -R, Kuehrt, E., Kuppers, M., Lamy, P. L., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Manfroid, J., Epifani, E. Mazzotta, Marzari, F., Naletto, G., Oklay, N., Palumbo, P., Parker, J. Wm., Rickman, Hans, Rodrigo, R., Rodriguez, J., Schindhelm, E., Shi, X., Sordini, R., Steffl, A. J., Stern, S. A., Thomas, N., Tubiana, C., Weaver, H. A., Weissman, P., and Zakharov, V. V.

Abstract

On 2016 Feb 19, nine Rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus of comet 67P/Churyumov-Gerasimenko. Among these instruments were cameras and spectrometers ranging from UV over visible to microwave wavelengths, in situ gas, dust and plasma instruments, and one dust collector. At 09: 40 a dust cloud developed at the edge of an image in the shadowed region of the nucleus. Over the next two hours the instruments recorded a signature of the outburst that significantly exceeded the background. The enhancement ranged from 50 per cent of the neutral gas density at Rosetta to factors > 100 of the brightness of the coma near the nucleus. Dust related phenomena (dust counts or brightness due to illuminated dust) showed the strongest enhancements (factors > 10). However, even the electron density at Rosetta increased by a factor 3 and consequently the spacecraft potential changed from similar to-16 V to -20 V during the outburst. A clear sequence of events was observed at the distance of Rosetta ( 34 km from the nucleus): within 15 min the Star Tracker camera detected fast particles (similar to 25 m s(-1)) while 100 mu m radius particles were detected by the GIADA dust instrument similar to 1 h later at a speed of 6 m s(-1). The slowest were individual mm to cm sized grains observed by the OSIRIS cameras. Although the outburst originated just outside the FOV of the instruments, the source region and the magnitude of the outburst could be determined.

Published
2016
Full Text
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3. Ion chemistry in the coma of comet 67P near perihelion

Author

Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., Wurz, P., Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., and Wurz, P.

Abstract

The coma and the comet-solar wind interaction of comet 67P/Churyumov-Gerasimenko changed dramatically from the initial Rosetta spacecraft encounter in 2014 August through perihelion in 2015 August. Just before equinox (at 1.6 au from the Sun), the solar wind signal disappeared and two regions of different cometary ion characteristics were observed. These 'outer' and 'inner' regions have cometary ion characteristics similar to outside and inside the ion pileup region observed during the Giotto approach to comet 1P/Halley. Rosetta/Double-Focusing Mass Spectrometer ion mass spectrometer observations are used here to investigate the H3O+/H2O+ ratio in the outer and inner regions at 67P/Churyumov-Gerasimenko. The H3O+/H2O+ ratio and the H3O+ signal are observed to increase in the transition from the outer to the inner region and the H3O+ signal appears to be weakly correlated with cometary ion energy. These ion composition changes are similar to the ones observed during the 1P/Halley flyby. Modelling is used to determine the importance of neutral composition and transport of neutrals and ions away from the nucleus. This modelling demonstrates that changes in the H3O+/H2O+ ratio appear to be driven largely by transport properties and only weakly by neutral composition in the coma.

Published
2016
Full Text
View/download PDF

4. The 2016 Feb 19 outburst of comet 67P/CG : an ESA Rosetta multi-instrument study

Author

Grun, E., Agarwal, J., Altobelli, N., Altwegg, K., Bentley, M. S., Biver, N., Della Corte, V., Edberg, Niklas J. T., Feldman, P. D., Galand, M., Geiger, B., Goetz, C., Grieger, B., Guettler, C., Henri, P., Hofstadter, M., Horanyi, M., Jehin, E., Krueger, H., Lee, S., Mannel, T., Morales, E., Mousis, O., Mueller, M., Opitom, C., Rotundi, A., Schmied, R., Schmidt, F., Sierks, H., Snodgrass, C., Soja, R. H., Sommer, M., Srama, R., Tzou, C. -Y, Vincent, J. -B, Yanamandra-Fisher, P., A'Hearn, M. F., Eriksson, Anders, Barbieri, C., Barucci, M. A., Bertaux, J. -L, Bertini, I., Burch, J., Colangeli, L., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Deller, J., Feaga, L. M., Ferrari, M., Fornasier, S., Fulle, M., Gicquel, A., Gillon, M., Green, S. F., Groussin, O., Gutierrez, P. J., Hofmann, M., Hviid, S. F., Ip, W. -H, Ivanovski, S., Jorda, L., Keller, H. U., Knight, M. M., Knollenberg, J., Koschny, D., Kramm, J. -R, Kuehrt, E., Kuppers, M., Lamy, P. L., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Manfroid, J., Epifani, E. Mazzotta, Marzari, F., Naletto, G., Oklay, N., Palumbo, P., Parker, J. Wm., Rickman, Hans, Rodrigo, R., Rodriguez, J., Schindhelm, E., Shi, X., Sordini, R., Steffl, A. J., Stern, S. A., Thomas, N., Tubiana, C., Weaver, H. A., Weissman, P., Zakharov, V. V., Grun, E., Agarwal, J., Altobelli, N., Altwegg, K., Bentley, M. S., Biver, N., Della Corte, V., Edberg, Niklas J. T., Feldman, P. D., Galand, M., Geiger, B., Goetz, C., Grieger, B., Guettler, C., Henri, P., Hofstadter, M., Horanyi, M., Jehin, E., Krueger, H., Lee, S., Mannel, T., Morales, E., Mousis, O., Mueller, M., Opitom, C., Rotundi, A., Schmied, R., Schmidt, F., Sierks, H., Snodgrass, C., Soja, R. H., Sommer, M., Srama, R., Tzou, C. -Y, Vincent, J. -B, Yanamandra-Fisher, P., A'Hearn, M. F., Eriksson, Anders, Barbieri, C., Barucci, M. A., Bertaux, J. -L, Bertini, I., Burch, J., Colangeli, L., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Deller, J., Feaga, L. M., Ferrari, M., Fornasier, S., Fulle, M., Gicquel, A., Gillon, M., Green, S. F., Groussin, O., Gutierrez, P. J., Hofmann, M., Hviid, S. F., Ip, W. -H, Ivanovski, S., Jorda, L., Keller, H. U., Knight, M. M., Knollenberg, J., Koschny, D., Kramm, J. -R, Kuehrt, E., Kuppers, M., Lamy, P. L., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Manfroid, J., Epifani, E. Mazzotta, Marzari, F., Naletto, G., Oklay, N., Palumbo, P., Parker, J. Wm., Rickman, Hans, Rodrigo, R., Rodriguez, J., Schindhelm, E., Shi, X., Sordini, R., Steffl, A. J., Stern, S. A., Thomas, N., Tubiana, C., Weaver, H. A., Weissman, P., and Zakharov, V. V.

Abstract

On 2016 Feb 19, nine Rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus of comet 67P/Churyumov-Gerasimenko. Among these instruments were cameras and spectrometers ranging from UV over visible to microwave wavelengths, in situ gas, dust and plasma instruments, and one dust collector. At 09: 40 a dust cloud developed at the edge of an image in the shadowed region of the nucleus. Over the next two hours the instruments recorded a signature of the outburst that significantly exceeded the background. The enhancement ranged from 50 per cent of the neutral gas density at Rosetta to factors > 100 of the brightness of the coma near the nucleus. Dust related phenomena (dust counts or brightness due to illuminated dust) showed the strongest enhancements (factors > 10). However, even the electron density at Rosetta increased by a factor 3 and consequently the spacecraft potential changed from similar to-16 V to -20 V during the outburst. A clear sequence of events was observed at the distance of Rosetta ( 34 km from the nucleus): within 15 min the Star Tracker camera detected fast particles (similar to 25 m s(-1)) while 100 mu m radius particles were detected by the GIADA dust instrument similar to 1 h later at a speed of 6 m s(-1). The slowest were individual mm to cm sized grains observed by the OSIRIS cameras. Although the outburst originated just outside the FOV of the instruments, the source region and the magnitude of the outburst could be determined.

Published
2016
Full Text
View/download PDF

5. The 2016 Feb 19 outburst of comet 67P/CG : an ESA Rosetta multi-instrument study

Author

Grun, E., Agarwal, J., Altobelli, N., Altwegg, K., Bentley, M. S., Biver, N., Della Corte, V., Edberg, Niklas J. T., Feldman, P. D., Galand, M., Geiger, B., Goetz, C., Grieger, B., Guettler, C., Henri, P., Hofstadter, M., Horanyi, M., Jehin, E., Krueger, H., Lee, S., Mannel, T., Morales, E., Mousis, O., Mueller, M., Opitom, C., Rotundi, A., Schmied, R., Schmidt, F., Sierks, H., Snodgrass, C., Soja, R. H., Sommer, M., Srama, R., Tzou, C. -Y, Vincent, J. -B, Yanamandra-Fisher, P., A'Hearn, M. F., Eriksson, Anders, Barbieri, C., Barucci, M. A., Bertaux, J. -L, Bertini, I., Burch, J., Colangeli, L., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Deller, J., Feaga, L. M., Ferrari, M., Fornasier, S., Fulle, M., Gicquel, A., Gillon, M., Green, S. F., Groussin, O., Gutierrez, P. J., Hofmann, M., Hviid, S. F., Ip, W. -H, Ivanovski, S., Jorda, L., Keller, H. U., Knight, M. M., Knollenberg, J., Koschny, D., Kramm, J. -R, Kuehrt, E., Kuppers, M., Lamy, P. L., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Manfroid, J., Epifani, E. Mazzotta, Marzari, F., Naletto, G., Oklay, N., Palumbo, P., Parker, J. Wm., Rickman, Hans, Rodrigo, R., Rodriguez, J., Schindhelm, E., Shi, X., Sordini, R., Steffl, A. J., Stern, S. A., Thomas, N., Tubiana, C., Weaver, H. A., Weissman, P., Zakharov, V. V., Grun, E., Agarwal, J., Altobelli, N., Altwegg, K., Bentley, M. S., Biver, N., Della Corte, V., Edberg, Niklas J. T., Feldman, P. D., Galand, M., Geiger, B., Goetz, C., Grieger, B., Guettler, C., Henri, P., Hofstadter, M., Horanyi, M., Jehin, E., Krueger, H., Lee, S., Mannel, T., Morales, E., Mousis, O., Mueller, M., Opitom, C., Rotundi, A., Schmied, R., Schmidt, F., Sierks, H., Snodgrass, C., Soja, R. H., Sommer, M., Srama, R., Tzou, C. -Y, Vincent, J. -B, Yanamandra-Fisher, P., A'Hearn, M. F., Eriksson, Anders, Barbieri, C., Barucci, M. A., Bertaux, J. -L, Bertini, I., Burch, J., Colangeli, L., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Deller, J., Feaga, L. M., Ferrari, M., Fornasier, S., Fulle, M., Gicquel, A., Gillon, M., Green, S. F., Groussin, O., Gutierrez, P. J., Hofmann, M., Hviid, S. F., Ip, W. -H, Ivanovski, S., Jorda, L., Keller, H. U., Knight, M. M., Knollenberg, J., Koschny, D., Kramm, J. -R, Kuehrt, E., Kuppers, M., Lamy, P. L., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Manfroid, J., Epifani, E. Mazzotta, Marzari, F., Naletto, G., Oklay, N., Palumbo, P., Parker, J. Wm., Rickman, Hans, Rodrigo, R., Rodriguez, J., Schindhelm, E., Shi, X., Sordini, R., Steffl, A. J., Stern, S. A., Thomas, N., Tubiana, C., Weaver, H. A., Weissman, P., and Zakharov, V. V.

Abstract

On 2016 Feb 19, nine Rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus of comet 67P/Churyumov-Gerasimenko. Among these instruments were cameras and spectrometers ranging from UV over visible to microwave wavelengths, in situ gas, dust and plasma instruments, and one dust collector. At 09: 40 a dust cloud developed at the edge of an image in the shadowed region of the nucleus. Over the next two hours the instruments recorded a signature of the outburst that significantly exceeded the background. The enhancement ranged from 50 per cent of the neutral gas density at Rosetta to factors > 100 of the brightness of the coma near the nucleus. Dust related phenomena (dust counts or brightness due to illuminated dust) showed the strongest enhancements (factors > 10). However, even the electron density at Rosetta increased by a factor 3 and consequently the spacecraft potential changed from similar to-16 V to -20 V during the outburst. A clear sequence of events was observed at the distance of Rosetta ( 34 km from the nucleus): within 15 min the Star Tracker camera detected fast particles (similar to 25 m s(-1)) while 100 mu m radius particles were detected by the GIADA dust instrument similar to 1 h later at a speed of 6 m s(-1). The slowest were individual mm to cm sized grains observed by the OSIRIS cameras. Although the outburst originated just outside the FOV of the instruments, the source region and the magnitude of the outburst could be determined.

Published
2016
Full Text
View/download PDF

6. Ion chemistry in the coma of comet 67P near perihelion

Author

Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., Wurz, P., Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., and Wurz, P.

Abstract

The coma and the comet-solar wind interaction of comet 67P/Churyumov-Gerasimenko changed dramatically from the initial Rosetta spacecraft encounter in 2014 August through perihelion in 2015 August. Just before equinox (at 1.6 au from the Sun), the solar wind signal disappeared and two regions of different cometary ion characteristics were observed. These 'outer' and 'inner' regions have cometary ion characteristics similar to outside and inside the ion pileup region observed during the Giotto approach to comet 1P/Halley. Rosetta/Double-Focusing Mass Spectrometer ion mass spectrometer observations are used here to investigate the H3O+/H2O+ ratio in the outer and inner regions at 67P/Churyumov-Gerasimenko. The H3O+/H2O+ ratio and the H3O+ signal are observed to increase in the transition from the outer to the inner region and the H3O+ signal appears to be weakly correlated with cometary ion energy. These ion composition changes are similar to the ones observed during the 1P/Halley flyby. Modelling is used to determine the importance of neutral composition and transport of neutrals and ions away from the nucleus. This modelling demonstrates that changes in the H3O+/H2O+ ratio appear to be driven largely by transport properties and only weakly by neutral composition in the coma.

Published
2016
Full Text
View/download PDF

7. Ion chemistry in the coma of comet 67P near perihelion

Author

Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., Wurz, P., Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., and Wurz, P.

Abstract

The coma and the comet-solar wind interaction of comet 67P/Churyumov-Gerasimenko changed dramatically from the initial Rosetta spacecraft encounter in 2014 August through perihelion in 2015 August. Just before equinox (at 1.6 au from the Sun), the solar wind signal disappeared and two regions of different cometary ion characteristics were observed. These 'outer' and 'inner' regions have cometary ion characteristics similar to outside and inside the ion pileup region observed during the Giotto approach to comet 1P/Halley. Rosetta/Double-Focusing Mass Spectrometer ion mass spectrometer observations are used here to investigate the H3O+/H2O+ ratio in the outer and inner regions at 67P/Churyumov-Gerasimenko. The H3O+/H2O+ ratio and the H3O+ signal are observed to increase in the transition from the outer to the inner region and the H3O+ signal appears to be weakly correlated with cometary ion energy. These ion composition changes are similar to the ones observed during the 1P/Halley flyby. Modelling is used to determine the importance of neutral composition and transport of neutrals and ions away from the nucleus. This modelling demonstrates that changes in the H3O+/H2O+ ratio appear to be driven largely by transport properties and only weakly by neutral composition in the coma.

Published
2016
Full Text
View/download PDF

8. The 2016 Feb 19 outburst of comet 67P/CG : an ESA Rosetta multi-instrument study

Author

Grun, E., Agarwal, J., Altobelli, N., Altwegg, K., Bentley, M. S., Biver, N., Della Corte, V., Edberg, Niklas J. T., Feldman, P. D., Galand, M., Geiger, B., Goetz, C., Grieger, B., Guettler, C., Henri, P., Hofstadter, M., Horanyi, M., Jehin, E., Krueger, H., Lee, S., Mannel, T., Morales, E., Mousis, O., Mueller, M., Opitom, C., Rotundi, A., Schmied, R., Schmidt, F., Sierks, H., Snodgrass, C., Soja, R. H., Sommer, M., Srama, R., Tzou, C. -Y, Vincent, J. -B, Yanamandra-Fisher, P., A'Hearn, M. F., Eriksson, Anders, Barbieri, C., Barucci, M. A., Bertaux, J. -L, Bertini, I., Burch, J., Colangeli, L., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Deller, J., Feaga, L. M., Ferrari, M., Fornasier, S., Fulle, M., Gicquel, A., Gillon, M., Green, S. F., Groussin, O., Gutierrez, P. J., Hofmann, M., Hviid, S. F., Ip, W. -H, Ivanovski, S., Jorda, L., Keller, H. U., Knight, M. M., Knollenberg, J., Koschny, D., Kramm, J. -R, Kuehrt, E., Kuppers, M., Lamy, P. L., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Manfroid, J., Epifani, E. Mazzotta, Marzari, F., Naletto, G., Oklay, N., Palumbo, P., Parker, J. Wm., Rickman, Hans, Rodrigo, R., Rodriguez, J., Schindhelm, E., Shi, X., Sordini, R., Steffl, A. J., Stern, S. A., Thomas, N., Tubiana, C., Weaver, H. A., Weissman, P., Zakharov, V. V., Grun, E., Agarwal, J., Altobelli, N., Altwegg, K., Bentley, M. S., Biver, N., Della Corte, V., Edberg, Niklas J. T., Feldman, P. D., Galand, M., Geiger, B., Goetz, C., Grieger, B., Guettler, C., Henri, P., Hofstadter, M., Horanyi, M., Jehin, E., Krueger, H., Lee, S., Mannel, T., Morales, E., Mousis, O., Mueller, M., Opitom, C., Rotundi, A., Schmied, R., Schmidt, F., Sierks, H., Snodgrass, C., Soja, R. H., Sommer, M., Srama, R., Tzou, C. -Y, Vincent, J. -B, Yanamandra-Fisher, P., A'Hearn, M. F., Eriksson, Anders, Barbieri, C., Barucci, M. A., Bertaux, J. -L, Bertini, I., Burch, J., Colangeli, L., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Deller, J., Feaga, L. M., Ferrari, M., Fornasier, S., Fulle, M., Gicquel, A., Gillon, M., Green, S. F., Groussin, O., Gutierrez, P. J., Hofmann, M., Hviid, S. F., Ip, W. -H, Ivanovski, S., Jorda, L., Keller, H. U., Knight, M. M., Knollenberg, J., Koschny, D., Kramm, J. -R, Kuehrt, E., Kuppers, M., Lamy, P. L., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Manfroid, J., Epifani, E. Mazzotta, Marzari, F., Naletto, G., Oklay, N., Palumbo, P., Parker, J. Wm., Rickman, Hans, Rodrigo, R., Rodriguez, J., Schindhelm, E., Shi, X., Sordini, R., Steffl, A. J., Stern, S. A., Thomas, N., Tubiana, C., Weaver, H. A., Weissman, P., and Zakharov, V. V.

Abstract

On 2016 Feb 19, nine Rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus of comet 67P/Churyumov-Gerasimenko. Among these instruments were cameras and spectrometers ranging from UV over visible to microwave wavelengths, in situ gas, dust and plasma instruments, and one dust collector. At 09: 40 a dust cloud developed at the edge of an image in the shadowed region of the nucleus. Over the next two hours the instruments recorded a signature of the outburst that significantly exceeded the background. The enhancement ranged from 50 per cent of the neutral gas density at Rosetta to factors > 100 of the brightness of the coma near the nucleus. Dust related phenomena (dust counts or brightness due to illuminated dust) showed the strongest enhancements (factors > 10). However, even the electron density at Rosetta increased by a factor 3 and consequently the spacecraft potential changed from similar to-16 V to -20 V during the outburst. A clear sequence of events was observed at the distance of Rosetta ( 34 km from the nucleus): within 15 min the Star Tracker camera detected fast particles (similar to 25 m s(-1)) while 100 mu m radius particles were detected by the GIADA dust instrument similar to 1 h later at a speed of 6 m s(-1). The slowest were individual mm to cm sized grains observed by the OSIRIS cameras. Although the outburst originated just outside the FOV of the instruments, the source region and the magnitude of the outburst could be determined.

Published
2016
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9. Ion chemistry in the coma of comet 67P near perihelion

Author

Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., Wurz, P., Fuselier, S. A., Altwegg, K., Balsiger, H., Berthelier, J. J., Beth, A., Bieler, A., Briois, C., Broiles, T. W., Burch, J. L., Calmonte, U., Cessateur, G., Combi, M., De Keyser, J., Fiethe, B., Galand, M., Gasc, S., Gombosi, T. I., Gunell, H., Hansen, K. C., Hassig, M., Heritier, K. L., Korth, A., Le Roy, L., Luspay-Kuti, A., Mall, U., Mandt, K. E., Petrinec, S. M., Reme, H., Rinaldi, M., Rubin, M., Semon, T., Trattner, K. J., Tzou, C. -Y, Vigren, Erik, Waite, J. H., and Wurz, P.

Abstract

The coma and the comet-solar wind interaction of comet 67P/Churyumov-Gerasimenko changed dramatically from the initial Rosetta spacecraft encounter in 2014 August through perihelion in 2015 August. Just before equinox (at 1.6 au from the Sun), the solar wind signal disappeared and two regions of different cometary ion characteristics were observed. These 'outer' and 'inner' regions have cometary ion characteristics similar to outside and inside the ion pileup region observed during the Giotto approach to comet 1P/Halley. Rosetta/Double-Focusing Mass Spectrometer ion mass spectrometer observations are used here to investigate the H3O+/H2O+ ratio in the outer and inner regions at 67P/Churyumov-Gerasimenko. The H3O+/H2O+ ratio and the H3O+ signal are observed to increase in the transition from the outer to the inner region and the H3O+ signal appears to be weakly correlated with cometary ion energy. These ion composition changes are similar to the ones observed during the 1P/Halley flyby. Modelling is used to determine the importance of neutral composition and transport of neutrals and ions away from the nucleus. This modelling demonstrates that changes in the H3O+/H2O+ ratio appear to be driven largely by transport properties and only weakly by neutral composition in the coma.

Published
2016
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10. The 2016 Feb 19 outburst of comet 67P/CG : an ESA Rosetta multi-instrument study

Author

Grun, E., Agarwal, J., Altobelli, N., Altwegg, K., Bentley, M. S., Biver, N., Della Corte, V., Edberg, Niklas J. T., Feldman, P. D., Galand, M., Geiger, B., Goetz, C., Grieger, B., Guettler, C., Henri, P., Hofstadter, M., Horanyi, M., Jehin, E., Krueger, H., Lee, S., Mannel, T., Morales, E., Mousis, O., Mueller, M., Opitom, C., Rotundi, A., Schmied, R., Schmidt, F., Sierks, H., Snodgrass, C., Soja, R. H., Sommer, M., Srama, R., Tzou, C. -Y, Vincent, J. -B, Yanamandra-Fisher, P., A'Hearn, M. F., Eriksson, Anders, Barbieri, C., Barucci, M. A., Bertaux, J. -L, Bertini, I., Burch, J., Colangeli, L., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Deller, J., Feaga, L. M., Ferrari, M., Fornasier, S., Fulle, M., Gicquel, A., Gillon, M., Green, S. F., Groussin, O., Gutierrez, P. J., Hofmann, M., Hviid, S. F., Ip, W. -H, Ivanovski, S., Jorda, L., Keller, H. U., Knight, M. M., Knollenberg, J., Koschny, D., Kramm, J. -R, Kuehrt, E., Kuppers, M., Lamy, P. L., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Manfroid, J., Epifani, E. Mazzotta, Marzari, F., Naletto, G., Oklay, N., Palumbo, P., Parker, J. Wm., Rickman, Hans, Rodrigo, R., Rodriguez, J., Schindhelm, E., Shi, X., Sordini, R., Steffl, A. J., Stern, S. A., Thomas, N., Tubiana, C., Weaver, H. A., Weissman, P., Zakharov, V. V., Grun, E., Agarwal, J., Altobelli, N., Altwegg, K., Bentley, M. S., Biver, N., Della Corte, V., Edberg, Niklas J. T., Feldman, P. D., Galand, M., Geiger, B., Goetz, C., Grieger, B., Guettler, C., Henri, P., Hofstadter, M., Horanyi, M., Jehin, E., Krueger, H., Lee, S., Mannel, T., Morales, E., Mousis, O., Mueller, M., Opitom, C., Rotundi, A., Schmied, R., Schmidt, F., Sierks, H., Snodgrass, C., Soja, R. H., Sommer, M., Srama, R., Tzou, C. -Y, Vincent, J. -B, Yanamandra-Fisher, P., A'Hearn, M. F., Eriksson, Anders, Barbieri, C., Barucci, M. A., Bertaux, J. -L, Bertini, I., Burch, J., Colangeli, L., Cremonese, G., Da Deppo, V., Davidsson, Björn, Debei, S., De Cecco, M., Deller, J., Feaga, L. M., Ferrari, M., Fornasier, S., Fulle, M., Gicquel, A., Gillon, M., Green, S. F., Groussin, O., Gutierrez, P. J., Hofmann, M., Hviid, S. F., Ip, W. -H, Ivanovski, S., Jorda, L., Keller, H. U., Knight, M. M., Knollenberg, J., Koschny, D., Kramm, J. -R, Kuehrt, E., Kuppers, M., Lamy, P. L., Lara, L. M., Lazzarin, M., Lopez-Moreno, J. J., Manfroid, J., Epifani, E. Mazzotta, Marzari, F., Naletto, G., Oklay, N., Palumbo, P., Parker, J. Wm., Rickman, Hans, Rodrigo, R., Rodriguez, J., Schindhelm, E., Shi, X., Sordini, R., Steffl, A. J., Stern, S. A., Thomas, N., Tubiana, C., Weaver, H. A., Weissman, P., and Zakharov, V. V.

Abstract

On 2016 Feb 19, nine Rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus of comet 67P/Churyumov-Gerasimenko. Among these instruments were cameras and spectrometers ranging from UV over visible to microwave wavelengths, in situ gas, dust and plasma instruments, and one dust collector. At 09: 40 a dust cloud developed at the edge of an image in the shadowed region of the nucleus. Over the next two hours the instruments recorded a signature of the outburst that significantly exceeded the background. The enhancement ranged from 50 per cent of the neutral gas density at Rosetta to factors > 100 of the brightness of the coma near the nucleus. Dust related phenomena (dust counts or brightness due to illuminated dust) showed the strongest enhancements (factors > 10). However, even the electron density at Rosetta increased by a factor 3 and consequently the spacecraft potential changed from similar to-16 V to -20 V during the outburst. A clear sequence of events was observed at the distance of Rosetta ( 34 km from the nucleus): within 15 min the Star Tracker camera detected fast particles (similar to 25 m s(-1)) while 100 mu m radius particles were detected by the GIADA dust instrument similar to 1 h later at a speed of 6 m s(-1). The slowest were individual mm to cm sized grains observed by the OSIRIS cameras. Although the outburst originated just outside the FOV of the instruments, the source region and the magnitude of the outburst could be determined.

Published
2016
Full Text
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