Evolution of the ion environment of comet 67P/Churyumov-Gerasimenko: Observations between 3.6 and 2.0 AU

H. Nilsson, G. Stenberg Wieser, E. Behar, C. Simon Wedlund, E. Kallio, H. Gunell, N. J T Edberg, A. I. Eriksson, M. Yamauchi, C. Koenders, M. Wieser, R. Lundin, S. Barabash, K. Mandt, J. L. Burch, R. Goldstein, P. Mokashi, C. Carr, E. Cupido, P. T. FoxK. Szegö, Z. Nemeth, A. Fedorov, J. A. Sauvaud, H. Koskinen, I. Richter, J. P. Lebreton, P. Henri, M. Volwerk, C. Vallat, B. Geiger

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

The Rosetta spacecraft is escorting comet 67P/Churyumov-Gerasimenko from a heliocentric distance of >3.6 AU, where the comet activity was low, until perihelion at 1.24 AU. Initially, the solar wind permeates the thin comet atmosphere formed from sublimation. Using the Rosetta Plasma Consortium Ion Composition Analyzer (RPC-ICA), we study the gradual evolution of the comet ion environment, from the first detectable traces of water ions to the stage where cometary water ions accelerated to about 1 keV energy are abundant. We compare ion fluxes of solar wind and cometary origin. Methods. RPC-ICA is an ion mass spectrometer measuring ions of solar wind and cometary origins in the 10 eV-40 keV energy range. Results. We show how the flux of accelerated water ions with energies above 120 eV increases between 3.6 and 2.0 AU. The 24 h average increases by 4 orders of magnitude, mainly because high-flux periods become more common. The water ion energy spectra also become broader with time. This may indicate a larger and more uniform source region. At 2.0 AU the accelerated water ion flux is frequently of the same order as the solar wind proton flux. Water ions of 120 eV-few keV energy may thus constitute a significant part of the ions sputtering the nucleus surface. The ion density and mass in the comet vicinity is dominated by ions of cometary origin. The solar wind is deflected and the energy spectra broadened compared to an undisturbed solar wind. Conclusions. The flux of accelerated water ions moving from the upstream direction back toward the nucleus is a strongly nonlinear function of the heliocentric distance.

Original languageEnglish
Article numberA20
JournalAstronomy and Astrophysics
Volume583
DOIs
Publication statusPublished - Nov 1 2015

Fingerprint

comets
comet
ion
ions
solar wind
water
energy
mass spectrometers
analyzers
energy spectra
nuclei
plasma
sublimation
upstream
spacecraft
sputtering

Keywords

  • Acceleration of particles
  • Comets: general
  • Comets: individual: 67P/Churyumov-Gerasimenko
  • Plasmas

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Nilsson, H., Stenberg Wieser, G., Behar, E., Simon Wedlund, C., Kallio, E., Gunell, H., ... Geiger, B. (2015). Evolution of the ion environment of comet 67P/Churyumov-Gerasimenko: Observations between 3.6 and 2.0 AU. Astronomy and Astrophysics, 583, [A20]. https://doi.org/10.1051/0004-6361/201526142

Evolution of the ion environment of comet 67P/Churyumov-Gerasimenko : Observations between 3.6 and 2.0 AU. / Nilsson, H.; Stenberg Wieser, G.; Behar, E.; Simon Wedlund, C.; Kallio, E.; Gunell, H.; Edberg, N. J T; Eriksson, A. I.; Yamauchi, M.; Koenders, C.; Wieser, M.; Lundin, R.; Barabash, S.; Mandt, K.; Burch, J. L.; Goldstein, R.; Mokashi, P.; Carr, C.; Cupido, E.; Fox, P. T.; Szegö, K.; Nemeth, Z.; Fedorov, A.; Sauvaud, J. A.; Koskinen, H.; Richter, I.; Lebreton, J. P.; Henri, P.; Volwerk, M.; Vallat, C.; Geiger, B.

In: Astronomy and Astrophysics, Vol. 583, A20, 01.11.2015.

Research output: Contribution to journalArticle

Nilsson, H, Stenberg Wieser, G, Behar, E, Simon Wedlund, C, Kallio, E, Gunell, H, Edberg, NJT, Eriksson, AI, Yamauchi, M, Koenders, C, Wieser, M, Lundin, R, Barabash, S, Mandt, K, Burch, JL, Goldstein, R, Mokashi, P, Carr, C, Cupido, E, Fox, PT, Szegö, K, Nemeth, Z, Fedorov, A, Sauvaud, JA, Koskinen, H, Richter, I, Lebreton, JP, Henri, P, Volwerk, M, Vallat, C & Geiger, B 2015, 'Evolution of the ion environment of comet 67P/Churyumov-Gerasimenko: Observations between 3.6 and 2.0 AU', Astronomy and Astrophysics, vol. 583, A20. https://doi.org/10.1051/0004-6361/201526142
Nilsson, H. ; Stenberg Wieser, G. ; Behar, E. ; Simon Wedlund, C. ; Kallio, E. ; Gunell, H. ; Edberg, N. J T ; Eriksson, A. I. ; Yamauchi, M. ; Koenders, C. ; Wieser, M. ; Lundin, R. ; Barabash, S. ; Mandt, K. ; Burch, J. L. ; Goldstein, R. ; Mokashi, P. ; Carr, C. ; Cupido, E. ; Fox, P. T. ; Szegö, K. ; Nemeth, Z. ; Fedorov, A. ; Sauvaud, J. A. ; Koskinen, H. ; Richter, I. ; Lebreton, J. P. ; Henri, P. ; Volwerk, M. ; Vallat, C. ; Geiger, B. / Evolution of the ion environment of comet 67P/Churyumov-Gerasimenko : Observations between 3.6 and 2.0 AU. In: Astronomy and Astrophysics. 2015 ; Vol. 583.
@article{2d370ebec7c8487399146698caf2af59,
title = "Evolution of the ion environment of comet 67P/Churyumov-Gerasimenko: Observations between 3.6 and 2.0 AU",
abstract = "The Rosetta spacecraft is escorting comet 67P/Churyumov-Gerasimenko from a heliocentric distance of >3.6 AU, where the comet activity was low, until perihelion at 1.24 AU. Initially, the solar wind permeates the thin comet atmosphere formed from sublimation. Using the Rosetta Plasma Consortium Ion Composition Analyzer (RPC-ICA), we study the gradual evolution of the comet ion environment, from the first detectable traces of water ions to the stage where cometary water ions accelerated to about 1 keV energy are abundant. We compare ion fluxes of solar wind and cometary origin. Methods. RPC-ICA is an ion mass spectrometer measuring ions of solar wind and cometary origins in the 10 eV-40 keV energy range. Results. We show how the flux of accelerated water ions with energies above 120 eV increases between 3.6 and 2.0 AU. The 24 h average increases by 4 orders of magnitude, mainly because high-flux periods become more common. The water ion energy spectra also become broader with time. This may indicate a larger and more uniform source region. At 2.0 AU the accelerated water ion flux is frequently of the same order as the solar wind proton flux. Water ions of 120 eV-few keV energy may thus constitute a significant part of the ions sputtering the nucleus surface. The ion density and mass in the comet vicinity is dominated by ions of cometary origin. The solar wind is deflected and the energy spectra broadened compared to an undisturbed solar wind. Conclusions. The flux of accelerated water ions moving from the upstream direction back toward the nucleus is a strongly nonlinear function of the heliocentric distance.",
keywords = "Acceleration of particles, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Plasmas",
author = "H. Nilsson and {Stenberg Wieser}, G. and E. Behar and {Simon Wedlund}, C. and E. Kallio and H. Gunell and Edberg, {N. J T} and Eriksson, {A. I.} and M. Yamauchi and C. Koenders and M. Wieser and R. Lundin and S. Barabash and K. Mandt and Burch, {J. L.} and R. Goldstein and P. Mokashi and C. Carr and E. Cupido and Fox, {P. T.} and K. Szeg{\"o} and Z. Nemeth and A. Fedorov and Sauvaud, {J. A.} and H. Koskinen and I. Richter and Lebreton, {J. P.} and P. Henri and M. Volwerk and C. Vallat and B. Geiger",
year = "2015",
month = "11",
day = "1",
doi = "10.1051/0004-6361/201526142",
language = "English",
volume = "583",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",

}

TY - JOUR

T1 - Evolution of the ion environment of comet 67P/Churyumov-Gerasimenko

T2 - Observations between 3.6 and 2.0 AU

AU - Nilsson, H.

AU - Stenberg Wieser, G.

AU - Behar, E.

AU - Simon Wedlund, C.

AU - Kallio, E.

AU - Gunell, H.

AU - Edberg, N. J T

AU - Eriksson, A. I.

AU - Yamauchi, M.

AU - Koenders, C.

AU - Wieser, M.

AU - Lundin, R.

AU - Barabash, S.

AU - Mandt, K.

AU - Burch, J. L.

AU - Goldstein, R.

AU - Mokashi, P.

AU - Carr, C.

AU - Cupido, E.

AU - Fox, P. T.

AU - Szegö, K.

AU - Nemeth, Z.

AU - Fedorov, A.

AU - Sauvaud, J. A.

AU - Koskinen, H.

AU - Richter, I.

AU - Lebreton, J. P.

AU - Henri, P.

AU - Volwerk, M.

AU - Vallat, C.

AU - Geiger, B.

PY - 2015/11/1

Y1 - 2015/11/1

N2 - The Rosetta spacecraft is escorting comet 67P/Churyumov-Gerasimenko from a heliocentric distance of >3.6 AU, where the comet activity was low, until perihelion at 1.24 AU. Initially, the solar wind permeates the thin comet atmosphere formed from sublimation. Using the Rosetta Plasma Consortium Ion Composition Analyzer (RPC-ICA), we study the gradual evolution of the comet ion environment, from the first detectable traces of water ions to the stage where cometary water ions accelerated to about 1 keV energy are abundant. We compare ion fluxes of solar wind and cometary origin. Methods. RPC-ICA is an ion mass spectrometer measuring ions of solar wind and cometary origins in the 10 eV-40 keV energy range. Results. We show how the flux of accelerated water ions with energies above 120 eV increases between 3.6 and 2.0 AU. The 24 h average increases by 4 orders of magnitude, mainly because high-flux periods become more common. The water ion energy spectra also become broader with time. This may indicate a larger and more uniform source region. At 2.0 AU the accelerated water ion flux is frequently of the same order as the solar wind proton flux. Water ions of 120 eV-few keV energy may thus constitute a significant part of the ions sputtering the nucleus surface. The ion density and mass in the comet vicinity is dominated by ions of cometary origin. The solar wind is deflected and the energy spectra broadened compared to an undisturbed solar wind. Conclusions. The flux of accelerated water ions moving from the upstream direction back toward the nucleus is a strongly nonlinear function of the heliocentric distance.

AB - The Rosetta spacecraft is escorting comet 67P/Churyumov-Gerasimenko from a heliocentric distance of >3.6 AU, where the comet activity was low, until perihelion at 1.24 AU. Initially, the solar wind permeates the thin comet atmosphere formed from sublimation. Using the Rosetta Plasma Consortium Ion Composition Analyzer (RPC-ICA), we study the gradual evolution of the comet ion environment, from the first detectable traces of water ions to the stage where cometary water ions accelerated to about 1 keV energy are abundant. We compare ion fluxes of solar wind and cometary origin. Methods. RPC-ICA is an ion mass spectrometer measuring ions of solar wind and cometary origins in the 10 eV-40 keV energy range. Results. We show how the flux of accelerated water ions with energies above 120 eV increases between 3.6 and 2.0 AU. The 24 h average increases by 4 orders of magnitude, mainly because high-flux periods become more common. The water ion energy spectra also become broader with time. This may indicate a larger and more uniform source region. At 2.0 AU the accelerated water ion flux is frequently of the same order as the solar wind proton flux. Water ions of 120 eV-few keV energy may thus constitute a significant part of the ions sputtering the nucleus surface. The ion density and mass in the comet vicinity is dominated by ions of cometary origin. The solar wind is deflected and the energy spectra broadened compared to an undisturbed solar wind. Conclusions. The flux of accelerated water ions moving from the upstream direction back toward the nucleus is a strongly nonlinear function of the heliocentric distance.

KW - Acceleration of particles

KW - Comets: general

KW - Comets: individual: 67P/Churyumov-Gerasimenko

KW - Plasmas

UR - http://www.scopus.com/inward/record.url?scp=84934446720&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84934446720&partnerID=8YFLogxK

U2 - 10.1051/0004-6361/201526142

DO - 10.1051/0004-6361/201526142

M3 - Article

AN - SCOPUS:84934446720

VL - 583

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

M1 - A20

ER -