Sub-Micrometer Particles Remote Detection in Enceladus’ Plume Based on Cassini’s UV Spectrograph Data

eng Artykuł w języku angielskim DOI: 10.14313/PAR_251/107

wyślij Jan Kotlarz *, Katarzyna Kubiak *, Natalia Zalewska ** * Research Network Łukasiewicz – Institute of Aviation, Al. Krakowska 110/114, 02-256 Warsaw, Poland ** Space Research Center, Polish Academy of Sciences, Bartycka 18A, 00-716 Warsaw, Poland

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Enceladus is the Saturnian satellite is known to have water vapor erupting from its south pole region called „Tiger Stripes”. Data collected by Cassini Ultraviolet Imaging Spectrograph during Enceladus transiting Saturn allow us to estimate water plume absorption from 1115.35–1912.50 Å and compare it to the Mie solutions of Maxwell equations for particles with a diameter in the range from 10 nm up to 2 µm. The best fit performed using Gradient Descent method indicates a presence of sub-micrometer particles of diameters: 120–180 nm and 240–320 nm consistent with Thermofilum sp., Thermoproteus sp., and Pyrobaculum sp. cell sizes present in hydrothermal vents on Earth.


astrobiology, Enceladus, Mie scattering, remote sensing, space mission

Detekcja cząstek submikrometrowych w pióropuszu Enceladusa na podstawie danych ze spektrografu UV sondy Cassini


Enceladus, księżyc Saturna, jest charakterystyczny ze względu na erupcje pary wodnej z regionu jego bieguna południowego, tzw. „Tiger Stripes”. Dane zebrane przez instrument sondy Cassini: Ultraviolet Imaging Spectrograph podczas tranzytu Enceladusa przed tarczą Saturna pozwalają oszacować absorpcję światła przez pióropusze wodne w zakresie 1115,35–1912,50 Å i porównać ją z rozwiązaniami Mie równań Maxwella dla cząsteczek o średnicach w zakresie od 10 nm do 2 µm. Najlepsze dopasowanie wykonane metodą Gradient Descent wskazuje na obecność cząstek sub-mikrometrowych o średnicach: 120–180 nm i 240–320 nm zgodnych z rozmiarami komórek Thermofilum sp., Thermoproteus sp. i Pyrobaculum sp. obecnych w kominach hydrotermalnych na Ziemi.

Słowa kluczowe

astrobiologia, Enceladus, misja kosmiczna, rozpraszanie Mie, teledetekcja


  1. Bedrossian M., Lindensmith C., Nadeau J.L., Digital Holographic Microscopy, a Method for Detection of Microorganisms in Plume Samples from Enceladus and Other Icy Worlds. “Astrobiology”, Vol. 17, No. 9, 2017, 913–925, DOI: 10.1089/ast.2016.1616.
  2. Bohren C.F., Huffman D.R., Absorption and scattering of light by small particles. John Wiley & Sons, 2008.
  3. Gao P., Kopparla P., Zhang X., Ingersoll A.P., Aggregate particles in the plumes of Enceladus. “Icarus”, Vol. 264, 2016, 227–238, DOI: 10.1016/j.icarus.2015.09.030.
  4. Hansen C., Esposito L., Colwell J., Hendrix A., Portyankina G., Stewart A., West R. The composition and structure of Enceladus’ plume from the complete set of Cassini UVIS occultation observations, “Icarus”, Vol. 344, 2020, DOI: 10.1016/j.icarus.2019.113461.
  5. Hansen C., Esposito L., Hendrix A., Ultraviolet observation of Enceladus’ plume in transit across Saturn, compared to Europa. “Icarus”, Vol. 330, 2019, 256–260, DOI: 10.1016/j.icarus.2019.04.031.
  6. Hansen C.J., Esposito L., Stewart A., Colwell J., Hendrix A., Pryor W., Shemansky D., West R., Enceladus’ Water Vapor Plume. “Science”, Vol. 311, No. 5766, 2006, 1422–1425, DOI: 10.1126/science.1121254.
  7. Hedman M., Nicholson P., Showalter M., Brown R., Buratti B., Clark R., Spectral observations of the Enceladus plume with Cassini-VIMS. “The Astrophysical Journal”, Vol. 693, No. 2, 2009, DOI: 10.1088/0004-637X/693/2/1749.
  8. Hill T.W., Thomsen M., Tokar R., Coates A., Lewis G., Young D., Crary F., Baragiola R., Johnson R., Dong Y., Wilson R.J., Jones G.H., Wahlund J.-E., Mitchell D.G., Horányi M., Charged nanograins in the Enceladus plume. “Journal of Geophysical Research: Space Physics”, Vol. 117, No. A5, 2012, DOI: 10.1029/2011JA017218.
  9. Kubiak M.A. Gwiazdy i materia międzygwiazdowa. Wydawnictwo Naukowe PWN, 1994.
  10. Parashar S., Kral T., Possibility of methanogens on Enceladus. [In:] Astrobiology Science Conference 2010: Evolution and Life: Surviving Catastrophes and Extremes on Earth and Beyond, Vol. 1538, 2010.
  11. Porco C.C., Dones L., Mitchell C., Could it be snowing microbes on Enceladus? assessing conditions in its plume and implications for future missions. “Astrobiology”, 17(9): (2017), 876–901.
  12. Portyankina G., Esposito L.W., Aye K.-M., Hansen C.J., Modeling of the Enceladus water vapor jets for interpreting UVIS star and solar occultation observations. [In:] American Astronomical Society/Division for Planetary Sciences Meeting Abstracts# 47, 2015, 410.05.
  13. Portyankina G., Esposito L.W., Aye K.-M., Hansen C.J., Ali A., Modeling the complete set of Cassini’s UVIS occultation observations of Enceladus’ plume. “Icarus”, Vol. 383, 2022, DOI: 10.1016/j.icarus.2022.114918.
  14. Postberg F., Schmidt J., Hillier J., Kempf S., Srama R., A salt-water reservoir as the source of a compositionally stratified plume on Enceladus. “Nature”, Vol. 474, 2011, 620–622.
  15. Scipioni F., Schenk P., Tosi F., D’Aversa E., Clark R., Combe J.P., Dalle Ore C., Deciphering sub-micron ice particles on Enceladus surface. “Icarus”, Vol. 290, 2017, 183–200, DOI: 10.1016/j.icarus.2017.02.012.
  16. Spencer J., Pearl J., Segura M., Flasar F., Mamoutkine A., Romani P., Buratti B., Hendrix A., Spilker L., Lopes R., Cassini encounters Enceladus: Background and the discovery of a south polar hot spot. “Science”, Vol. 311, No. 5766, 2006, 1401–1405, DOI: 10.1126/science.1121661.
  17. Sumlin B.J., Heinson W.R., Chakrabarty R.K., Retrieving the aerosol complex refractive index using PyMieScatt: A Mie computational package with visualization capabilities. Journal of Quantitative Spectroscopy and Radiative Transfer, Vol. 205, 2018, 127–134, DOI: 10.1016/j.jqsrt.2017.10.012.
  18. Taubner R.-S., Pappenreiter P., Zwicker J., Smrzka D., Pruckner C., Kolar P., Bernacchi S., Seifert A.H., Krajete A., Bach W., Peckmann J., Paulik Ch., Firneis M.G., Schleper Ch., Rittmann S.K.-M.R., Biological methane production under putative Enceladus-like conditions. “Nature communications”, Vol. 9, 2018, DOI: 10.1038/s41467-018-02876-y.
  19. Wang N., Du B., Zhang L., Zhang L., An abundance characteristic-based independent component analysis for hyperspectral unmixing. “IEEE Transactions on Geoscience and Remote Sensing”, Vol. 53, No. 1, 2015, 416–428, DOI: 10.1109/TGRS.2014.2322862.
  20. Wang Z.B., Luk’Yanchuk B.S., Hong M.H., Lin Y., Chong T.C., Energy flow around a small particle investigated by classical Mie theory. “Physical Review B”, Vol. 70, No. 3, 2004, DOI: 10.1103/PhysRevB.70.035418.
  21. Wolf S., Voshchinnikov N., Mie scattering by ensembles of particles with very large size parameters. “Computer Physics Communications”, Vol. 162, No. 2, 2004, 113–123, DOI: 10.1016/j.cpc.2004.06.070.