[en] In comets, iron and nickel are found in refractory dust particles or in metallic and sulfide grains. So far, no iron- or nickel-bearing molecules have been observed in the gaseous coma of comets. Iron and a few other heavy atoms, such as copper and cobalt, have been observed only in two exceptional objects: the Great Comet of 1882 and, almost a century later, C/1965 S1 (Ikeya-Seki). These sungrazing comets approached the Sun so closely that refractory materials sublimated, and their relative abundance of nickel to iron was similar to that of the Sun and meteorites. More recently, the presence of iron vapour was inferred from the properties of a faint tail in comet C/2006 P1 (McNaught) at perihelion, but neither iron nor nickel was reported in the gaseous coma of comet 67P/Churyumov-Gerasimenko by the in situ Rosetta mission. Here we report that neutral Fe I and Ni I emission lines are ubiquitous in cometary atmospheres, even far from the Sun, as revealed by high-resolution ultraviolet-optical spectra of a large sample of comets of various compositions and dynamical origins. The abundances of both species appear to be of the same order of magnitude, contrasting the typical Solar System abundance ratio.
Disciplines :
Aérospatiale, astronomie & astrophysique
Auteur, co-auteur :
Manfroid, Jean ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
Hutsemekers, Damien ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS)
Jehin, Emmanuel ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa)
Langue du document :
Anglais
Titre :
Iron and nickel atoms in cometary atmospheres even far from the Sun
Zolensky, M. E. et al. Mineralogy and petrology of comet 81P/Wild 2 nucleus samples. Science 314, 1735–1739 (2006).
Bockelée-Morvan, D. & Biver, N. The composition of cometary ices. Philos. Trans. R. Soc. Lond. A 375, 20160252 (2017).
Copeland, R. & Lohse, J. G. in Copernicus: an International Journal of Astronomy Vol. 2, 225–244 (1882).
Arpigny, C. in Liege International Astrophysical Colloquia Vol. 22 (eds Boury, A. et al.) 189–197 (1979).
Combi, M. R., DiSanti, M. A. & Fink, U. The spatial distribution of gaseous atomic sodium in the comae of comets: evidence for direct nucleus and extended plasma sources. Icarus 130, 336–354 (1997).
Dufay, J., Swings, P. & Fehrenbach, Ch. Spectrographic observations of comet Ikeya-Seki (1965f). Astrophys. J. 142, 1698 (1965).
Preston, G. W. The spectrum of Ikeya-Seki (1965f). Astrophys. J. 147, 718–742 (1967).
Slaughter, C. D. The emission spectrum of comet Ikeya-Seki 1965-f at perihelion passage. Astron. J. 74, 929 (1969).
Thackeray, A. D., Feast, M. W. & Warner, B. Daytime spectra of comet Ikeya-Seki near perihelion. Astrophys. J. 143, 276 (1966).
Fulle, M. et al. Discovery of the atomic iron tail of comet McNaught using the heliospheric imager on STEREO. Astrophys. J. Lett. 661, L93–L96 (2007).
Altwegg, K. & ROSINA Team. Chemical highlights from the Rosetta mission. In Proceedings of the International Astronomical Union Vol. 13, 153–162 (IAU, 2017).
Arpigny, C. et al. Anomalous nitrogen isotope ratio in comets. Science 301, 1522–1524 (2003).
Guzik, P. & Drahus, M. Gaseous atomic nickel in the coma of interstellar comet 2I/Borisov. Nature https://doi.org/10.1038/s41586-021-03485-4 (2021).
Arpigny, C. On the nature of comets. In Proceedings of the Robert A. Welch Foundation Conferences on Chemical Research XXI, Cosmochemistry (ed. Mulligan, W. O.) 9 (1978).
Cochran, A. L. & Schleicher, D. G. Observational constraints on the lifetime of cometary H2O. Icarus 105, 235–253 (1993).
Biver, N. et al. Long-term monitoring of the outgassing and composition of comet 67P/Churyumov–Gerasimenko with the Rosetta/MIRO instrument. Astron. Astrophys. 630, A19 (2019).
Womack, M., Sarid, G. & Wierzchos, K. CO in distantly active comets. Publ. Astron. Soc. Pacif. 129, 031001 (2017).
Lodders, K. Solar elemental abundances. In Oxford Research Encyclopedia of Planetary Science https://doi.org/10.1093/acrefore/9780190647926.013.145 (2020).
Larimer, J. W. & Anders, E. Chemical fractionations in meteorites – III. Major element fractionations in chondrites. Geochim. Cosmochim. Acta 34, 367–387 (1970).
Grossman, L. & Larimer, J. W. Early chemical history of the solar system. Rev. Geophys. Space Phys. 12, 71–101 (1974).
Lewis, J. S. Physics and Chemistry of the Solar System 2nd edn (Academic Press, 2004).
Berger, E. L., Zega, T. J., Keller, L. P. & Lauretta, D. S. Evidence for aqueous activity on comet 81P/Wild 2 from sulfide mineral assemblages in Stardust samples and CI chondrites. Geochim. Cosmochim. Acta 75, 3501–3513 (2011).
Bradley, J. P. Chemically anomalous, preaccretionally irradiated grains in interplanetary dust from comets. Science 265, 925–929 (1994).
Ishii, H. A. et al. Comparison of comet 81P/Wild 2 dust with interplanetary dust from comets. Science 319, 447 (2008).
Bockelée-Morvan, D. et al. Comet 67P outbursts and quiescent coma at 1.3 au from the Sun: dust properties from Rosetta/VIRTIS-H observations. Mon. Not. R. Astron. Soc. 469, S443–S458 (2017).
Hensley, B. S. & Draine, B. T. Thermodynamics and charging of interstellar iron nanoparticles. Astrophys. J. 834, 134 (2017).
Ip, W.-H. & Jorda, L. Can the sodium tail of Comet Hale–Bopp have a dust-impact origin? Astrophys. J. 496, L47–L49 (1998).
Wurz, P. et al. Solar wind sputtering of dust on the surface of 67P/Churyumov–Gerasimenko. Astron. Astrophys. 583, A22 (2015).
Bloch, M. R. & Wirth, H. L. Abiotic organic synthesis in space. Naturwissenschaften 67, 562–564 (1980).
Klotz, A. et al. Possible contribution of organometallic species in the solar system ices. Reactivity and spectroscopy. Planet. Space Sci. 44, 957–965 (1996).
Huebner, W. F. Dust from cometary nuclei. Astron. Astrophys. 5, 286–297 (1970).
Tarakeshwar, P., Buseck, P. R. & Timmes, F. X. On the structure, magnetic properties, and infrared spectra of iron pseudocarbynes in the interstellar medium. Astrophys. J. 879, 2 (2019).
Smith, K. E., House, C. H., Arevalo, R. D., Dworkin, J. P. & Callahan, M. P. Organometallic compounds as carriers of extraterrestrial cyanide in primitive meteorites. Nat. Commun. 10, 2777 (2019).
Prialnik, D., Benkhoff, J. & Podolak, M. in Comets II (eds Festou et al.) 359–387 (Univ. of Arizona Press, 2004).
Levison, H. F. Comet taxonomy. In Completing the Inventory of the Solar System Vol. 107 (eds. Rettig, T. W. & Hahn, J. M.) 173–191 (ASP, 1996).
A’Hearn, M. F., Schleicher, D. G., Millis, R. L., Feldman, P. D. & Thompson, D. T. Comet Bowell 1980b. Astron. J. 89, 579–591 (1984).
Schleicher, D. G. The fluorescence efficiencies of the CN violet bands in comets. Astron. J. 140, 973–984 (2010).
Schleicher, D. G. & A’Hearn, M. F. The fluorescence of cometary OH. Astrophys. J. 331, 1058 (1988).
Bhardwaj, A. & Raghuram, S. A coupled chemistry-emission model for atomic oxygen green and red-doublet emissions in the comet C/1996 B2 Hyakutake. Astrophys. J. 748, 13 (2012).
Raghuram, S. et al. A physico-chemical model to study the ion density distribution in the inner coma of comet C/2016 R2(Pan-STARRS). Mon. Not. R. Astron. Soc. 501, 4035–4052 (2021).
Weaver, H., Feldman, P., A’Hearn, M., Dello Russo, N. & Stern, A. Comet 103P/Hartley. IAU Circ. 9183, 1 (2010).
Roth, N. X. et al. Probing the evolutionary history of comets: an investigation of the hypervolatiles CO, CH4, and C2H6 in the Jupiter-family Comet 21P/Giacobini–Zinner. Astron. J. 159, 42 (2020).
DiSanti, M. A. et al. Depleted carbon monoxide in fragment C of the Jupiter-family comet 73P/Schwassmann–Wachmann 3. Astrophys. J. Lett. 661, L101–L104 (2007).
Böhnhardt, H. et al. The unusual volatile composition of the Halley-type comet 8P/Tuttle: addressing the existence of an inner Oort cloud. Astrophys. J. Lett. 683, L71 (2008).
Lupu, R. E., Feldman, P. D., Weaver, H. A. & Tozzi, G.-P. The fourth positive system of carbon monoxide in the Hubble Space Telescope spectra of comets. Astrophys. J. 670, 1473–1484 (2007).
DiSanti, M. A. et al. Detection of formaldehyde emission in comet C/2002 T7 (LINEAR) at infrared wavelengths: line-by-line validation of modeled fluorescent intensities. Astrophys. J. 650, 470–483 (2006).
Paganini, L. et al. Observations of comet C/2009 P1 (Garradd) at 2.4 and 2.0 AU before perihelion. In Asteroids, Comets, Meteors 2012 Vol. 1667, 6331 (Lunar Planetary Institute, 2012).
Paganini, L. et al. The unexpectedly bright comet C/2012 F6 (Lemmon) unveiled at near-infrared wavelengths. Astron. J. 147, 15 (2013).
Biver, N. et al. The extraordinary composition of the blue comet C/2016 R2 (PanSTARRS). Astron. Astrophys. 619, A127 (2018).
Wierzchos, K. & Womack, M. C/2016 R2 (PANSTARRS): a comet rich in CO and depleted in HCN. Astron. J. 156, 34 (2018).
Faggi, S., Mumma, M. J., Villanueva, G. L., Paganini, L. & Lippi, M. Quantifying the evolution of molecular production rates of comet 21P/Giacobini–Zinner with iSHELL/NASA-IRTF. Astron. J. 158, 254 (2019).
de Val-Borro, M. et al. A survey of volatile species in Oort cloud comets C/2001 Q4 (NEAT) and C/2002 T7 (LINEAR) at millimeter wavelengths. Astron. Astrophys. 559, A48 (2013).
Yamamoto, T., Nakagawa, N. & Fukui, Y. The chemical composition and thermal history of the ice of a cometary nucleus. Astron. Astrophys. 122, 171–176 (1983).
Yamamoto, T. Formation environment of cometary nuclei in the primordial solar nebula. Astron. Astrophys. 142, 31–36 (1985).
Gilbert, A. G. & Sulzmann, K. G. P. The vapor pressure of iron pentacarbonyl. J. Electrochem. Soc. 121, 832 (1974).
Stull, D. R. Vapor pressure of pure substances. Organic and inorganic compounds. Ind. Eng. Chem. 39, 517–540 (1947).
Delsemme, A. H. Chemical composition of cometary nuclei. In IAU Colloq. 61: Comet Discoveries, Statistics, and Observational Selection (ed. Wilkening, L. L.) 85–130 (IAU, 1982).
