Interplanetary dust particles sporadically enter planetary atmospheres at orbital velocities and ablate as collisions occur with ambient gases to produce a persistent layer of metallic atoms (for example, Fe, Mg, Na) in their upper atmospheres. Such layers are well studied at Earth, but have not been directly detected elsewhere in the Solar System. Here we report the detection of a meteoric layer consisting of Mg+ ions near an altitude of 90 km in the Martian atmosphere from ultraviolet remote sensing observations by NASA’s MAVEN spacecraft. We observe temporal variability in the Mg+ layer over the course of a Martian year, moving up and down in altitude seasonally and in response to dust storms, and displaying diurnal fluctuations in density. We also find that most meteor showers do not significantly perturb this layer, which constrains the fluence of eleven observed Martian meteor showers to less than our estimated global dust flux. The persistence and variability of the Mg+ layer are difficult to explain with existing models and reconcile with other transient layers of ions observed in the Martian ionosphere. We suggest that the transient layers are not sourced from the persistent Mg+ layer and thus not derived from meteoric material, but are ambient ions produced by some unknown mechanism.

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NASA supports the MAVEN mission through the Mars Scout programme. M.M.J.C. would like to thank A. Christou and J. Vaubaillon for their input on the meteor shower candidate list and M. Slipski, P. Withers and K. Peter for their insightful comments. J.M.C.P. is supported by the European Research Council (project 291332—CODITA).

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  1. Laboratory for Atmospheric and Space Physics (LASP), University of Colorado, 80303, USA

    • M. M. J. Crismani
    • , N. M. Schneider
    • , S. K. Jain
    • , M. S. Chaffin
    • , J. I. Deighan
    • , A. I. F. Stewart
    • , W. McClintock
    • , G. M. Holsclaw
    •  & B. M. Jakosky
  2. School of Chemistry, University of Leeds, Leeds LS2 9JT, UK

    • J. M. C. Plane
    •  & J. D. Carrillo-Sanchez
  3. Computational Physics, Inc., Springfield, Virginia 22151, USA

    • J. S. Evans
  4. Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721, USA

    • R. V. Yelle
  5. Center for Space Physics, Boston University, Boston, Massachusetts 02215, USA

    • J. Clarke
  6. Laboratoire de Physique Atmosphérique et Planétaire, Space sciences, Technologies and Astrophysics Research (STAR), University of Liège, B-4000 Liège, Belgium

    • A. Stiepen
  7. LATMOS/IPSL, Guyancourt 78280, France

    • F. Montmessin


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M.M.J.C., S.K.J., J.S.E., J.I.D. and M.S.C. improved the data processing to create these data products. M.M.J.C., N.M.S. and J.M.C.P. developed the interpretation of this data. J.M.C.P. and J.D.C.-S. created the model used herein. All authors contributed to the development of the instrument pipeline and/or data acquisition as well as interpretation and presentation of these results.

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The authors declare no competing financial interests.

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Correspondence to M. M. J. Crismani.

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