Probing the Atmospheric Cl Isotopic Ratio on Mars: Implications for Planetary Evolution and Atmospheric Chemistry

Giuliano Liuzzi (1, 2) , Geronimo L. Villanueva (1) , Sebastien Viscardy (3) , Daniel Mège (4) , Matteo Crismani (5) , Shohei Aoki (3, 6, 7) , Joanna Gurgurewicz (4) , Pierre‐antoine Tesson (4) , Michael J. Mumma (1) , Michael D. Smith (1) , Sara Faggi (1, 2) , Vincent Kofman (1, 2) , Elise Wright Knutsen (8) , Frank Daerden (3) , Lori Neary (3) , Frédéric Schmidt (9) , Loïc Trompet (3) , Justin T. Erwin (3) , Séverine Robert (10, 3) , Ian R. Thomas (3) , Bojan Ristic (3) , Giancarlo Bellucci (11) , Jóse Juan Lopez‐moreno (12) , Manish R. Patel (13, 14) , Ann Carine Vandaele (3)

1 GSFC - NASA Goddard Space Flight Center
2 Department of Physics [Washington]
3 BIRA-IASB - Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique
4 CBK - Space Research Centre of Polish Academy of Sciences
5 CSUSB - California State University [San Bernardino]
6 STAR - Space Sciences, Technologies and Astrophysics Research Institute
7 ISAS - Institute of Space and Astronautical Science
8 PLANETO - LATMOS
9 GEOPS - Géosciences Paris Saclay
10 IMCN - Institut de la matière condensée et des nanosciences / Institute of Condensed Matter and Nanosciences
11 IAPS - Istituto di Astrofisica e Planetologia Spaziali - INAF
12 IAA - Instituto de Astrofísica de Andalucía
13 School of Physical Sciences [Milton Keynes]
14 RAL - STFC Rutherford Appleton Laboratory

ollowing the recent detection of HCl in the atmosphere of Mars by ExoMars/Trace Gas Orbiter, we present here the first measurement of the ³⁷Cl/³⁵Cl isotopic ratio in the Martian atmosphere using a set of Nadir Occultation for MArs Discovery (NOMAD) observations. We determine an isotopic anomaly of −6 ± 78‰ compared to Earth standard, consistent with the −51‰–−1‰ measured on Mars’ surface by Curiosity. The measured isotopic ratio is also consistent with surface measurements, and suggests that Cl reservoirs may have undergone limited processing since formation in the Solar Nebula. The examination of possible sources and sinks of HCl shows only limited pathways to short‐term efficient Cl fractionation and many plausible reservoirs of “light” Cl.

Domains: Sciences of the Universe [physics]

Giuliano Liuzzi, Geronimo L. Villanueva, Sebastien Viscardy, Daniel Mège, Matteo Crismani, et al.. Probing the Atmospheric Cl Isotopic Ratio on Mars: Implications for Planetary Evolution and Atmospheric Chemistry. Geophysical Research Letters, 2021, 48 (9), pp.e2021GL092650. ⟨10.1029/2021GL092650⟩. ⟨insu-03216945⟩