Open AccessChemical markers of possible hot spots on Mars
Author(s) -
Wong AhSan,
Atreya Sushil K.,
Encrenaz Thérèse
Publication year - 2003
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002je002003
Subject(s) - outgassing , mars exploration program , astrobiology , methane , martian , atmosphere (unit) , atmosphere of mars , volatiles , hydrogen sulfide , carbon dioxide , halogen , sulfur , environmental science , geology , chemistry , mineralogy , physics , meteorology , alkyl , organic chemistry
Although there is no evidence of active volcanism on Mars today, “localized” outgassing sources, the hot spots, may not be ruled out. If outgassing does occur somewhere on Mars, water, carbon dioxide, sulfur species, methane, and to a lesser extent, halogens would be the likely molecules of outgassing, based on terrestrial analogs. The sulfur species, methane, and halogens have not been detected in the Martian atmosphere, but the observations were averaged over large areas, which could result in substantial dilution in abundances. If the interpretation of certain Mars Global Surveyor images indicating recent ground water seepage and surface runoff [ Malin and Edgett , 2000] is correct, it may imply that Mars could still be active internally in some places from time to time, and outgassing of the abovementioned species may occur with or without the water seepage. Moreover, if the tentative detection of formaldehyde (CH 2 O) in the equatorial region of Mars [ Korablev et al. , 1993] is confirmed by future observations, it would imply at least local outgassing of methane, whose oxidation results in the formation of CH 2 O. Considering the possibility of outgassing from some localized hot spots, we have developed a one‐dimensional photochemical model that includes methane (CH 4 ), sulfur dioxide (SO 2 ), and hydrogen sulfide (H 2 S), starting with their current “global average” upper limits of 0.02, 0.1, and 0.1 ppm at the surface, respectively, and then progressively increasing their abundances above possible hot spots. We find that the introduction of methane into the Martian atmosphere results in the formation of mainly formaldehyde, methyl alcohol (CH 3 OH), and ethane (C 2 H 6 ), whereas the introduction of the sulfur species produces mainly sulfur monoxide (SO) and sulfuric acid (H 2 SO 4 ). The effect of outgassed halogens on the Martian atmosphere is found to be negligible. Depending upon the flux of outgassed molecules from possible hot spots, some of these species and the resulting new molecules may be detectable locally, either by remote sensing or in situ measurements.