(Proposal ID) S12A-060

(PI) Aoki, Shohei

(Proposal Title)
Search of CH4 around the mud volcanism areas on Mars

(Abstract)
We propose the first measurement of CH4 specialized in the mud volcanism areas 
on Mars. Although the small amount of CH4 in the Martian atmosphere is 
remarkable because its source is potentially geological (or biological) 
activity, it is still open question. The high spectral and spatial resolution 
with high sensitivity and wide spectral coverage of IRCS/Subaru enable us the 
first mapping of CH4 on the localized mud volcanism areas. In the terrestrial 
case, mud volcanism vents about 25% of CH4 released from geological sources to 
the atmosphere. In such locations, CH4 can potentially combine with the 
infiltrated H2O and generate CH4-hydrate. While in the Martian case, the mud 
volcanism is expected the mounds in Acidalia Planitia and the Utopia/Isidis 
pitted cones. However, the releases of CH4 on these locations have not been 
discovered yet. Since the CH4-hydrate suggests the correlation of CH4 and H2O, 
high spatial resolution with simultaneous measurements of CH4 and H2O lines 
are essential. IRCS/Subaru can provide this opportunity. In addition, our 
observation will override the past one with CSHELL/IRTF in the following 
aspects, (1) less uncertainty by simultaneous measurement of multiple CH4 
lines with wider spectral coverage, and (2) better spatial resolution.