  The protonated form of CO2, HOCO+, is assumed to be an indirect tracer of CO2
in the millimeter/submillimeter regime since CO2 lacks a permanent dipole
moment. Here, we report the detection of two rotational emission lines (4 0,4-3
0,3) and (5 0,5-4 0,4) of HOCO+ in IRAS 16293-2422. For our observations, we
have used EMIR heterodyne 3 mm receiver of the IRAM 30m telescope. The observed
abundance of HOCO+ is compared with the simulations using the 3-phase NAUTILUS
chemical model. Implications of the measured abundances of HOCO+ to study the
chemistry of CO2 ices using JWST-MIRI and NIRSpec are discussed as well.
