spectra by those of HR 8545 and multiplied by a blackbody radiation curve of the G3V star temperature, which is equivalent to simultaneous flat fielding and atmospheric opacity correction. G stars, however, have numerous intrinsic (absorption) feautres, so that this procedure could inflate the intensities of emission lines if they fall on these stellar features. We have estimated the errors using the G2V solar spectrum [@liv91][^2] as a template of our reference star HR 8545 [cf. @mai96; @vac03]. The estimated errors in the observed line fluxes are $\le 5$% for all lines except line for which it is $10$%. The resulting errors in the line ratios, which are used for the derivation of physical parameters, are $\le 2$% except for the /164 ratio for which it is 7%. These calibration errors are all less than their statistical ($1\sigma$) errors (see Table 2). Another source of error is different atmospheric condition. All spectra of the source and HR 8545 were obtained at air mass of 1.6–1.8 except the H$_2$ spectra of the source which was obtained at an air mass of 2.27. There is a strong atmospheric CO$_2$ absorption line between 2.05 and 2.08 $\mu$m, and the different airmasses can give 