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P.M. Fry, L.A. Sromovsky (University of Wisconsin - Madison)
During the period 18-21 July 1999, H- and K-band spectra of Neptune and Triton were acquired with the NSFCam HKL grism (R~290) at the NASA Infrared Telescope Facility (IRTF). Observed OH sky emission lines were used to wavelength calibrate the spectra. Vega was used as a reference star for relative flux calibration and telluric absorption correction. The spectra will be absolutely calibrated using photometry from narrow-band imaging of infrared standard stars.
Comparison of our Triton spectra with that of Quirico et al. (Icarus 139, 159-178, 1999), shows very little change since their September 1995 observatons. As expected, we were unable to discern any significant rotational modulation in the spectrum over the four nights.
Pseudo-disk-integrated spectra of Neptune were obtained by stepping the grism slit across the planet, then summing the signal to produce the resulting spectra. The spectra have higher S/N ratios than the corresponding regions of the Fink and Larson (ApJ 233, 1021-1040, 1979) spectrum.
This work was funded by NASA Planetary Astronomy Grant NAG5-12206 and HST Archive Research Grant AR-0922.01-A. We thank the NASA IRTF and our support astronomer William Vacca for their assistance.
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.