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NICS-TNG Obtain the first infrared spectra of trans-neptunian objects ever done with a 4m class telescope.


Complete near-infrared (0.9-2.4 microns) spectral observations of trans-neptunian objects (TNOs) 2000 WR106 (actually named 20000 VARUNA) and 2000 EB173 were done using the Near Infrared Spectrograph (NICS) low-dispersion - high throughput spectroscopic mode with an Amici prism disperser. TNOs spectra togheter with the reflectance spectrum of 10 microns water ice particles at 90 K are shown in the figure. Both spectra correspond to very red objects. The spectrum of 2000 WR106 has quite deep water ice absorption features at 1.5 and 2.0 microns.
TNOs are the most pristine objects of the solar system and probably contain some of the least modified materials remaining from the protosolar nebula. The study of the physical properties and evolution of their surface is very important from a comsogonical point of view.

Until now there are only 4 published infrared spectra of TNOs, all done with the Keck telescope and covering a much more limited spectral range.
These are the first TNOs infrared spectra ever obtained with a 4m class telescope, note that the two objects had J = 18.2 - 18.5 mag when observed. More details can be found in a paper recently accepted for publication in Astronomy & Astrophysics Letters (astro-ph/0105434).