# # Program information file # PROGRAM_ID 2021A098 PROGRAM_TITLE Spectral characterization of small binary asteroids PROGRAM_INV1 Myriam Pajuelo PROGRAM_INV2 Mirel Birlan PROGRAM_INV3 Benoit Carry PROGRAM_INV4 Francesca DeMeo PROGRAM_INV5 Jerome Berthier PROGRAM_SCICAT solar system PROGRAM_ABSTRACT_BEG Binary systems represent a unique opportunity to determine asteroid densities, a property that is fundamental in understanding their bulk composition. Determination of their surface composition is however required to study their internal structure and collision history. Only the comparison of an asteroid density with that of its constituents tell us about its interior. We propose here to observe binary asteroids with unknown spectral classification to determine their composition for the first time. For that purpose, we will use upgraded SpeX [Rayner et al, 2003] in the Prism low-resolution mode with the 0.8x15 arcsec slit, in order to cover the spectral interval 0.8-2.5um. Experience/Simulation shows that an SNR of 40 is required to detect the near-IR absorption bands of the minerals present on asteroid surfaces. A V=17.0 mag target will need ~ 40 minutes of total integration time in order to get the required SNR. Our observations will greatly benefit from the use of MORIS, which will help us into a better tracking of the target, thus increasing the SNR value. We will intersperse our asteroid measurements with those of a nearby solar-type SAO/HD stars to monitor and correct any short-term fluctuations in atmospheric conditions. These frequent standard and comparison star observations will also optimize the precision removal of telluric features. PROGRAM_ABSTRACT_END