Monica Lazzarin

Simone Marchi

Sara Magrin

Project Description

SINEO is a spectroscopic survey of Near-Earth Objects (NEOs) in the visible and near-infrared (about 0.40-2.50 micron).

NEOs represent one of the most peculiar and heterogeneous populations in the Solar System.  These objects (which are asteroids and cometary nuclei on orbits with perihelion distances less then 1.3 AU) periodically approach or intersect the orbit of the Earth and are believed to be on the same dynamical paths which deliver meteorites to the Earth.  For this reason they pose a  non negligible risk to life on Earth. This makes the study of NEOs even more important.

The shapes of NEOs vary from nearly spherical (e.g. 1566 Icarus) to very elongated (e.g. 1620 Geographos). Radar observations and optical photometry suggest that a substantial fraction of NEOs could be binary systems (e.g. 4179 Toutatis). Lightcurve studies show that some of these objects have a complex, non-principal axis rotational state (tumbling asteroids)  while  some others display very  long rotational periods, which are not  easily explained by the  current dynamical and collisional models.

The diversity of NEOs is also reflected by the different taxonomic types present within the population: almost all the spectral classes (introduced for the main belt asteroids) have  representatives  within the NEO population. This implies a wide range of compositions, from primitive assemblages to highly differentiated objects. The majority of the classified NEOs belong to the S-class (silicate-rich) and about one tenth to the  more primitive C-class (enriched in organics). This fact indicates that the source of NEOs is predominantly located in the inner part of the main asteroid belt (i.e. where the majority of the S-types are concentrated), and is confirmed by dynamical models.

In order to address some of the several open issues concerning NEO's origin and evolution,   we started in 2000 the  SINEO spectroscopic survey  dedicated to the characterization of NEO composition. During this period, observational time has been allocated both at ESO-NTT (New Technology Telescope, La Silla, Chile) and at INAF-TNG (Telescopio Nazionale Galileo, Canary Islands) in several observing runs.

This page, which is continuously updated, is intended to provide the scientific community access to our published data.

Send comments to: webmaster - Updated April 5 2006