Geoscience Reference
In-Depth Information
THE EXPECTED ROLE OF GAIA FOR
ASTEROID SCIENCE
ALBERTO CELLINO
∗,‡
, ALDO DELL'ORO
∗,§
and PAOLO TANGA
†,¶
∗
INAF — Osservatorio Astronomico di Torino
I-10025 Pino Torinese (TO), Italy
†
Observatoire de la Cote D'Azur
B.P. 4229 06304 Nice Cedex 4, France
‡
cellino@to.astro.it
§
delloro@to.astro.it
¶
tanga@obs-nice.fr
According to current plans of ESA, Gaia will be launched in 2011. With a sys-
tematic survey of the whole sky down to magnitude
V
= 20, Gaia will provide
a fundamental contribution in practically all fields of modern Astrophysics.
In particular, Gaia will be also a major milestone in the history of asteroid
science. Based on its unprecedented astrometric performances, complemented
by spectroscopic and photometric capabilities, Gaia will be able to measure
the masses of about 100 asteroids. It will directly measure sizes of about 1,000
objects, will derive spin properties and overall shapes of about 10,000 objects,
and will derive much improved orbits and taxonomic classification of hundreds
of thousands asteroids. The post-Gaia era in asteroid science will be one in
which we will know average densities of about 100 objects belonging to all the
major taxonomic classes, we will have a much more precise knowledge of the
inventory and size and spin distributions of the population, of the distribution
of taxonomic classes as a function of heliocentric distance, and of the dynamical
and physical properties of dynamical families.
1. Introduction
In some respect, the exploration of the asteroids by means of
in situ
explo-
ration by space probes seems to be an endless adventure. The reason is
that in spite of impressive results that have been obtained in recent years
after some successful space missions (Galileo, Stardust, NEAR-Shoemaker,
and currently Hayabusa) it is clear that there is no hope to have in the
near future a number of missions sucient to explore all the large variety
of physical properties (in terms of sizes, compositions, structures, thermal,
collisional, and dynamical histories) which characterize this vastly hetero-
geneous population of minor bodies. At the same time, it is also true
that, apart from a handful of objects that are fairly well known due to
299
