Geoscience Reference
In-Depth Information
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size (km)
Fig. 3. The fraction (in %) of existing Main Belt asteroids whose sizes will be measured
at least once with an accuracy better than 10% as a function of size, during the 5 years
operational lifetime of Gaia.
An alternative way to present the results of these simulations, is given in
Fig. 3, in which we take also into account the results of detailed simula-
tions (performed by F. Mignard) of the actual detections of known main
belt asteroids in a simulated Gaia survey lasting 5 years (starting since a
given simulated starting date, which is not relevant for the present pur-
poses). In particular, Fig. 3 shows, as a function of the linear sizes of the
objects (in km) the fraction (in %) of the real asteroids of that size that
will be measured with an accuracy better than 10% at least once during
the operational lifetime of the mission.
The results of the simulations show that above 30 km in diameter, more
than one half of the known main belt asteroids will have their size measured
at least once during the Gaia operational lifetime. The number of useful
measurements rapidly increases for increasing size. Between 20 and 30 km,
a fraction larger than 20% of the objects will also be measured at least
once, or even a few times. The number of objects that will be measured
is thus of the order of 1,000. These results will have a tremendous impact
on our knowledge of the asteroid population, as will be discussed in Sec. 5.
Here, we only stress the fact that such a result will not be possible using
any other observing facility existing today or planned to be operative in
the next 10 years.
