(Proposal ID) S11A-111

(PI) Yagi, Masafumi

(Proposal Title)
Slitless spectroscopy of small bodies on a dark cloud curtain

(Abstract)
We propose a slitless spectroscopy of minor bodies in the solar system of 
R < 23, which corresponds to > 0.2-0.7 km size at the main belt using Suprime-
Cam and grism filters. The merit of slitless spectroscopy is that we can 
detect a minor body and take its spectrum in a single observation. We can 
therefore avoid the prior orbit determination, which made the spectroscopy of 
faint moving objects difficult. In our 2009A observation, we obtained 50 
spectra in a night, and in 2010A observation, we obtained 40 spectra in a 
night. Our method to use a Galactic dark cloud to shade extragalactic objects 
is also proven to be very effective. However, the S/N of the faint moving 
object are insufficient for type classification. We therefore propose to add 
more than 50 spectra of R < 23 moving objects with S/N>10 using 3 nights. The 
data is enough to make a statistical comparison of the spectroscopic type 
distribution of < 5km size MBAs with that of well-studied near earth objects. 
Also, we request 0.5 night of follow-up observation for newly detected TNOs.