Title  Mapping the surfaces of larger asteroids
Pi     B. Butler
Time   105 hrs

Title: Mapping the surfaces of larger asteroids
Authors: B. Butler

Abstract: The larger main belt asteroids can be mapped in a
   way similar to the terrestrial planets, yielding similar
   information (see that abstract).  Information on the 
   structure of the surface and near-surface will help
   constrain the formation history of these bodies.  This 
   kind of observation will also be a requirement for using 
   these bodies (those with diameter >~ 200 km) as secondary 
   calibrators, as their brightness distribution (or at the 
   very least their millimetric light curve) will have to be 
   well known.

                                                                         contin          line        poln
name   RA&DEC   m T SD CA sub resn size freq   line   dfreq      BW    fd       rms    fd    rms   fd    rms   time
----  --------  - - -- -- --- ---- ---- ----  ------ --------  -----  --------------  -----------  ---------  ------
MBA   ecliptic  Y Y N  N   N   .05 .1-1  345    N/A    N/A     8 GHz  ~100 K    1 K       N/A      3 K  .1 K  60x1 h
MBA   ecliptic  Y Y N  N   N   1   .1-1   90    N/A    N/A     8 GHz  ~100 K    1 K       N/A      3 K  .1 K  15x1 h
MBA   ecliptic  Y Y N  N   N   1   .1-1  230    N/A    N/A     8 GHz  ~100 K    1 K       N/A      3 K  .1 K  15x1 h
MBA   ecliptic  Y Y N  N   N   1   .1-1  650    N/A    N/A     8 GHz  ~100 K    1 K       N/A      3 K  .1 K  15x1 h
total                                                                                                         105 h

Note: In an hour, you can do about 10 of the mapping obsns, 
   as the sensitivity in 5 minutes is enough to get 1 K.  With
   roughly 150 of these bodies, and 4 or so observations for
   each of them for full surface coverage, that gives about
   60 1 hour sessions.

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See program 4.1.1. for general comments Butler and Gurwell

Review Mark Gurwell: : 
       I am not sure why the 90, 230 and 650 observations are all at much
       coarser resolution compared to 345. I would suggest similar
       resolution at at least 90 GHz to the 345 GHz.

Reply Butler:
The 345 GHz ones were mapping - the others were light curves.  I
didn't make that very clear.  In principle,
they could all be high resolution and the light curve drops out
of the mapping naturally - I just wanted to distinguish between
the two types of observations.



--------------------------------------------------
Review v2.0:
 
Review of 4.2.1-4.2.8 (no DRSP 2.0 updates received)

These projects still remain scientifically valid. Do the additional
ALMA bands offer something new (e.g., for projects 4.2.4, 4.2.5)? The
integration times are probably still ok eventhough the number of
antennas has gone from 64 to 50 - or at least close enough.

Several of these projects focus on objects larger than the ALMA
primary beam, and mosaicing is needed. Here the ACA and also the ACA
in crosscorrelation with the ALMA-12m antennas may be beneficial.