![\begin{figure}
\par\includegraphics[width=7.5cm,clip]{9130fig1.eps} %
\end{figure}](/articles/aa/full/2008/09/aa9130-07/img18.gif) |
Figure 1:
Snapshot of R band images acquired during each night of our
observing run, showing the evolution of
comet 17P/Holmes' morphological structure.
Each image has been scaled to the
same exposure time, airmass, and intensity range
and
displayed on a logarithmic color scale, codified by the bottom
color bar. The top 6 images are zoomed inside the inner
regions of the object and have a field of view of
 arcmin, whereas
the last one  arcmin.
Two cores are visible in all the images, the comet
nucleus (on the upper left side) and the core of
the coma, rapidly separating
during the observing period.
The values reported for the
coma's innermost isophotes of each
panel (or in the close-up views of 28/29/31 nights) show
the surface brightness decrement of the coma due
to its rapid expansion.
|
| Open with DEXTER | |
In the text
![\begin{figure}
\par\includegraphics[width=4cm,clip]{9130fg2a.eps}\hspace*{4mm}
\includegraphics[width=4cm,clip]{9130fg2b.eps} %
\end{figure}](/articles/aa/full/2008/09/aa9130-07/img26.gif){kind=small} |
Figure 2:
Left: angular projected distance between the
centroid of the two bright baricenters, for all the images in our
dataset, against the 
of
the observations. The continuous line denotes the best fit linear
model. On the left hand y-axis values are in arcsec, whereas
on the right hand y-axis values are in km.
Right:
of the expanding cloud
Gaussian core against .
Different colors indicate
measurements obtained in different bands: B in black, V in
blue, R in red and I in yellow. The best fit linear
models in each band are represented by the continuous lines.
|
| Open with DEXTER | |
In the text
![\begin{figure}
\par\includegraphics[width=4.2cm,clip]{9130fg3a.eps}\hspace*{2mm}...
...} \includegraphics[width=6.5cm,clip]{9130fg3c.eps}\hspace*{1cm}}
%
\end{figure}](/articles/aa/full/2008/09/aa9130-07/img31.gif) |
Figure 3:
Top: spatial distribution of the 20 background stars
used in Sect. 5 to probe the differential
extinction produced by the coma, for the two images acquired on
October 28, 2007. The image on the left was taken 2 h before
the right one.
The selected stars are
indicated by white circles. The associated numeration
corresponds to the one in the lower panel,
allowing each star to be related to the correspondent
measured differential extinction.
Bright sources were saturated
(black regions), as well as was the center of the cometary nucleus.
The black lines indicate the distances, referred to in
Sect. 5 as r1 and r2, of
one star with respect to the
estimated coma's centers.
Bottom: the correlation between the differential extinctions in
the R band ( )
and the x parameter
(see text for details).
|
| Open with DEXTER | |
In the text