Issue |
A&A
Volume 389, Number 2, July II 2002
|
|
---|---|---|
Page(s) | 641 - 664 | |
Section | Celestial mechanics and astrometry | |
DOI | https://doi.org/10.1051/0004-6361:20020431 | |
Published online | 27 June 2002 |
Colors of Minor Bodies in the Outer Solar System *,**
A statistical analysis
1
European Southern Observatory, Casilla 19001, Santiago, Chile
2
Observatoire de Paris-Meudon, 5 place Jules Janssen, 92195 Meudon Cedex, France
Corresponding author: O. R. Hainaut, ohainaut@eso.org
Received:
12
October
2001
Accepted:
14
February
2002
We present a compilation of all available colors for 104 Minor Bodies
in the Outer Solar System (MBOSSes); for each object, the original
references are listed. The measurements were combined in a way that
does not introduce rotational color artifacts. We then derive the
slope, or reddening gradient, of the low resolution reflectance spectra
obtained from the broad-band color for each object.
A set of color-color diagrams, histograms and cumulative probability
functions are presented as a reference for further studies, and are
discussed. In the color-color diagrams, most of the objects are
located very close to the “reddening line” (corresponding to linear
reflectivity spectra). A small but systematic deviation is observed
toward the I band indicating a flattening of the reflectivity at
longer wavelengths, as expected from laboratory spectra. A deviation
from linear spectra is noticed toward the B for the bluer objects;
this is not matched by laboratory spectra of fresh ices, possibly
suggesting that these objects could be covered with extremely
evolved/irradiated ices. Five objects (1995 SM55, 1996 TL66, 1999 OY3, 1996 TO66 and (2060) Chiron) have almost perfectly solar colors; as two
of these are known or suspected to harbour cometary activity, the
others should be searched for activity or fresh ice signatures. In
the color-color diagrams, 1994 ES2, 1994 EV3, 1995 DA2 and 1998 HK151 are located very far from the main group of objects; it is suspected that this corresponds
to inaccurate measurements and not intrinsically strange objects.
The color distributions were analyzed as functions of the orbital
parameters of the objects and of their absolute magnitude. No
significant correlation is observed, with the following exceptions:
Cubewanos with low orbital excitation (low i, e and/or ), and therefore experiencing on average fewer
and less violent collisions have significantly redder colors;
Cubewanos with faint absolute magnitude
tend to be redder
than the others, while Plutinos present the opposite trend.
The color distribution of the various MBOSS classes are analyzed and
compared using generic statistic tools. The comets were found to be
significantly bluer than the other MBOSSes.
Finally, we compare the various 1D and 2D color distributions to
simple models, in order to throw some light on the question of the
bimodality of MBOSS color distributions. It is found that with the
current data set, all color distributions are compatible with simple,
continuous distribution models, while some color distributions are not
compatible with simple bimodal distribution models.
Table 1 is also available in electronic form at the CDS
via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/389/641, and the tables and
complete set of figures corresponding the up-to-date database are
available on the web at
http://www.sc.eso.org/~ohainaut/MBOSS.
Key words: comets: general / Kuiper Belt / solar system: general / methods: statistical
© ESO, 2002
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