J/A+A/546/A86 R absolute magnitudes of Kuiper Belt objects (Peixinho+, 2012)
The bimodal colors of Centaurs and small Kuiper belt objects.
Peixinho N., Delsanti A., Guilbert-Lepoutre A., Gafeira R., Lacerda P.
<Astron. Astrophys. 546, A86 (2012)>
=2012A&A...546A..86P 2012A&A...546A..86P
ADC_Keywords: Solar system ; Minor planets ; Colors
Keywords: Kuiper belt: general
Abstract:
Ever since the very first photometric studies of Centaurs and Kuiper
belt objects (KBOs) their visible color distribution has been
controversial. This controversy has triggered a prolific debate on the
origin of the surface colors of these distant icy objects of the solar
system. Two scenarios have been proposed to interpret and explain the
large variability of colors, hence surface composition. Are the colors
mainly primordial and directly related to the formation region, or are
they the result of surface evolution processes? To date, no mechanism
has been found that successfully explains why Centaurs, which are
escapees from the Kuiper belt, exhibit two distinct color groups,
whereas KBOs do not. We re-address this issue using a carefully
compiled set of B-R colors and HRα magnitudes (as proxy
for size) for 253 objects, including data for 10 new small objects. We
find that the bimodal color distribution of Centaurs is a size-related
phenomenon, common to both Centaurs and small KBOs, i.e. independent
of dynamical classification. Furthermore, we find that large KBOs also
have a bimodal distribution of surface colors, albeit distinct from
the small objects and strongly dependent on the `Haumea collisional
family' objects. When plotted in B-R, HRα space, the
colors of Centaurs and KBOs display a peculiar N shape.
Description:
Compilation of absolute magnitude HRα, B-R colors, and
spectral features used in this work. For each object, we computed the
average color index from the different papers presenting data obtained
simultaneously in B and R bands (e.g. contiguous observations
within a same night). When individual R apparent magnitude and date
were available, we computed the HRα=R-5log(r Delta),
where R is the R-band magnitude, r and Delta are the helio- and
geocentric distances at the time of observation in AU, respectively.
When V and V-R colors were available, we derived an R and then
HRα value. We did not correct for the phase-angle α
effect. This table includes also spectral information on the presence
of water ice, methanol, methane, or confirmed featureless spectra, as
available in the literature. We highlight only the cases with clear
bands in the spectrum, which were reported/confirmed by some other
work. The 1st column indicates the object identification number and
name or provisional designation; the 2nd column indicates the
dynamical class; the 3rd column indicates the average HRα
value and 1-σ error bars; the 4th column indicates the average
$B-R$ color and 1-σ error bars; the 5th column indicates the most
important spectral features detected; and the 6th column points to the
bibliographic references used for each object.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 119 253 Compilation of R-band absolute magnitude, not
corrected for the phase-angle, of B-R colors,
and spectral features of 253 Centaurs and KBOs
(Kuiper Belt Objects)
table3.tex 163 272 LaTeX version on table3
refs.dat 99 59 References
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- Planet ? Asteroid number (blank if unnumbered)
8- 20 A13 --- Name Name or preliminary designation
22- 46 A25 --- Class Dynamical class (1)
49- 55 F7.3 mag RMag R-band absolute magnitude HRα,
not corrected for the phase-angle
58- 62 F5.3 mag e_RMag 1-σ error bar of Rmag
64- 70 F7.3 mag B-R B-R color index
73- 77 F5.3 mag e_B-R 1-σ error bar of B-R color
80- 90 A11 --- SpecF Spectral features which have been clearly
identified
93-119 A27 --- Refs Pointer for bibliographic references with
measurements and detections that have been
used, in refs.dat file
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Note (1): Dynamical classes (explained in Appendix A of the paper) as follows:
Centaur = the objects with orbits between those of Jupiter and Neptune
Cold classical = objects with rather circular orbits beyond Neptune and
below the 2:1 resonance region (being called Cold if their
orbital inclination is lower than 5°)
Hot classical = objects with rather circular orbits beyond Neptune and
below the 2:1 resonance region (being called Hot if their
orbital inclination is higher than 5°)
Detached KBO = objects beyond past or future gravitational influence by
Neptune
Neptune Trojan = object located in 1:1 mean motion resonance with Neptune
Plutino = object located in 3:2 mean motion resonance with Neptune
Resonant (N:N) = objects orbiting in mean motion resonances with Neptune
Scattered disk object = objects within probable gravitational influence of
Neptune (SDO)
Scattered or detached KBO = Scattered disk object or Detached KBO
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Ref Reference code
4- 22 A19 --- BibCode CDS/ADS bibcode
24- 44 A21 --- Aut Author's name
46- 99 A54 --- Com Comments
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Acknowledgements:
Nuno Peixinho, peixinho (at)mat.uc.pt
(End) N. Peixinho [CGUC, Unic. Coimbra, Portugal], P. Vannier [CDS] 26-Jun-2012