J/A+A/666/A77 Asteroids zero-phase angle taxonomy class (Colazo+, 2022)
Zero-phase angle taxonomy classification using unsupervised machine learning
algorithms.
Colazo M., Alvarez-Candal A., Duffard R.
<Astron. Astrophys. 666, A77 (2022)>
=2022A&A...666A..77C 2022A&A...666A..77C (SIMBAD/NED BibCode)
ADC_Keywords: Minor planets ; Colors ; Magnitudes, absolute ; Photometry, ugriz
Keywords: surveys - techniques: photometric -
minor planets, asteroids: general - method: data analysis
Abstract:
We are living in the era of large catalogs. Everyday many
observatories, terrestrial and space-based, provide us with numerous
data to do science. In this context, statistical analysis tools for
large data sets (such as Machine Learnign) play a fundamental role. An
example of such a survey is the SLOAN Moving Object Catalog (MOC),
which lists astrometric and photometric information of all moving
objects captured by the SLOAN field of view. A great advantage of this
telescope is its set of 5 filters that allows taxonomic analysis of
asteroids by studying their colors. However, until now, the color
variation produced by the change of phase angle of the object has not
been taken into account.
In this paper, we address this issue, by using absolute magnitudes for
classification. We aim to produce a new taxonomic classification of
asteroids based on their magnitudes unaffected by the magnitude
variations caused by the change in phase angle.
We selected 9481 asteroids with absolute magnitudes Hg, Hi and Hz,
computed from the SLOAN Moving Objects Catalog using the HG*12
system, and calculated absolute colors with them. To perform the
taxonomic classification, we applied a non-supervised Machine Learning
algorithm known as fuzzy C-means. This is a useful soft clustering
tool for working with overlapping data. We have decided to work with
the four main taxonomic complexes C, S, X and V as they comprise most
of the known spectral characteristics.
We classified a total of 6329 asteroids with more than 60% probability
of belonging to the assigned taxonomic class. 162 of these objects had
an ambiguous classification in the past. By analyzing the sample
obtained in the plane Semi-major axis vs. inclination, we identified
15 new V-type asteroid candidates outside the Vesta family region.
Description:
Taxonomic classification for 9781 asteroids. For each objects are
given the absolute colors Hg-Hi and Hi-Hz, spectral slope, their
respective uncertainties, final taxonomic classification, their
probability and family membership.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 185 9781 Zero-phase taxonomy
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See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Name Designation of the minor body
18- 38 F21.18 mag Hg-Hi Absolute color Hg-Hi
40- 58 F19.17 mag e_Hg-Hi Uncertainty in Hg-Hi
60- 82 E23.15 mag Hi-Hz Absolute color Hi-Hz
84-102 F19.17 mag e_Hi-Hz Uncertainty in Hi-Hz
104-126 E23.19 um-1 slope ?=- Spectral Slope
128-149 F22.20 um-1 e_slope ?=- Uncertainty in Spectral Slope
150 A1 --- neslope [I] I for infinity
152 A1 --- Cluster Cluster assignation (taxonomy)
154-172 F19.17 --- Prob Probability of membership
174-185 A12 --- Fam ?=- Family membership
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Acknowledgements:
Milagros Colazo, milagros.colazo(at)mi.unc.edu.ar
(End) Patricia Vannier [CDS] 04-Apr-2022