J/A+A/686/A76 0.7um band parameters primitive asteroids (Tinaut-Ruano+, 2024)
Asteroid reflectance spectra from Gaia DR3: near-UV in primitive asteroids.
Tinaut-Ruano F., de Leon J., Tatsumi E., Morate D., Mahlke M., Tanga P.,
Licandro J.
<Astron. Astrophys. 686, A76 (2024)>
=2024A&A...686A..76T 2024A&A...686A..76T (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; Minor planets ; Spectroscopy ; Ultraviolet
Keywords: instrumentation: spectrographs - methods: observational -
methods: statistical - techniques: spectroscopic - catalogs -
minor planets, asteroids: general
Abstract:
In the context of charge-coupled devices (CCDs), the ultraviolet (UV)
region has mostly remained unexplored after the 1990s. Gaia DR3 offers
the community a unique opportunity to explore tens of thousands of
asteroids in the near-UV as a proxy of the UV absorption. This
absorption has been proposed in previous works as a diagnostic of
hydration, organics, and space weathering.
In this work, we aim to explore the potential of the NUV as a
diagnostic region for primitive asteroids using Gaia DR3.
We used a corrective factor over the blue part of Gaia spectra to
erase the solar analog selection effect. We identified an artificial
relation between the band noise and slope and applied a
signal-to-noise ratio (S/N) threshold for Gaia bands. Meeting the
quality standards, we employed a Markov chain Monte Carlo (MCMC)
algorithm to compute the albedo threshold, maximizing primitive
asteroid inclusion. Utilizing one- and two-dimensional (1D and 2D)
projections, along with dimensionality-reduction methods (such as PCA
and UMAP), we identified primitive asteroid populations.
We uncovered: (a) the first observational evidence linking UV
absorption to the 0.7um band, tied to hydrated iron-rich
phyllosilicates; and (b) a 2D space revealing a split in C-type
asteroids based on spectral features, including UV absorption. The
computed average depth (3.5±1.0%) and center (0.70±0.03um) of
the 0.7um absorption band for primitive asteroids observed with Gaia
is in agreement with the literature values.
In this paper, we shed light on the importance of the UV absorption
feature to discriminate among different mineralogies (i.e., iron-rich
phyllosilicates vs. iron-poor) or to identify taxonomies that are
conflated in the visible (i.e., F-types vs. B-types). We have shown
that this is a promising region for diagnostic studies of the
composition of primitive asteroids.
Description:
In this table we share with the community the obtained parameters
for the 0.7 micron band, such as, depth, central wavelength and 1
sigma width. We tried to fit the model to all the primitive objects
selected from Gaia DR3. Computations that resulted in 1 sigma smaller
than 0.035 microns or exceed 0.085 microns were not considered. This
choice avoid the overfitting between Gaia spectral bands and the
fitting curvature of the continuum. For further information see paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 96 15474 0.7 micron band parameters primitive asteroids
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See also:
I/359 : Gaia DR3 Part 5. Solar System (Gaia Collaboration, 2022)
B/astorb : Orbits of Minor Planets (Bowell+, 2014-)
Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- MPC Number ID following MPC nomenclature
8- 30 F23.20 um-1 s ? Slope of the continuum, m in Eq. 1.
32- 53 F22.19 % depth ? Band depth, d in Eq. 1.
55- 75 F21.18 um wc ? Central wavelength, λc in Eq. 1.
77- 96 F20.18 um sigma ? Band width, σ in Eq. 1.
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Acknowledgements:
Fernando Tinaut-Ruano, ftinaut(at)iac.es
(End) Patricia Vannier [CDS] 06-Mar-2024