J/A+A/591/A14 PCF, SpecB or SDSSB asteroids parameters (Ali-Lagoa+, 2016)
Differences between the Pallas collisional family and similarly sized B-type
asteroids.
Ali-Lagoa V., Licandro J., Gil-Hutton R., Canada-Assandri M., Delbo M.,
de Leon J., Campins H., Pinilla-Alonso N., Kelley M.S.P., Hanus J.
<Astron. Astrophys. 591, A14 (2016)>
=2016A&A...591A..14A 2016A&A...591A..14A (SIMBAD/NED BibCode)
ADC_Keywords: Minor planets ; Photometry, infrared ; Morphology
Keywords: minor planets, asteroids: general - surveys -
infrared: planetary systems
Abstract:
B-type asteroids constitute a peculiar spectral class within the
C-complex. Previous work has pointed out the difference between the
visible geometric albedos of B-types and those of the Pallas
collisional family (PCF), whose few members with observed spectra are
B-types (one exception out of eight objects). This has been
interpreted as being due to compositional differences. However, the
PCF members are typically smaller than the spectroscopically
classified B-types, and the following possibilities have not been
ruled out: the albedo differences might be related to a size-albedo
dependence and/or to the generally larger errors of the WISE data and
best-fitting values of the derived parameters expected for smaller
objects.
We compare albedos and beaming parameters of PCF members and B-types
of similar sizes and re-examine our conclusion on the different
composition of the PCF.
By modelling their WISE/NEOWISE data, we derived sizes and albedos of
all objects whose Sloan Digital Sky Survey reflectances are similar to
the typical B-type reflectance spectra. In particular, we derived the
so-called infrared beaming parameters (eta), effective diameters (D),
and corresponding visible geometric albedos (pV), and studied their
value distributions.
Description:
The table contains the best-fitting values of size and beaming
parameter and corresponding visible geometric albedos for all our
objects. We fitted the near-Earth asteroid thermal model of Harris
(1998Icar..131..291H 1998Icar..131..291H) to WISE/NEOWISE thermal infrared data (see,
e.g., Mainzer et al., 2011ApJ...736..100M 2011ApJ...736..100M and Masiero et al.,
2014ApJ...791..121M 2014ApJ...791..121M). Minimum relative errors of 10, 15, and 20
percent should be considered for size, beaming parameter and albedo in
those cases for which the beaming parameter could be fitted.
Otherwise, a default value of the beaming parameter is assumed (its
negative value is given in the table) and the minimum relative errors
in size and albedo increase to 20 and 40 percent (see, e.g., Mainzer
et al., 2011ApJ...736..100M 2011ApJ...736..100M).
We also provide the asteroid absolute magnitudes and slope parameters
retrieved from the Minor Planet Center (MPC), the number of
observations used in each WISE band (W3 and W4), plus the
corresponding average values of heliocentric and geocentric distances
and phase angle (r, g, a) based on the ephemerides taken from the
MIRIADE service (http://vo.imcce.fr/webservices/miriade/?ephemph). The
subsample label indicates whether the object belongs to the SDSS,
spectroscopic B or PCF groups. Labels with the suffix 'qA' indicate
that only data with signal-to- noise ratio greater than 10 were used
for that case (see Appendix A of the article for more details).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 69 1468 *Best-fitting values of size and infrared beaming
parameter and corresponding geometric visible
albedos for our objects
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Note on table1.dat: We include objects in the Pallas collisional family (PCF),
spectroscopic B- types (SpecB) and B-types (SDSSB) according to their SDSS
reflectances and the selection procedure of Assandri & Gil-Hutton
(2008A&A...488...339A).
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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- 5 A5 --- d Asteroid designation (MPC-packed format)
7- 11 F5.2 mag H Asteroid absolute magnitude (MPC)
13- 16 F4.2 --- G Slope parameter (MPC)
18- 22 F5.1 km D Equivalent diameter
25- 28 F4.2 --- pV Visible geometric albedo
31- 34 F4.1 --- eta Infrared beaming parameter
38- 39 I2 --- W3 Number of data fitted in band W3
41- 42 I2 --- W4 Number of data fitted in band W4
46- 50 F5.3 AU r Average heliocentric distance
52- 56 F5.3 AU g Average geocentric distance
58- 61 F4.1 deg a Average phase angle
63- 69 A7 --- L Group label (PCF, SpecB or SDSSB)
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Acknowledgements:
Victor Ali-Lagoa, vmalilagoa(at)gmail.com
(End) Victor Ali-Lagoa [OCA, Nice, France], Patricia Vannier [CDS] 05-Apr-2016