J/A+A/607/A103 Main-belt asteroids polarimetry. VI. (Gil-Hutton+, 2017)
Polarimetric survey of main-belt asteroids.
VI. New results from the second epoch of the CASLEO survey.
Gil-Hutton R., Garcia-Migani E.
<Astron. Astrophys. 607, A103 (2017)>
=2017A&A...607A.103G 2017A&A...607A.103G (SIMBAD/NED BibCode)
ADC_Keywords: Minor planets ; Polarization
Keywords: minor planets, asteroids: general - techniques: polarimetric
Abstract:
We present the results of a polarimetric survey of main-belt asteroids
at Complejo Astronomico El Leoncito (CASLEO), San Juan, Argentina.
The aims of this survey are to increase the database of asteroid
polarimetry and to estimate the diversity in the polarimetric
properties of asteroids that belong to different taxonomic classes.
The data were obtained using the CASPOL polarimeter at the 2.15 m
telescope. CASPOL is a polarimeter based on a CCD detector and a
Savart plate. The survey began in 1995 and data on a large sample of
asteroids were obtained until 2012. A second period began in 2013
using a polarimeter with a more sensitive detector in order to study
small asteroids, families, and special taxonomic groups.
We present and analyze the unpublished results for 128 asteroids of
different taxonomic types, 55 of them observed for the first time. The
observational data allowed us to find probable new cases of Barbarian
objects but also two D-type objects, (565) Marbachia and (1481)
Tubingia, that seem to have phase-polarization curves with a large
inversion angle. The data obtained combined with data from the
literature enabled us to find phase-polarization curves for 121
objects of different taxonomic types and to study the relations
between several polarimetric and physical parameters. Using an
approximation for the phase-polarization curve we found the index of
refraction of the surface material and the scatter separation distance
for all the objects with known polarimetric parameters. We also found
that the inversion angle is a function of the index of refraction of
the surface, while the phase angle where the minimum of polarization
is produced provides information about the distance between scatter
particles or, to some extent, the porosity of the surface.
Description:
Results of the second epoch of the polarimetric survey of main-belt
objects at Complejo Astronomico El Leoncito (CASLEO), San Juan,
Argentina.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 79 171 Polarimetric data for the asteroids observed
table2.dat 86 121 Values of n and kd for asteroids
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See also:
B/astorb : Orbits of Minor Planets (Bowell+ 2014)
J/A+A/539/A115 : Main-belt asteroids polarimetry. II. (Gil-Hutton+, 2012)
J/A+A/542/A11 : Main-belt asteroids polarimetry. III (Canada-Assandri+, 2012)
J/A+A/569/A122 : Main-belt asteroids polarimetry. IV (Gil-Hutton+, 2014)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Name Asteroid name
24- 33 A10 "date" Obs.Date UT observation date
35- 38 I4 s Tint Total integration time
40- 43 F4.1 deg alpha Phase angle
45- 49 F5.1 deg thetasun Position angle of the scattering plane
51- 54 F4.2 % P Observed polarization
56- 59 F4.2 % e_P Error in observed polarization
61- 65 F5.1 deg theta Position angle in the equatorial
reference frame
67- 70 F4.1 deg e_theta Error in position angle in the equatorial
reference frame
72- 76 F5.2 % Pr Reduced polarization
78- 79 A2 --- Tax Bus taxonomic classification
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 22 A22 --- Name Asteroid name
23- 27 F5.2 deg alphamin Phase angle of the minimum of the
phase-polarization curve
29- 32 F4.2 deg e_alphamin Error in phase angle of the minimum of the
phase-polarization curve
34- 39 F6.3 % Pmin Minimum of the phase-polarization curve
41- 45 F5.3 % e_Pmin Error in the minimum of the
phase-polarization curve
47- 51 F5.2 deg alpha0 Inversion angle
53- 56 F4.2 deg e_alpha0 Error in inversion angle
58- 63 F6.4 %/deg h Slope at the inversion angle
65- 70 F6.4 %/deg e_h Error in slope at the inversion angle
72- 76 F5.3 --- n Refractive index
78- 83 F6.3 --- kd Wave number times the scatter separation
85- 86 A2 --- Tax Bus taxonomic classification
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Acknowledgements:
Ricardo Gil-Hutton, ricardo.gil-hutton(at)conicet.gov.ar
GCP, FCEFN, UNSJ-CONICET, Argentina
References:
Gil-Hutton & Canada-Assandri, Paper I 2011A&A...529A..86G 2011A&A...529A..86G
Gil-Hutton & Canada-Assandri, Paper II 2012A&A...539A.115G 2012A&A...539A.115G Cat. J/A+A/539/A115
Canada-Assandri et al. , Paper III 2012A&A...542A..11C 2012A&A...542A..11C Cat. J/A+A/542/A11
Gil-Hutton et al., Paper IV 2014A&A...569A.122G 2014A&A...569A.122G Cat. J/A+A/569/A122
Gil-Hutton et al., Paper V 2017A&A...599A.114G 2017A&A...599A.114G
(End) R. Gil-Hutton [UNSJ-CONICET, Argentina], P. Vannier [CDS] 12-Oct-2017