J/MNRAS/456/248 (4) Vesta adopted polarimetric light curves (Cellino+, 2016)
The Dawn exploration of (4) Vesta as the "ground truth" to interpret asteroid
polarimetry.
Cellino A., Ammannito E., Magni G., Gil-Hutton R., Tedesco E.F.,
Belskaya I.N., De Sanctis M.C., Schroder S., Preusker F., Manara A.
<Mon. Not. R. Astron. Soc., 456, 248-262 (2016)>
=2016MNRAS.456..248C 2016MNRAS.456..248C (SIMBAD/NED BibCode)
ADC_Keywords: Minor planets ; Polarization
Keywords: methods: data analysis - techniques: polarimetric -
minor planets, asteroids: individual: (4) Vesta
Abstract:
The results of the in situ exploration of the asteroid (4) Vesta by
the Dawn spacecraft open new perspectives in the field of interpretation
of remote-sensing polarimetric measurements of asteroids. (4) Vesta has
long been known to be the only asteroid exhibiting a cyclic variation
of the degree of linear polarization of the sunlight scattered by its
surface, with a period which is synchronous with the object's rotation.
This variation must be the consequence of some heterogeneity of the
asteroid's surface, including regions characterized by different albedo,
or composition, or regolith properties, or a combination of the above
features. For a long time, this kind of conclusion has remained essentially
qualitative. Now, after the extensive exploration of Vesta's surface
by Dawn, it is possible to interpret the data set of polarimetric
measurements of Vesta, including some unpublished data presented here
for the first time, in terms of a correspondence between the degree of
linear polarization and the variation of local properties of the surface
visible to ground-based observers during Vesta's rotation, as seen at
different epochs and under different illumination conditions. This makes
it possible to refine our knowledge of the empirical relation between
polarization properties and albedo, which is commonly used to derive
the albedo from remote-sensing measurements of linear polarization of
atmosphereless Solar system bodies.
Description:
The first polarization light curves of Vesta were obtained on 1977
February 13 and 14, and 1978 July 24, 25 and 26. The 1977 data were
obtained with a 1-m University of Arizona telescope and the 1978 with
a 1.51-m University of Arizona telescope. Another couple of more recent
polarimetric light curves are available in the literature. They were
obtained on 1986 September 7, and published by Lupishko et al.
(1988AVest..22..142L 1988AVest..22..142L). Another polarimetric light curve was obtained
on 1988 Feb 16, 20 and 22 by Manara & Broglia (1989A&A...214..389B 1989A&A...214..389B).
To these, we also add now a new polarimetric light curve obtained during
the night between 2011 September 25 and 26 using the 2.15-m telescope
of the El Leoncito Observatory (Argentina).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 35 223 The polarimetric light curves adopted in
this work
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See also:
J/A+A/623/A6 : VLT/SPHERE/ZIMPOL images of Vesta (Fetick+, 2019)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 5 F5.1 deg LatSE [-22.1/21.6] Latitude of the sub-Earth point
at the epoch of observation
7- 12 F6.1 deg LongSE [-178.5/351.3] Longitude of the sub-Earth point
at the epoch of observation
14- 19 F6.3 % Pr [-0.563/0.22] Degree of linear polarization
21- 25 F5.3 --- pVmean [0.274/0.34] Average albedo of the visible
hemisphere
27- 30 F4.1 deg alpha [10.7/21.5] Phase angle α
32- 35 I4 --- Year [1977/2011] Year of observation
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History:
From electronic version of the journal
(End) Tiphaine Pouvreau [CDS] 13-Feb-2020