Issue |
A&A
Volume 688, August 2024
|
|
---|---|---|
Article Number | A195 | |
Number of page(s) | 16 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202450384 | |
Published online | 22 August 2024 |
Study of hydrated asteroids via their polarimetric properties at low phase angles
1
Department of Physics and Astronomy, Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul
08826,
Republic of Korea
2
SNU Astronomy Research Center, Seoul National University,
1 Gwanak-ro, Gwanak-gu,
Seoul
08826,
Republic of Korea
e-mail: ishiguro@snu.ac.kr
3
Nayoro Observatory,
157-1 Nisshin, Nayoro,
Hokkaido
096-0066,
Japan
4
Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA),
Sagamihara, Kanagawa
252-5210,
Japan
5
Center for Astronomy, University of Hyogo,
407-2 Nishigaichi, Sayo,
Hyogo
679-5313,
Japan
6
Korea Astronomy and Space Science Institute (KASI),
776 Daedeok-daero, Yuseong-gu,
Daejeon
34055,
Republic of Korea
7
Department of Cosmosciences, Graduate School of Science, Hokkaido University,
Kita-ku, Sapporo
060-0810,
Japan
8
Bisei Spaceguard Center, Japan Spaceguard Association,
1716-3 Okura, Bisei-cho, Ibara,
Okayama
714-1411,
Japan
9
Asahikawa Campus, Hokkaido University of Education,
Hokumon, Asahikawa,
Hokkaido
070-8621,
Japan
10
Department of Earth Science, Faculty of Science, Tohoku University,
Aoba, Sendai,
Miyagi
980-8578,
Japan
11
Department of Physics, Okayama University of Science,
1-1 Ridai-cho, Kita-ku,
Okayama
700-0005,
Japan
Received:
15
April
2024
Accepted:
30
May
2024
Context. Ch-type asteroids are distinctive among other dark asteroids in that they exhibit deep negative polarization branches (NPBs). Nevertheless, the physical and compositional properties that cause their polarimetric distinctiveness are less investigated.
Aims. We aim to investigate the polarimetric uniqueness of Ch-type asteroids by making databases of various observational quantities (i.e., spectroscopic and photometric properties as well as polarimetric ones) of dark asteroids.
Methods. We conducted an intensive polarimetric survey of 52 dark asteroids (including 31 Ch-type asteroids) in the RC band to increase the size of polarimetric samples. The observed data were compiled with previous polarimetric, spectroscopic, and photometric archival data to find their correlations.
Results. We find remarkable correlations between these observed quantities, particularly the depth of NPBs and their spectroscopic features associated with the hydrated minerals. The amplitude of the opposition effect in photometric properties also shows correlations with polarimetric and spectral properties. However, these observed quantities do not show noticeable correlations with the geometric albedo, thermal inertia, and diameter of asteroids.
Conclusions. Based on the observational evidence, we arrive at our conclusion that the submicrometer-sized structures (fibrous or flaky puff pastry-like structures in phyllosilicates) in the regolith particles could contribute to the distinctive NPBs of hydrated asteroids.
Key words: techniques: polarimetric / minor planets, asteroids: general
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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