Volume 625, May 2019
|Number of page(s)||40|
|Section||Planets and planetary systems|
|Published online||28 May 2019|
Thermal properties of slowly rotating asteroids: results from a targeted survey★
Astronomical Observatory Institute, Faculty of Physics, A. Mickiewicz University,
2 Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany
3 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, 1121 Budapest, Konkoly Thege Miklós út 15-17, Hungary
4 MTA CSFK Lendület Near-Field Cosmology Research Group, Budapest, Hungary
5 Astronomy Department, Eötvös Loránd University, Pázmány P. s. 1/A, 1171 Budapest, Hungary
6 Institute of Physics, University of Szczecin, Wielkopolska 15, 70-453 Szczecin, Poland
7 The IEA, University of Reading, Philip Lyle Building, Whiteknights Campus, Reading, RG6 6BX, UK
8 Observatoire des Hauts Patys, 84410 Bédoin, France
9 Villefagnan Observatory, Villefagnan, France
10 Geneva Observatory, 1290 Sauverny, Switzerland
11 Les Engarouines Observatory, 84570 Mallemort-du-Comtat, France
12 Stazione Astronomica di Sozzago, 28060 Sozzago, Italy
13 Departamento de Sistema Solar, Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía s/n, 18008 Granada, Spain
14 Rose-Hulman Institute of Technology, CM 171 5500 Wabash Ave., Terre Haute, IN 47803, USA
15 Observatoire du Bois de Bardon, 16110 Taponnat, France
16 Elgin Observatory, 1155 Hartford St; Elgin, OR USA
17 Instituto de Astrofísica de Canarias, C/ Vía Lactea, s/n, 38205 La Laguna, Tenerife, Spain
18 Gran Telescopio Canarias (GRANTECAN), Cuesta de San José s/n, 38712 Breña Baja, La Palma, Spain
19 Lincaheira Observatory, Instituto Politécnico de Tomar, 2300-313 Tomar, Portugal
20 School of Physical Sciences, The Open University, MK7 6AA, UK
21 Chungbuk National University, 1, Chungdae-ro, Seowon-gu, Cheongju-si, Chungcheongbuk-do, Republic of Korea
22 Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong-gu, 305-348 Daejeon, Korea
23 Institute of Physics, Faculty of Natural Sciences, University of P. J. Šafárik, Park Angelinum 9, 040 01 Košice, Slovakia
24 Laboratory of Space Researches, Uzhhorod National University, Daleka st. 2a, 88000, Uzhhorod, Ukraine
25 Observatorio de Albox, Almeria, Spain
26 Observatório Nacional Rua General José Cristino, 77, 20921-400 Bairro Imperial de São Cristóvão Rio de Janeiro, RJ, Brasil
27 Mt. Suhora Observatory, Pedagogical University, Podchorążych 2, 30-084 Cracow, Poland
28 Organ Mesa Observatory, 4438 Organ Mesa Loop, Las Cruces, New Mexico 88011, USA
29 Command Module Observatory, 121 W. Alameda Dr., Tempe, AZ 85282, USA
30 Observatoire de Blauvac, 293 chemin de St Guillaume, 84570 St-Estève, France
31 Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA
32 Department of Physics, University of Adiyaman, 02040 Adiyaman, Turkey
33 Bisei Spaceguard Center, Japan Spaceguard Association, 1716-3, Okura, Bisei, Ibara, Okayama 714-1411, Japan
34 Kepler Institute of Astronomy, University of Zielona Góra, Lubuska 2, 65-265 Zielona Góra, Poland
Accepted: 9 April 2019
Context. Earlier work suggests that slowly rotating asteroids should have higher thermal inertias than faster rotators because the heat wave penetrates deeper into the subsurface. However, thermal inertias have been determined mainly for fast rotators due to selection effects in the available photometry used to obtain shape models required for thermophysical modelling (TPM).
Aims. Our aims are to mitigate these selection effects by producing shape models of slow rotators, to scale them and compute their thermal inertia with TPM, and to verify whether thermal inertia increases with the rotation period.
Methods. To decrease the bias against slow rotators, we conducted a photometric observing campaign of main-belt asteroids with periods longer than 12 h, from multiple stations worldwide, adding in some cases data from WISE and Kepler space telescopes. For spin and shape reconstruction we used the lightcurve inversion method, and to derive thermal inertias we applied a thermophysical model to fit available infrared data from IRAS, AKARI, and WISE.
Results. We present new models of 11 slow rotators that provide a good fit to the thermal data. In two cases, the TPM analysis showed a clear preference for one of the two possible mirror solutions. We derived the diameters and albedos of our targets in addition to their thermal inertias, which ranged between 3−3+33 and 45−30+60 J m−2 s−1∕2 K−1.
Conclusions. Together with our previous work, we have analysed 16 slow rotators from our dense survey with sizes between 30 and 150 km. The current sample thermal inertias vary widely, which does not confirm the earlier suggestion that slower rotators have higher thermal inertias.
Key words: minor planets, asteroids: general / techniques: photometric / radiation mechanisms: thermal
Full Table A.1 and photometric data from all individual nights are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (18.104.22.168) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/625/A139
© ESO 2019
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