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  • 1.
    Alho, Markku
    et al.
    School of Electrical Engineering, Aalto University, Maarinkatu 8, PO Box 15500, FI-00760 Aalto, Finland; Department of Physics, University of Helsinki, PO Box 68, FI-00014 Helsingin Yliopisto, Helsinki, Finland.
    Jarvinen, Riku
    School of Electrical Engineering, Aalto University, Maarinkatu 8, PO Box 15500, FI-00760 Aalto, Finland; Finnish Meteorological Institute, PO BOX 503, FI-00101 Helsinki, Finland.
    Wedlund, Cyril Simon
    Space Research Institute, Austrian Academy of Sciences, Schmiedlstraße 6, AT-8042 Graz, Austria.
    Nilsson, Hans
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, PO Box 812, SE-981 28 Kiruna, Sweden.
    Kallio, Esa
    School of Electrical Engineering, Aalto University, Maarinkatu 8, PO Box 15500, FI-00760 Aalto, Finland.
    Pulkkinen, Tuija I.
    School of Electrical Engineering, Aalto University, Maarinkatu 8, PO Box 15500, FI-00760 Aalto, Finland; Department of Climate and Space Sciences and Engineering, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143, US.
    Remote sensing of cometary bow shocks: modelled asymmetric outgassing and pickup ion observations2021In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 506, no 4, p. 4735-4749Article in journal (Refereed)
    Abstract [en]

    Despite the long escort by the ESA Rosetta mission, direct observations of a fully developed bow shock around 67P/Churyumov-Gerasimenko have not been reported. Expanding on our previous work on indirect observations of a shock, we model the large-scale features in cometary pickup ions, and compare the results with the ESA Rosetta Plasma Consortium Ion Composition Analyser ion spectrometer measurements over the pre-perihelion portion of the escort phase. Using our hybrid plasma simulation, an empirical, asymmetric outgassing model for 67P, and varied interplanetary magnetic field (IMF) clock angles, we model the evolution of the large-scale plasma environment. We find that the subsolar bow shock standoff distance is enhanced by asymmetric outgassing with a factor of 2 to 3, reaching up to 18 000 km approaching perihelion. We find that distinct spectral features in simulated pickup ion distributions are present for simulations with shock-like structures, with the details of the spectral features depending on shock standoff distance, heliocentric distance, and IMF configuration. Asymmetric outgassing along with IMF clock angle is found to have a strong effect on the location of the spectral features, while the IMF clock angle causes no significant effect on the bow shock standoff distance. These dependences further complicate the interpretation of the ion observations made by Rosetta. Our data-model comparison shows that the large-scale cometary plasma environment can be probed by remote sensing the pickup ions, at least when the comet’s activity is comparable to that of 67P, and the solar wind parameters are known.

  • 2.
    Antipov, Sergey V.
    et al.
    Department of Chemistry and Molecular Biology, University of Gothenburg.
    Gustafsson, Magnus
    Department of Chemistry and Molecular Biology, University of Gothenburg.
    Nyman, Gunnar
    Department of Chemistry and Molecular Biology, University of Gothenburg.
    Isotope effect in the formation of carbon monoxide by radiative association2013In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 430, no 2, p. 946-950Article in journal (Refereed)
    Abstract [en]

    Rate coefficients for the formation of 12CO and 13CO isotopologues of carbon monoxide by radiative association for T = 10–20 000 K are calculated using a quantum mechanical approach. It is shown that the presence of the potential barrier on the A1Π electronic state of CO leads to different formation channels for the isotopologues at low temperatures. The corresponding rate coefficients are fitted to an analytic formula.

  • 3.
    Behar, Etienne
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, Kiruna.
    Nilsson, Hans
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, Kiruna.
    Alho, M.
    Aalto University, School of Electrical Engineering, Department of Electronics and Nanoengineering, Finland.
    Goetz, C.
    Technische Universität Braunschweig, Institute for Geophysics and Extraterrestrial Physics, Germany.
    Tsurutani, B.
    Jet Propulsion Laboratory, California Institute of Technology, USA.
    The birth and growth of a solar wind cavity around a comet: Rosetta observations2017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 469, no Suppl. 2, p. S369-S403Article in journal (Refereed)
    Abstract [en]

    The Rosetta mission provided detailed observations of the growth of a cavity in the solar wind around comet 67P/Churyumov–Gerasimenko. As the comet approached the Sun, the plasma of cometary origin grew enough in density and size to present an obstacle to the solar wind. Our results demonstrate how the initial slight perturbations of the solar wind prefigure the formation of a solar wind cavity, with a particular interest placed on the discontinuity (solar wind cavity boundary) passing over the spacecraft. The slowing down and heating of the solar wind can be followed and understood in terms of single particle motion. We propose a simple geometric illustration that accounts for the observations, and shows how a cometary magnetosphere is seeded from the gradual steepening of an initially slight solar wind perturbation. A perspective is given concerning the difference between the diamagnetic cavity and the solar wind cavity.

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  • 4.
    Behar, Etienne
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, Kiruna.
    Tabone, B.
    LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Université, UPMC Univ. Paris.
    Nilsson, Hans
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, Kiruna.
    Dawn-dusk asymmetry induced by the Parker spiral angle in the plasma dynamics around comet 67P/Churyumov-Gerasimenko2018In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 478, no 2, p. 1570-1575Article in journal (Refereed)
    Abstract [en]

    When interacting, the solar wind and the ionised atmosphere of a comet exchange energy and momentum. Our aim is to understand the influence of the average Parker spiral configuration of the solar wind magnetic field on this interaction. We compare the theoretical expectations of an analytical generalised gyromotion with Rosetta observations at comet 67P/Churyumov-Gerasimenko. A statistical approach allows one to overcome the lack of upstream solar wind measurement. We find that additionally to their acceleration along (for cometary pick-up ions) or against (for solar wind ions) the upstream electric field orientation and sense, the cometary pick-up ions are drifting towards the dawn side of the coma, while the solar wind ions are drifting towards the dusk side of the coma, independent of the heliocentric distance. The dynamics of the interaction is not taking place in a plane, as often assumed in previous works.

  • 5.
    Franz, Jan
    et al.
    University of Gothenburg.
    Gustafsson, Magnus
    Department of Chemistry, University of Gothenburg.
    Nyman, Gunnar
    Department of Chemistry and Molecular Biology, University of Gothenburg.
    Formation of carbon-monoxide by radiative association: a quantum-dynamical study2011In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 414, no 4, p. 3547-3550Article in journal (Refereed)
    Abstract [en]

    Rate coefficients for the formation of carbon monoxide (CO) by radiative association of carbon and oxygen atoms are computed using quantum dynamical simulations. At temperatures above 10 K CO radiative association is dominated by C(3P) and O(3P) approaching on the A1Π potential energy curve. The rate coefficient is estimated as k=A(T/300 K)αexp−β/T with A= 1.39 × 10−18 cm3 s−1, α=−0.016 and β= 92.2 for temperatures between 6 and 127.2 K, and A= 1.36 × 10−17 cm3 s−1, α= 0.41 and β= 340 for temperatures between 127.2 and 15 000 K. Furthermore we computed the rate coefficients for approaching on the X1Σ+ curve. For temperatures below 200 K it is between 0.7 × 10−22 and 4 × 10−22 cm3 s−1.

  • 6.
    Grinin, V. P.
    et al.
    Pulkovo Astronomical Observatory, Russian Academy of Sciences, Pulkovskoye Shosse 65, St. Petersburg 196140, Russia; St. Petersburg State University, Universitetsky pr. 28, St. Petersburg 198504, Russia.
    Tambovtseva, L. V.
    Pulkovo Astronomical Observatory, Russian Academy of Sciences, Pulkovskoye Shosse 65, St. Petersburg 196140, Russia.
    Djupvik, A. A.
    Nordic Optical Telescope, Rambla José Ana Fernández Pérez 7, E-38711 Breña Baja, Spain; Department of Physics and Astronomy, Aarhus University, Munkegade 120, DK-8000 Aarhus C, Denmark.
    Gahm, G.
    Stockholm Observatory, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden.
    Grenman, Tiia
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Weber, H.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Bengtsson, H.
    SAAF, Svensk AmatörAstronomisk Förening, Sweden.
    De Angelis, H.
    SAAF, Svensk AmatörAstronomisk Förening, Sweden.
    Duszanowicz, G.
    SAAF, Svensk AmatörAstronomisk Förening, Sweden.
    Heinonen, D.
    SAAF, Svensk AmatörAstronomisk Förening, Sweden.
    Holmberg, G.
    SAAF, Svensk AmatörAstronomisk Förening, Sweden.
    Karlsson, T.
    SAAF, Svensk AmatörAstronomisk Förening, Sweden.
    Larsson, M.
    SAAF, Svensk AmatörAstronomisk Förening, Sweden.
    Warell, J.
    SAAF, Svensk AmatörAstronomisk Förening, Sweden.
    Wikander, T.
    SAAF, Svensk AmatörAstronomisk Förening, Sweden.
    Modelling UX Ori star eclipses based on spectral observations with the Nordic Optical Telescope - I. RR Tau2023In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 524, no 3, p. 4047-4061Article in journal (Refereed)
  • 7.
    Gustafsson, Magnus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Nyman, Gunnar
    Department of Chemistry and Molecular Biology, University of Gothenburg.
    Radiative association rate constant for the formation of CO: the importance of the first excited 1Σ+ state2015In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 448, no 3, p. 2562-2565Article in journal (Refereed)
    Abstract [en]

    The thermal rate constant for production of carbon monoxide, in its electronic ground state, through radiative association of carbon (C) and oxygen (O) atoms is computed. A combination of quantum and classical dynamics methods are employed. In particular, we investigate the importance of the mechanism where C and O approach each other on the 21Σ+ potential energy curve. Accounting for this reaction turns out to add about 75 per cent to the rate constant at 10000 K. We expect the results to be important for studies of the chemistry in interstellar gas, particularly in metal-rich ejecta of supernovae. Since a significant isotope effect has been predicted previously both stable carbon isotopes 12C and 13C are considered in the present study.

  • 8.
    Hanimeli, Ekim Taylan
    et al.
    Luleå University of Technology. Université de Toulouse, UPS-OMP, IRAP, CNRS, 14 Avenue Edouard Belin, F-31400 Toulouse, France.
    Tutusaus, Isaac
    Université de Toulouse, UPS-OMP, IRAP, CNRS, 14 Avenue Edouard Belin, F-31400 Toulouse, France; Institute of Space Sciences (ICE, CSIC), Campus UAB, Carrer de Can Magrans, s/n, E-08193 Barcelona, Spain; Institut d’Estudis Espacials de Catalunya (IEEC), Carrer Gran Capità 2-4, E-08193 Barcelona, Spain.
    Lamine, Brahim
    Université de Toulouse, UPS-OMP, IRAP, CNRS, 14 Avenue Edouard Belin, F-31400 Toulouse, France.
    Blanchard, Alain
    Université de Toulouse, UPS-OMP, IRAP, CNRS, 14 Avenue Edouard Belin, F-31400 Toulouse, France.
    Low-redshift tests of Newtonian cosmologies with a time-varying gravitational constant2020In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 497, no 4, p. 4407-4415Article in journal (Refereed)
    Abstract [en]

    In this work, we investigate Newtonian cosmologies with a time-varying gravitational constant, G(t). We examine whether such models can reproduce the low-redshift cosmological observations without a cosmological constant, or any other sort of explicit dark energy fluid. Starting with a modified Newton’s second law, where G is taken as a function of time, we derive the first Friedmann-Lemaitre equation, where a second parameter, G*, appears as the gravitational constant. This parameter is related to the original G from the second law, which remains in the acceleration equation. We use this approach to reproduce various cosmological scenarios that are studied in the literature, and we test these models with low-redshift probes: type-Ia supernovae (SNIa), baryon acoustic oscillations, and cosmic chronometers, taking also into account a possible change in the supernovae intrinsic luminosity with redshift. As a result, we obtain several models with similar chi(2) values as the standard Delta CDM cosmology. When we allow for a redshift-dependence of the SNIa intrinsic luminosity, a model with a G exponentially decreasing to zero while remaining positive (model 4) can explain the observations without acceleration. When we assume no redshift-dependence of SNIa, the observations favour a negative G at large scales, while G* remains positive for most of these models. We conclude that these models offer interesting interpretations to the low-redshift cosmological observations, without needing a dark energy term.

  • 9.
    Ishiguro, Masateru
    et al.
    Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; SNU Astronomy Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
    Bach, Yoonsoo P.
    Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; SNU Astronomy Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
    Geem, Jooyeon
    Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; SNU Astronomy Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
    Naito, Hiroyuki
    Nayoro Observatory, 157-1 Nisshin, Nayoro, Hokkaido 096-0066, Japan.
    Kuroda, Daisuke
    Okayama Observatory, Kyoto University, 3037-5 Honjo, Kamogata, Asakuchi, Okayama 719-0232, Japan.
    Im, Myungshin
    Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; SNU Astronomy Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
    Lee, Myung Gyoon
    Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; SNU Astronomy Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
    Seo, Jinguk
    Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; SNU Astronomy Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
    Jin, Sunho
    Department of Physics and Astronomy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; SNU Astronomy Research Center, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea.
    Kwon, Yuna G.
    Institut für Geophysik und Extraterrestrische Physik, Technische Universität Braunschweig, Mendelssohnstr. 3, 38106 Braunschweig, Germany.
    Oono, Tatsuharu
    Department of Cosmosciences, Graduate School of Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
    Takagi, Seiko
    Department of Cosmosciences, Graduate School of Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
    Sato, Mitsuteru
    Department of Cosmosciences, Graduate School of Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
    Kuramoto, Kiyoshi
    Department of Cosmosciences, Graduate School of Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
    Ito, Takashi
    National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Planetary Exploration Research Center, Chiba Institute of Technology, Tsudanuma, Narashino, Chiba 275-0016, Japan.
    Hasegawa, Sunao
    Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210, Japan.
    Yoshida, Fumi
    University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahata, Kitakyusyu 807-8555, Japan; Planetary Exploration Research Center, Chiba Institute of Technology, Tsudanuma, Narashino, Chiba 275-0016, Japan.
    Arai, Tomoko
    Planetary Exploration Research Center, Chiba Institute of Technology, Tsudanuma, Narashino, Chiba 275-0016, Japan.
    Akitaya, Hiroshi
    Planetary Exploration Research Center, Chiba Institute of Technology, Tsudanuma, Narashino, Chiba 275-0016, Japan.
    Sekiguchi, Tomohiko
    Asahikawa Campus, Hokkaido University of Education, Hokumon, Asahikawa, Hokkaido 070-8621, Japan.
    Okazaki, Ryo
    Asahikawa Campus, Hokkaido University of Education, Hokumon, Asahikawa, Hokkaido 070-8621, Japan.
    Imai, Masataka
    Faculty of Science, Kyoto Sangyo University, Banyukan B401, Motoyama, Kamigamo, Kita-Ku, Kyoto-shi, Kyoto 603-8555, Japan.
    Ohtsuka, Katsuhito
    Tokyo Meteor Network, Daisawa 1-27-5, Setagaya, Tokyo 155-0032, Japan.
    Watanabe, Makoto
    Department of Applied Physics, Okayama University of Science, 1-1 Ridaicho, Kita-ku, Okayama, Okayama 700-0005, Japan.
    Takahashi, Jun
    Centerfor Astronomy, University of Hyogo, 407-2 Nishigaichi, Sayo, Hyogo 679-5313, Japan.
    Devogèle, Maxime
    Arecibo Observatory, University of Central Florida, HC-3 Box 53995, Arecibo, PR 00612, USA.
    Fedorets, Grigori
    Department of Physics, University of Helsinki, PO Box 64, FI-00014 University of Helsinki, Finland; Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast BT7 1NN, UK.
    Siltala, Lauri
    Department of Physics, University of Helsinki, PO Box 64, FI-00014 University of Helsinki, Finland; Nordic Optical Telescope, Apartado 474, E-38700 S/C de La Palma, Santa Cruz de Tenerife, Spain.
    Granvik, Mikael
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Department of Physics, University of Helsinki, PO Box 64, FI-00014 University of Helsinki, Finland.
    Polarimetric properties of the near-Sun asteroid (155140) 2005 UD in comparison with other asteroids and meteoritic samples2022In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 509, no 3, p. 4128-4142Article in journal (Refereed)
    Abstract [en]

    The investigation of asteroids near the Sun is important for understanding the final evolutionary stage of primitive Solar system objects. A near-Sun asteroid (NSA), (155140) 2005 UD, has orbital elements similar to those of (3200) Phaethon (the target asteroid for the JAXA’s DESTINY+ mission). We conducted photometric and polarimetric observations of 2005 UD and found that this asteroid exhibits a polarization phase curve similar to that of Phaethon over a wide range of observed solar phase angles (α = 20–105°) but different from those of (101955) Bennu and (162173) Ryugu (asteroids composed of hydrated carbonaceous materials). At a low phase angle (α ≲ 30°), the polarimetric properties of these NSAs (2005 UD and Phaethon) are consistent with anhydrous carbonaceous chondrites, while the properties of Bennu are consistent with hydrous carbonaceous chondrites. We derived the geometric albedo, pV ∼ 0.1 (in the range of 0.088–0.109); mean V-band absolute magnitude, HV = 17.54 ± 0.02; synodic rotational period, Trot=5.2388±0.0022h (the two-peaked solution is assumed); and effective mean diameter, Deff=1.32±0.06km⁠. At large phase angles (α ≳ 80°), the polarization phase curve are likely explained by the dominance of large grains and the paucity of small micron-sized grains. We conclude that the polarimetric similarity of these NSAs can be attributed to the intense solar heating of carbonaceous materials around their perihelia, where large anhydrous particles with small porosity could be produced by sintering.

  • 10.
    Jones (nee Burdakova), Daria
    et al.
    Department of Chemistry and Molecular Biology, University of Gothenburg , SE-405 30 Gothenburg, Sweden.
    Gustafsson, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Nyman, Gunnar
    Department of Chemistry and Molecular Biology, University of Gothenburg , SE-405 30 Gothenburg, Sweden.
    Formation of the CH/CD molecules through radiative association of C with H/D2022In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 517, no 4, p. 4892-4901Article in journal (Refereed)
    Abstract [en]

    Reaction rate constants have been calculated for the formation of CH and CD molecules through radiative association of C and H/D atoms in their ground states. Quantum mechanical and semiclassical/classical methods were used to obtain the reaction cross-sections. Shape resonances and inverse pre-dissociation are accounted for with Breit–Wigner theory. The potential, permanent/transition dipole moment curves and experimental pre-dissociation widths are taken from the literature. The resulting reaction rate constants were fitted to the Kooij formula for use in astrochemical modelling. Our rate constant is 3.5 × 10−17 cm3 s−1 at 100 K and it peaks at 20 K, where it is 8.0 × 10−17 cm3 s−1. These values are larger than what has been obtained in earlier studies but not large enough to account for the interstellar abundance of CH.

  • 11.
    Kathir, R. K.
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Department of Chemistry and Molecular Biology, University of Gothenburg, SE-41296 Gothenburg, Sweden.
    Nyman, Gunnar
    Department of Chemistry and Molecular Biology, University of Gothenburg, SE-41296 Gothenburg, Sweden.
    Gustafsson, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    The rate constant for formation of HCl through radiative association2017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 470, no 3, p. 3068-3070Article in journal (Refereed)
    Abstract [en]

    Formation of HCl in its electronic ground state through radiative association is studied. We ignore spin-orbit couplings and then the formation can happen through two dipole-allowed reactions, one involving an electronic transition and one where the H and Cl atoms approach and remain in the ground electronic molecular state. The radiative association rate constant is computed, through a combination of classical and quantum methods, for use in modelling of interstellar chemistry.

  • 12.
    Lethuillier, A.
    et al.
    Institut für Geophysik und extraterrestrische Physik (IGeP), TU Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany.
    Feller, C.
    Physikalisches Institut, Universität Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
    Kaufmann, Erika
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Space Research Institute, Austrian Academy of Science, Schmiedlstraße 6, A-8042 Graz, Austria.
    Becerra, P.
    Physikalisches Institut, Universität Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
    Hänni, N.
    Physikalisches Institut, Universität Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
    Diethelm, R.
    Institut für Geophysik und extraterrestrische Physik (IGeP), TU Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany.
    Kreuzig, C.
    Institut für Geophysik und extraterrestrische Physik (IGeP), TU Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany.
    Gundlach, B.
    Institut für Geophysik und extraterrestrische Physik (IGeP), TU Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany.
    Blum, J.
    Institut für Geophysik und extraterrestrische Physik (IGeP), TU Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany.
    Pommerol, A.
    Physikalisches Institut, Universität Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
    Kargl, G.
    Space Research Institute, Austrian Academy of Science, Schmiedlstraße 6, A-8042 Graz, Austria.
    Laddha, S.
    Space Research Institute, Austrian Academy of Science, Schmiedlstraße 6, A-8042 Graz, Austria.
    Denisova, K.
    Institut für Physik der Kondensierten Materie (IPKM), TU Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany.
    Kührt, E.
    Deutsches Zentrum für Luft- und Raumfahrt, Rutherfordstraße 2, D-12489 Berlin-Adlershof, Germany.
    Capelo, H. L.
    Physikalisches Institut, Universität Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
    Haack, D.
    Deutsches Zentrum für Luft- und Raumfahrt, Rutherfordstraße 2, D-12489 Berlin-Adlershof, Germany.
    Zhang, X.
    Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology, Beijing 100094, China.
    Knollenberg, J.
    Deutsches Zentrum für Luft- und Raumfahrt, Rutherfordstraße 2, D-12489 Berlin-Adlershof, Germany.
    Molinski, N. S.
    Institut für Geophysik und extraterrestrische Physik (IGeP), TU Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany.
    Gilke, T.
    Institut für Geophysik und extraterrestrische Physik (IGeP), TU Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany.
    Sierks, H.
    Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Gottingen, ¨ Germany.
    Tiefenbacher, P.
    Space Research Institute, Austrian Academy of Science, Schmiedlstraße 6, A-8042 Graz, Austria.
    Güttler, C.
    Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Gottingen, ¨ Germany.
    Otto, K. A.
    Deutsches Zentrum für Luft- und Raumfahrt, Rutherfordstraße 2, D-12489 Berlin-Adlershof, Germany.
    Bischoff, D.
    Institut für Geophysik und extraterrestrische Physik (IGeP), TU Braunschweig, Mendelssohnstr. 3, D-38106 Braunschweig, Germany.
    Schweighart, M.
    Space Research Institute, Austrian Academy of Science, Schmiedlstraße 6, A-8042 Graz, Austria.
    Hagermann, Axel
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Jäggi, N.
    Physikalisches Institut, Universität Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland.
    Cometary dust analogues for physics experiments2022In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 515, no 3, p. 3420-3438Article in journal (Refereed)
    Abstract [en]

    The CoPhyLab (Cometary Physics Laboratory) project is designed to study the physics of comets through a series of earth-based experiments. For these experiments, a dust analogue was created with physical properties comparable to those of the non-volatile dust found on comets. This ‘CoPhyLab dust’ is planned to be mixed with water and CO2 ice and placed under cometary conditions in vacuum chambers to study the physical processes taking place on the nuclei of comets. In order to develop this dust analogue, we mixed two components representative for the non-volatile materials present in cometary nuclei. We chose silica dust as a representative for the mineral phase and charcoal for the organic phase, which also acts as a darkening agent. In this paper, we provide an overview of known cometary analogues before presenting measurements of eight physical properties of different mixtures of the two materials and a comparison of these measurements with known cometary values. The physical properties of interest are particle size, density, gas permeability, spectrophotometry, and mechanical, thermal, and electrical properties. We found that the analogue dust that matches the highest number of physical properties of cometary materials consists of a mixture of either 60 per cent/40 per cent or 70 per cent/30 per cent of silica dust/charcoal by mass. These best-fit dust analogue will be used in future CoPhyLab experiments.

  • 13.
    Nicolaou, G.
    et al.
    Swedish Institute of Space Physics, SE-981 28 Kiruna, Sweden.
    Behar, Etienne
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, SE-981 28 Kiruna, Sweden.
    Nilsson, Hans
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, SE-981 28 Kiruna, Sweden.
    Wieser, M.
    Swedish Institute of Space Physics, SE-981 28 Kiruna, Sweden.
    Yamauchi, M.
    Swedish Institute of Space Physics, SE-981 28 Kiruna, Sweden.
    Berčič, Laura
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, SE-981 28 Kiruna, Sweden.
    Stenberg Wieser, G.
    Swedish Institute of Space Physics, SE-981 28 Kiruna, Sweden.
    Energy-angle dispersion of accelerated heavy ions at 67P/Churyumov-Gerasimenko: Implication in the mass-loading mechanism2017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 469, p. S339-S345Article in journal (Refereed)
    Abstract [en]

    The Rosetta spacecraft studied the comet 67P/Churyumov-Gerasimenko for nearly two years. The Ion Composition Analyzer instrument on board Rosetta observed the positive ion distributions in the environment of the comet during the mission. A portion of the comet's neutral coma is expected to get ionized, depending on the comet's activity and position relative to the Sun, and the newly created ions are picked up and accelerated by the solar wind electric field, while the solar wind flow is deflected in the opposite direction. This interaction, known as the mass-loading mechanism, was previously studied by comparing the bulk flow direction of both the solar wind protons and the accelerated cometary ions with respect to the direction of the magnetic and the convective solar wind electric field. In this study, we show that energy-angle dispersion is occasionally observed. We report two types of dispersion: one where the observed motion is consistent with ions gyrating in the local magnetic field and another where the energy-angle dispersion is opposite to that expected from gyration in the local magnetic field. Given that the cometary ion gyro-radius in the undisturbed solar wind magnetic and electric field is expected to be too large to be detected in this way, our observations indicate that the local electric field might be significantly smaller than that of the undisturbed solar wind. We also discuss how the energy-angle dispersion, which is not consistent with gyration, may occur due to spatially inhomogeneous densities and electric fields.

  • 14.
    Nilsson, Hans
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, Box 812, SE-981 28 Kiruna, Sweden.
    Stenberg Wieser, Gabriella
    Swedish Institute of Space Physics, Box 812, SE-981 28 Kiruna, Sweden.
    Behar, Etienne
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Swedish Institute of Space Physics, Box 812, SE-981 28 Kiruna, Sweden.
    Gunell, Herbert
    Royal Belgian Institute for Space Aeronomy, Avenue Circulaire 3, B-1180 Brussels, Belgium; Department of Physics, Umeå University, SE-901 87 Umeå, Sweden.
    Wieser, Martin
    Swedish Institute of Space Physics, Box 812, SE-981 28 Kiruna, Sweden.
    Galand, Marina
    Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK.
    Simon Wedlund, Cyril
    Department of Physics, University of Oslo, PO Box 1048 Blindern, N-0316 Oslo, Norway.
    Alho, Markku
    Department of Electronics and Nanoengineering, School of Electrical Engineering, Aalto University, PO Box 15500, FI-00076 Aalto, Finland.
    Goetz, Charlotte
    Institut für Geophysik und extraterrestrische Physik, Technische Universität Braunschweig, Mendelssohnstr 3, D-38106 Braunschweig, Germany.
    Yamauchi, Masatoshi
    Swedish Institute of Space Physics, Box 812, SE-981 28 Kiruna, Sweden.
    Henri, Pierre
    LPC2E-CNRS, 3A avenue de la Recherche Scientifique, F-45071 Orléans, Cedex, 2, Orléans, France.
    Odelstad, Elias
    Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala, Sweden.
    Vigren, Erik
    Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala, Sweden.
    Evolution of the ion environment of comet 67P during the Rosetta mission as seen by RPC-ICA2017In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 469, no Suppl_2, p. S252-S261Article in journal (Refereed)
    Abstract [en]

    Rosetta has followed comet 67P from low activity at more than 3.6 au heliocentric distance to high activity at perihelion (1.24 au) and then out again. We provide a general overview of the evolution of the dynamic ion environment using data from the RPC-ICA ion spectrometer. We discuss where Rosetta was located within the evolving comet magnetosphere. For the initial observations, the solar wind permeated all of the coma. In 2015 mid-April, the solar wind started to disappear from the observation region, to re-appear again in 2015 December. Low-energy cometary ions were seen at first when Rosetta was about 100 km from the nucleus at 3.6 au, and soon after consistently throughout the mission except during the excursions to farther distances from the comet. The observed flux of low-energy ions was relatively constant due to Rosetta's orbit changing with comet activity. Accelerated cometary ions, moving mainly in the antisunward direction gradually became more common as comet activity increased. These accelerated cometary ions kept being observed also after the solar wind disappeared from the location of Rosetta, with somewhat higher fluxes further away from the nucleus. Around perihelion, when Rosetta was relatively deep within the comet magnetosphere, the fluxes of accelerated cometary ions decreased, as did their maximum energy. The disappearance of more energetic cometary ions at close distance during high activity is suggested to be due to a flow pattern where these ions flow around the obstacle of the denser coma or due to charge exchange losses.

  • 15.
    Pietranera, Luca
    et al.
    School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom; School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom.
    Buehler, Stefan
    Institut fr Umweltphysik, Universität Bremen, Bremen, Germany.
    Calisse, Paolo G.
    School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom.
    Emde, Claudia
    Deutsches Zentrum fuer Luft- und Raumfahrt (DLR), Institut fuer Physik der Atmosphaere, Oberpfaffenhofen, Germany.
    Hayton, Darren
    School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom.
    John, Viju Oommen
    Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, United States.
    Maffei, Bruno
    School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom.
    Piccirillo, Lucio
    School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom.
    Pisano, Giampaolo
    School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom.
    Savini, Giorgio
    School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom.
    Sreerekha, T. R.
    Met Office, Exeter, United Kingdom.
    Observing cosmic microwave background polarisation through ice2007In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 376, no 2, p. 645-650Article in journal (Refereed)
    Abstract [en]

    Ice crystal clouds in the upper troposphere can generate polarization signals at the μK level. This signal can seriously affect very sensitive ground-based searches for E and B modes of cosmic microwave background polarization. In this paper, we estimate this effect within the CℓOVER experiment observing bands (97, 150 and 220 GHz) for the selected observing site (Llano de Chajnantor, Atacama desert, Chile). The results show that the polarization signal from the clouds can be of the order of or even bigger than the cosmic microwave background expected polarization. Climatological data suggest that this signal is fairly constant over the whole year in Antarctica. On the other hand, the stronger seasonal variability in Atacama allows for a 50 per cent of clean observations during the dry season.

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  • 16.
    Szabo, Peter
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Gustafsson, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Formation of the NH molecule and its isotopologues through radiative association2019In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 483, no 3, p. 3574-3578Article in journal (Refereed)
    Abstract [en]

    The rate coefficients and the cross-sections for the formation of imidogen (NH) molecule (and its isotopologues: 15NH and ND) through radiative association are determined by employing quantum mechanical perturbation theory, classical Larmor formula, and Breit–Wigner theory. We suggest the radiative association process as possible route for NH production in diffuse interstellar clouds.

  • 17.
    Toliou, Athanasia
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Granvik, Mikael
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Department of Physics, University of Helsinki, PO Box 64, Helsinki, FI-00014, Finland.
    Resonant mechanisms that produce near-Sun asteroids2023In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 521, no 4, p. 4819-4837Article in journal (Refereed)
  • 18.
    Toliou, Athanasia
    et al.
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Granvik, Mikael
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Department of Physics, University of Helsinki, PO Box 64, FI-00014 Helsinki, Finland.
    Tsirvoulis, Georgios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Minimum perihelion distances and associated dwell times for near-Earth asteroids2021In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 506, no 3, p. 3301-3312Article in journal (Refereed)
    Abstract [en]

    The observed near-Earth asteroid (NEA) population contains very few objects with small perihelion distances, say, q≲0.2au⁠. NEAs that currently have orbits with larger q might be hiding a past evolution during which they have approached closer to the Sun. We present a probabilistic assessment of the minimum q that an asteroid has reached during its orbital history. At the same time, we offer an estimate of the dwell time, that is, the time q has been in a specific range. We have re-analysed orbital integrations of test asteroids from the moment they enter the near-Earth region until they either collide with a major body or are thrown out from the inner Solar system. We considered a total disruption of asteroids at certain q as a function of absolute magnitude (H). We calculated the probability that an asteroid with given orbital elements and H has reached a q smaller than a given threshold value and its respective dwell time in that range. We have constructed a look-up table that can be used to study the past orbital and thermal evolution of asteroids as well as meteorite falls and their possible parent bodies. An application to 25 meteorite falls shows that carbonaceous chondrites typically have short dwell times at small q, whereas for ordinary chondrites it ranges from 10000 to 500000 yr. A dearth of meteorite falls with long dwell times and small minimum q supports a supercatastrophic disruption of asteroids at small q.

  • 19.
    Zámečníková, Martina
    et al.
    Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic.
    Gustafsson, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Nyman, Gunnar
    Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden.
    Soldán, Pavel
    Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic.
    Formation of CO+ by radiative association II2020In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 492, no 3, p. 3794-3802Article in journal (Refereed)
    Abstract [en]

    Radiative association of an oxygen atom with a carbon cation is investigated using quantal and semiclassical methods. The total rate coefficient for spontaneous radiative association of O(2s22p4, 3P) with C+(2s22p, 2P) on the doublet manifold is determined from the corresponding cross-sections. The cross-sections for the 12 Σ - → A2 II, 22 Σ - → A2II, and C2 Δ → A2II continuum-bound processes are calculated either semiclassically, in combination with the Breit-Wigner approach, or fully quantum mechanically. In the temperature range 10-10 000 K, our recommended total rate coefficient, obtained from these calculations and the data of Zámecniková et al. (2019), slowly increases from 7.5 × 10-18 cm3s-1 to 2.1 × 10-17 cm3s-1. Corresponding aspects of the CO+ and CO formations in SN 1987A are discussed

  • 20.
    Zámečníková, Martina
    et al.
    Charles University.
    Soldán, Pavel
    Charles University.
    Gustafsson, Magnus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Nyman, Gunnar
    University of Gothenburg.
    Formation of CO+ by radiative association2019In: Monthly notices of the Royal Astronomical Society, ISSN 0035-8711, E-ISSN 1365-2966, Vol. 489, no 2, p. 2954-2960Article in journal (Refereed)
    Abstract [en]

    We theoretically estimate formation rate coefficients for CO+ through the radiative association of C+(2P) with O(3P). In 1989, Petuchowski et al. claimed radiative association to be the most important route for CO+ formation in SN 1987A. In 1990, Dalgarno, Du and You challenged this claim. Therefore, in this study, we improve previous estimates of the radiative association rate coefficients for forming CO+ from C+(2P) and O(3P). To do this, we perform quantum mechanically based perturbation theory calculations as well as semiclassical calculations, which are combined with Breit–Wigner theory in order to add the effect of shape resonances. We explicitly include four electronic transitions. The required potential energy and transition dipole-moment curves are obtained through large basis set multireference configuration interaction electronic structure calculations. We report cross-sections and from these we obtain rate coefficients in the range of 10 –10 000 K, finding that the CO+ formation rate coefficient is larger than the previous estimate by Dalgarno et al. Still our results support their claim that in SN 1987A, CO is mainly formed through radiative association and not through the charge transfer reaction CO+ + O → CO + Oas earlier suggested by Petuchowski et al.

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