Article
Astronomy & Astrophysics
Giovanni Poggiali, M. Matsuoka, M. A. Barucci, J. R. Brucato, P. Beck, S. Fornasier, A. Doressoundiram, F. Merlin, A. Alberini
Summary: This article reviews past spectroscopic observations of the Martian moons and presents new laboratory measurements. Preliminary results indicate that the surface of Phobos and Deimos may contain a significant amount of dark components or minerals produced by space weathering.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
X. Guo, J. G. Yan, X. Yang, L. Liu, Y. H. Chen, M. Ye, J. P. Barriot
Summary: Doppler radio tracking data from Tianwen-1, China's first Mars mission, can help estimate the gravity field of Phobos. By considering additional flybys of Phobos by Tianwen-1 and Mars Express spacecraft, a determination up to degree and order 3 is feasible, and possibly degree and order 5. The cases of homogeneous, core-dominated, and mantle-dominated Phobos are studied, with the mantle-dominated case being the easiest to detect, followed by homogeneous and core-dominated cases. Implications for modeling the internal structure of Phobos are also discussed.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Timothee Vaillant, Alexandre C. M. Correia
Summary: In this paper, we study the effects of secular resonances on the orbit of a satellite, particularly eviction resonances, which can significantly modify the eccentricity and inclination of the satellite. We estimate the impact of resonance crossing on the satellite's orbit, including capture probabilities, based on several parameters. Additionally, we use frequency map analysis to study resonant dynamics and find that some secular resonances may overlap, leading to chaotic motion for the satellite's inclination.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Benno A. Neuenschwander, Ravit Helled
Summary: This paper presents empirical structure models of Uranus and Neptune and predicts their rotation periods and wind depths by using higher order gravitational coefficients. The study finds that faster rotation and deep winds favor centrally concentrated density distributions. Accurate measurements of the gravity field and moment of inertia can constrain their internal structures and wind depths.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Yutian Cao, Dandan Niu, Wenjun Liang, Jun Cui, Xiaoshu Wu, Xin Wan, Jiahao Zhong, Lei Li, Zhaojin Rong, Yong Wei
Summary: Thermal electron depression and energetic electron depletion are observed in the nightside Martian ionosphere. While energetic electron depletion has been extensively studied, there is limited research on thermal electron depression and the correlation between the two is unknown. Through Mars Express total electron content (TEC) measurements, a large number of TEC depression features are identified, with large amplitude depression being more frequently observed near strong magnetic fields and small amplitude depression uniformly distributed across the Martian surface.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Xu Huang, Hao Gu, Jun Cui, Xiaoshu Wu, Mingyang Sun
Summary: This study evaluates the effects of the 2018 global dust storm on the photochemical escape of atomic C, N, and O on Mars. It uses multi-instrument measurements and a one-dimensional Monte Carlo model to calculate the escape probability profile and derive the photochemical escape rates. The results show that the GDS-induced C, N, and O escape is generally reduced by about 30-40% compared to the pre-GDS state, contrary to the well-known result of GDS-induced strong enhancement of atomic H escape.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Antonin Wargnier, G. Poggiali, A. Doressoundiram, T. Gautier, P. Beck, A. Buch, N. Ruscassier, S. Fornasier, M. A. Barucci
Summary: The next sample return mission of JAXA, called MMX, aims to investigate the origin of the martian moons Phobos and Deimos. As part of the mission preparation, a new laboratory spectral simulant was developed to accurately reproduce the red and featureless spectrum of Phobos. This simulant showed a better match for the Phobos spectrum in the visible and near-infrared compared to previously proposed simulants.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Ludwig Scheibe, Nadine Nettelmann, Ronald Redmer
Summary: Thermal evolution models of Uranus and Neptune suggest that their luminosities are inconsistent with the classical assumption of an adiabatic interior, with the influence of a thermally conductive boundary layer being a significant factor. Even a thin conductive layer of a few kilometers can greatly affect planetary cooling, resulting in either brighter or fainter appearances compared to the adiabatic case. The models also indicate that Uranus may have been in equilibrium with solar flux for a longer period of time.
ASTRONOMY & ASTROPHYSICS
(2021)
Review
Astronomy & Astrophysics
Ravit Helled, David J. Stevenson, Jonathan Lunine, Scott J. Bolton, Nadine Nettelmann, Sushil Atreya, Tristan Guillot, Burkhard Militzer, Yamila Miguel, William B. Hubbard
Summary: The Juno mission has provided new insights into Jupiter's internal structure and challenged current models of its formation and evolution. This paper discusses potential models that can explain the composition gradients and complex structure observed by Juno, and the constraints they impose. The findings suggest that Jupiter's formation and evolution may differ from standard models, and could involve an extended formation phase or giant impacts.
Article
Astronomy & Astrophysics
Anna C. Childs, Cody Shakespeare, David R. Rice, Chao-Chin Yang, Jason H. Steffen
Summary: This study investigates the formation of the TRAPPIST-1 planetary system, exploring the composition and structure of the planets. The research shows that the inner two planets likely experienced giant impacts and are desiccated, while the outer planets have a primordial hydrosphere. Additionally, all planets are found to have a core in their interior structure.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
M. Kervazo, G. Tobie, G. Choblet, C. Dumoulin, M. Behounkova
Summary: This study investigates the role of melt presence on both shear and bulk dissipation in Io's mantle, finding that bulk dissipation can enhance tidal heating by up to a factor of ten above a critical melt fraction. It also shows that the thinner the partially molten layer, the greater the effect, and bulk dissipation significantly affects the spatial pattern of tidal dissipation in partially molten layers, potentially contributing from 50 to 90% of Io's global tidal heat power.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
B. Charnay, G. Tobie, S. Lebonnois, R. D. Lorenz
Summary: By studying Titan's atmosphere, the Dragonfly mission can provide valuable constraints on the interior of Titan.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Xing Wang, Xiaojun Xu, Jun Cui, Hao Gu, Dandan Niu, Zilu Zhou, Qing Chang, Qi Xu, Lei Luo, Peishan He, Siqi Yi
Summary: The MAVEN mission has observed oscillations in the densities, velocities, and temperatures of ionospheric plasma on Mars, which are likely caused by atmospheric gravity waves. A wave-electron interaction model has been proposed to investigate the electron density variations in different regions of the Martian ionosphere dominated by crustal magnetic fields and draped interplanetary magnetic fields. The model results show comparable patterns with satellite observations and reveal that electron density fluctuations range from 40% to 83% and 29% to 125% for the two regions, with wave-induced vertical electron flux peaks occurring at altitudes between 115 km and 179 km. The orientation of the Martian magnetic field has a significant influence on the electron motions associated with the propagating gravity waves.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Xing Wang, Xiaojun Xu, Jun Cui, Hao Gu, Dandan Niu, Zilu Zhou, Qing Chang, Qi Xu, Lei Luo, Peishan He, Siqi Yi
Summary: This study investigates electron density variations in the Martian ionosphere using a linear wave-electron interaction model, revealing that electron density fluctuations are associated with magnetic fields and significantly influenced by field orientations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Xi Guo, Jianguo Yan, Tom Andert, Xuan Yang, Martin Paetzold, Matthias Hahn, Mao Ye, Shanhong Liu, Fei Li, Jean-Pierre Barriot
Summary: The research indicates that Phobos may have a stratified internal structure with a core lighter than the mantle. However, the possibility of Phobos being homogeneous cannot be strictly ruled out.
ASTRONOMY & ASTROPHYSICS
(2021)