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
H. S. Wang, S. P. Quanz, D. Yong, F. Liu, F. Seidler, L. Acuna, S. J. Mojzsis
Summary: This study aims to understand the mineralogy and interior structure of terrestrial exoplanets by analyzing the chemical composition of planet-hosting stars. The results show that most of these exoplanets have Earth-like composition, except for two specific cases.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
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
J-M Hure
Summary: This article discusses the equilibrium conditions for a body made of two homogeneous components separated by oblate spheroidal surfaces and in relative motion. Exact solutions are not allowed for rigid rotation unless a specific ambient pressure is present, but approximations can be obtained for configurations involving a small confocal parameter. The problem has two families of solutions, depending on the pressure along the common interface. The analytical approach compares well with numerical solutions obtained from the self-consistent-field method and practical formulas are derived for slowly rotating star/planet interiors.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Wanying Kang, John Marshall, Tushar Mittal, Suyash Bire
Summary: This study explores the ocean dynamics and tracer/heat transport associated with geysers on the south pole of Enceladus, finding that the warming signal is diffused and insufficient to prevent the geysers from freezing over. However, if the heating is assumed to be local, the geysers can be sustained.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
S. Bloot, Y. Miguel, M. Bazot, S. Howard
Summary: In this study, a method based on a state-of-the-art interior code and a Bayesian framework is proposed to estimate the interior structure of exoplanets using various data including mass, radius, equilibrium temperature, and atmospheric metallicity. Although the current data does not allow determination of the internal structure model, information about the internal properties of the planets, such as core mass, can still be obtained through atmospheric measurements.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
B. Basillais, J-M Hure
Summary: In this study, the expressions for the gravitational moments J2n of a system consisting of homogeneous layers separated by spheroidal surfaces and in relative rotational motion are derived using the theory of nested figures. The inverse problem of finding the equilibrium configurations that exactly reproduce a set of observables is discussed. The method is applied to Jupiter, and the results show good agreement with numerical solutions obtained from the self-consistent field method.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Keavin Moore, Nicolas B. Cowan, Charles-Edouard Boukare
Summary: Earth-like planets orbiting M-dwarf stars are the best targets for finding signs of life. However, their habitability is threatened by water loss to space from high radiation flux. Research shows that a longer-lived surface magma ocean can help retain water, but it may also sequester significant water in the mantle, affecting surface habitability. Magma oceans and deep-water cycling can maintain or recover habitable surface conditions on these planets under certain conditions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Amy Bonsor, Paula Jofre, Oliver Shorttle, Laura K. Rogers, Siyi Xu, Melis Carl
Summary: This work investigates whether planets and stars maintain consistency in refractory composition, and explores if this phenomenon applies in exoplanetary systems. By analyzing binary companions, it is found that the elemental abundances of stars and planetary material accreted by white dwarfs are consistent with the hypothesis of planets and host-stars having the same true abundances.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Marc G. Brouwers, Amy Bonsor, Uri Malamud
Summary: Polluted white dwarfs act as astrophysical mass spectrometers, revealing the composition of accreted planetary material. Due to asymmetries in the accretion process, the composition of the falling material can vary with time, affecting the photospheric abundances. This study predicts that the core/mantle fraction of accreting material changes during tidal disruption events, making it difficult to determine the core fraction in white dwarfs with short diffusion time-scales.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
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
Zibo Liu, Dongdong Ni
Summary: This study focuses on a large sample of rocky exoplanets and calculates their bulk elemental abundance ratios. The quantitative correlation between rocky exoplanets and their host stars is analyzed by comparing the abundance ratios of these refractory elements. The results show that some rocky exoplanets have high iron-mass fractions, indicating they may be iron-enriched super-Mercuries. Furthermore, the iron content of rocky exoplanets is found to depend on the metallicity [Fe/H] of their host stars.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Claire Marie Guimond, Oliver Shorttle, John F. Rudge
Summary: Nominally anhydrous minerals in rocky planet mantles can store massive amounts of water, providing a constraint on planet water inventories. In this study, we predict the water capacities of silicate mantles based on the solubility of water in constituent minerals. We investigate the variability of mantle water capacities due to various factors and find that transition zone minerals dominate the water capacity for smaller planets, creating a potential bottleneck to deep water transport. The upper mantle becomes less important for larger planets. This work is important for understanding planetary water cycling, thermal evolution, and the frequency of ocean planets.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
P. S. Houdayer, D. R. Reese
Summary: This study presents the Rotation code Using Barotropy conservation over Isopotential Surfaces (RUBIS), a Python-based centrifugal deformation program that is publicly available. The program aims to calculate the centrifugal deformation of stars and planets based on a given cylindrical rotation profile, starting from a spherically symmetric non-rotating model. The underlying assumption in RUBIS is that the relationship between density and pressure is preserved during the deformation process, leading to procedural simplifications.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
G. Andama, N. Ndugu, S. K. Anguma, E. Jurua
Summary: In the classical picture of pebble-based core growth, planetary cores grow through accretion of single pebble species, reaching a pebble isolation mass that halts core growth. Recent hydrodynamic simulations show that core growth rates and final core masses are sensitive to parameters like turbulent viscosity and pebble size. Accretion of multiple pebble species can lead to fast growth of planetary cores, potentially explaining heavy element abundance in Jupiter, massive cores of extrasolar planets, disc rings and gaps at wider orbits, and early formation of planetary bodies.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Editorial Material
Astronomy & Astrophysics
Kazuhiro D. Kanagawa, Hidekazu Tanaka
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2020)
Article
Astronomy & Astrophysics
Kazuhiro D. Kanagawa, Jun Hashimoto, Takayuki Muto, Takashi Tsukagoshi, Sanemichi Z. Takahashi, Yasuhiro Hasegawa, Mihoko Konishi, Hideko Nomura, Hauyu Baobab Liu, Ruobing Dong, Akimasa Kataoka, Munetake Momose, Tomohiro Ono, Michael Sitko, Michihiro Takami, Kengo Tomida
Summary: The ALMA Band 6 observations of the disk around WW Cha reveal a smooth disk structure with a faint dust ring extending from about 40 au to 70 au, without any gap, and with two peaks at 40 au and 70 au. An analysis of the visibility data using a simple model and radiative transfer simulations suggest asymmetric structures in the disk, with temperatures around 30 K at the outer peak and 50 K at the inner peak, consistent with freezing temperatures of CO on water ice and H2S, respectively. The size distribution of dust grains was discussed based on spectral index maps obtained from the observations.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Hideko Nomura, Takashi Tsukagoshi, Ryohei Kawabe, Takayuki Muto, Kazuhiro D. Kanagawa, Yuri Aikawa, Eiji Akiyama, Satoshi Okuzumi, Shigeru Ida, Seokho Lee, Catherine Walsh, T. J. Millar
Summary: The study used high spatial resolution dust continuum observations and molecular line observations to confirm the physical and chemical structure models of the TW Hya disk, revealing specific gas and dust distributions in different parts of the disk. Significant differences in gas composition and intensity were observed at different radii within the disk. The research is important for understanding the disk-star system interaction in the process of planetary formation.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Kazuhiro D. Kanagawa, Takayuki Muto, Hidekazu Tanaka
Summary: When a planet forms a gap in a protoplanetary disk, a dust ring is formed, which is gradually deformed by viscous diffusion, and a new ring is formed near the migrating planet. This change in ring morphology can provide clues about the timing and location of planet formation.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Yuki A. Tanaka, Kazuhiro D. Kanagawa, Hidekazu Tanaka, Takayuki Tanigawa
Summary: Through two-dimensional numerical simulations, it was found that the eccentricity of the gap formed by a super-Jupiter-mass planet is related to the planetary mass and disk parameters. The critical planetary mass for eccentric gap formation is around 3 M (J). The eccentricity of the gap increases the surface density inside the gap and accelerates the mass accretion rate.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Shijie Wang, Kazuhiro D. Kanagawa, Yasushi Suto
Summary: Recent ALMA observations have identified various dust gaps in protoplanetary disks, with predictions of embedded planet masses depending on gap structures in both the dust and gas components. The study found that outer gaps are mostly dust alone, while inner gaps are more likely to be associated with a gas gap as well, indicating significant inward migration is required in the evolution of these embedded planets, which differs from observed planetary system architectures.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Takashi Tsukagoshi, Hideko Nomura, Takayuki Muto, Ryohei Kawabe, Kazuhiro D. Kanagawa, Satoshi Okuzumi, Shigeru Ida, Catherine Walsh, Tom J. Millar, Sanemichi Z. Takahashi, Jun Hashimoto, Taichi Uyama, Motohide Tamura
Summary: In this study, a high-resolution multiband analysis of the protoplanetary disk around TW Hya using ALMA long baseline data is presented. Two methods are employed to reconstruct the images and investigate the spectral index distribution. The results show that the multifrequency synthesis imaging method can accurately reproduce the frequency dependence of the continuum emission, while the image-oriented method provides consistent results but with lower resolution.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Shijie Wang, Kazuhiro D. Kanagawa, Yasushi Suto
Summary: Recent ALMA observations have revealed the presence of embedded protoplanets in a large number of disk substructures, providing valuable insights into the initial configurations and long-term orbital stability of these planetary systems. The results indicate that the disk-stage evolution and final configurations are influenced by initial mass assignments and viscosity. Moreover, it is found that strong perturbation sources like stellar flybys are required to drive the planetary system unstable after the disk stage.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
Yasuhiro Hasegawa, Kazuhiro D. Kanagawa, Neal J. Turner
Summary: Recent high-spatial/spectral-resolution observations have provided insights into the formation mechanisms of giant planets, with magnetospheric accretion playing a crucial role. These planets may possess dipole magnetic fields of varying strengths, influencing the properties of their circumplanetary disks and satellite formation processes.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Jiaqing Bi, Nienke van Der Marel, Ruobing Dong, Takayuki Muto, Rebecca G. Martin, Jeremy L. Smallwood, Jun Hashimoto, Hauyu Baobab Liu, Hideko Nomura, Yasuhiro Hasegawa, Michihiro Takami, Mihoko Konishi, Munetake Momose, Kazuhiro D. Kanagawa, Akimasa Kataoka, Tomohiro Ono, Michael L. Sitko, Sanemichi Z. Takahashi, Kengo Tomida, Takashi Tsukagoshi
ASTROPHYSICAL JOURNAL LETTERS
(2020)
Article
Astronomy & Astrophysics
Kazuhiro D. Kanagawa, Ewa Szuszkiewicz
ASTROPHYSICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Kazuhiro D. Kanagawa, Hideko Nomura, Takashi Tsukagoshi, Takayuki Muto, Ryohei Kawabe
ASTROPHYSICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Seongjoong Kim, Sanemichi Takahashi, Hideko Nomura, Takashi Tsukagoshi, Seokho Lee, Takayuki Muto, Ruobing Dong, Yasuhiro Hasegawa, Jun Hashimoto, Kazuhiro Kanagawa, Akimasa Kataoka, Mihoko Konishi, Hauyu Baobab Liu, Munetake Momose, Michael Sitko, Kengo Tomida
ASTROPHYSICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Shijie Wang, Kazuhiro D. Kanagawa, Toshinori Hayashi, Yasushi Suto
ASTROPHYSICAL JOURNAL
(2020)
Article
Astronomy & Astrophysics
Takashi Tsukagoshi, Takayuki Muto, Hideko Nomura, Ryohei Kawabe, Kazuhiro D. Kanagawa, Satoshi Okuzumi, Shigeru Ida, Catherine Walsh, Tom J. Millar, Sanemichi Z. Takahashi, Jun Hashimoto, Taichi Uyama, Motohide Tamura
ASTROPHYSICAL JOURNAL LETTERS
(2019)