Article
Astronomy & Astrophysics
F. Ahlborn, E. P. Bellinger, S. Hekker, S. Basu, D. Mokrytska
Summary: This study proposes a new method to improve the measurement accuracy of surface rotation rates in red giant stars, allowing for better constraints on the internal rotation processes. By combining this method with independent measurements of surface rotation rates, a better understanding of the internal angular momentum transport along the lower part of the red-giant branch can be achieved.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Environmental Sciences
Nancy J. Chanover, James M. Bauer, John J. Blalock, Mitchell K. Gordon, Lyle F. Huber, Mia J. T. Mace, Lynn D. V. Neakrase, Matthew S. Tiscareno, Raymond J. Walker
Summary: While fewer missions have been conducted to the outer Solar System compared to the inner Solar System, these missions to the giant planets have provided valuable data that continue to shape our understanding of these complex systems. The data are stored in national and international planetary archives and can be accessed through the NASA Planetary Data System (PDS). The PDS will serve as the main repository for future missions' data and support research on the interpretation of the existing data.
Article
Astronomy & Astrophysics
Lucy O. McNeill, Bernhard Muller
Summary: The study reveals a quasi-stationary pattern of differential rotation in the convective oxygen shell of a rapidly rotating helium star, with a positive angular velocity gradient. The findings challenge current stellar evolution models and have implications for the formation of millisecond magnetars and neutron star birth spin periods. Future simulations will need to explore in more detail how buoyancy, inertial forces, and turbulent stresses shape differential rotation during late-stage convection in massive stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
R. W. Dymott, A. J. Barker, C. A. Jones, S. M. Tobias
Summary: We investigate the linear and non-linear properties of the Goldreich-Schubert-Fricke (GSF) instability in stellar radiative zones with arbitrary local differential rotation. This instability may lead to turbulence that contributes to the redistribution of angular momentum and chemical composition in stars. Our analysis explores the effects of orientation of the shear with respect to the 'effective gravity' and the hydrodynamical evolution in three dimensions using a modified shearing box. This study provides insights into the transport properties of the GSF instability and its potential contribution to angular momentum transport in stars.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Physics, Multidisciplinary
Sergey Ershkov, Dmytro Leshchenko, Elbaz Abouelmagd
Summary: The study examines the effects of tidal interactions and differential rotation on the orbital evolution of Uranus satellites, finding that the differential rotation effect has minimal contribution in the Uranus system. Uranus is considered suitable for applying modern ansatz to analyze the characteristics of satellite orbits, with internal heat generation effects primarily occurring within the satellites.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Astronomy & Astrophysics
Melissa J. Hobson, Rafael Brahm, Andres Jordan, Nestor Espinoza, Diana Kossakowski, Thomas Henning, Felipe Rojas, Martin Schlecker, Paula Sarkis, Trifon Trifonov, Daniel Thorngren, Avraham Binnenfeld, Sahar Shahaf, Shay Zucker, George R. Ricker, David W. Latham, S. Seager, Joshua N. Winn, Jon M. Jenkins, Brett Addison, Francois Bouchy, Brendan P. Bowler, Joshua T. Briegal, Edward M. Bryant, Karen A. Collins, Tansu Daylan, Nolan Grieves, Jonathan Horner, Chelsea Huang, Stephen R. Kane, John Kielkopf, Brian McLean, Matthew W. Mengel, Louise D. Nielsen, Jack Okumura, Matias Jones, Peter Plavchan, Avi Shporer, Alexis M. S. Smith, Rosanna Tilbrook, C. G. Tinney, Joseph D. Twicken, Stephane Udry, Nicolas Unger, Richard West, Robert A. Wittenmyer, Bill Wohler, Pascal Torres, Duncan J. Wright
Summary: TOI-201 b is an eccentric warm giant planet orbiting a young, bright F-type star, which is important for constraining formation and evolution theories for giant planets.
ASTRONOMICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
F. D. Moyano, P. Eggenberger, G. Meynet, C. Gehan, B. Mosser, G. Buldgen, S. J. A. J. Salmon
Summary: In this paper, the efficiency of internal angular momentum redistribution in red giants during the hydrogen-shell and core-helium burning phases was investigated based on asteroseismic determinations of their core rotation rates. It was found that the additional viscosity required for angular momentum transport varies with stellar mass and evolutionary stage, with higher efficiencies needed in more massive stars and older red clump stars.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Yu-Cian Hong, Dong Lai, Jonathan Lunine, Philip D. Nicholson
Summary: The study indicates that planet-planet scattering can cause the spin of planets to evolve, resulting in potentially large obliquities. The evolution of planet spin is mainly influenced by the torque from the central star.
ASTROPHYSICAL JOURNAL
(2021)
Article
Astronomy & Astrophysics
Aneta Wojnar
Summary: The study focuses on the critical core mass and the conditions for a planet to possess a massive gaseous envelope around a solid core during early planetary formation.
Review
Environmental Sciences
Csaba Palotai, Shawn Brueshaber, Ramanakumar Sankar, Kunio Sayanagi
Summary: The atmospheres of the outer planets in our Solar System exhibit a wide array of intriguing cloud features, varying in color and size. The distinct differences in cloud types observed suggest a complex interplay between the dynamics and chemistry at play in these atmospheres. The contrasting banded structures of Jupiter and Saturn compared to the sporadic clouds on the ice giants highlight the diverse dynamic, chemical, and thermal processes shaping these atmospheres. This review presents evidence of moist convective activity in the gas giant atmospheres of our Solar System through remote sensing data from both ground- and space-based observations. The processes driving moist convective activity, including dynamics and microphysics shaping the resulting clouds, are discussed, as well as the effects of moist convection on large-scale dynamics such as jet structures on these planets.
Article
Astronomy & Astrophysics
T. Constantino, I Baraffe, T. Goffrey, J. Pratt, T. Guillet, D. G. Vlaykov, L. Amard
Summary: Researchers utilized rotating 1D stellar evolution models to study the evolution of stars, incorporating modifications to the temperature gradient in convection zones and a criterion for convective instability inspired by rotating 3D hydrodynamical simulations. By suppressing convection and modifying the temperature gradient, they were able to simulate lithium depletion in rapidly rotating stars, matching observations of lithium spread in young open clusters.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Multidisciplinary Sciences
Geoffrey M. Vasil, Keith Julien, Nicholas A. Featherstone
Summary: The lack of giant convection cells near the Sun's outer surface has puzzled solar modelers for a long time. The study proposes an explanation, suggesting that rotation strongly influences internal dynamics and leads to suppressed convective velocities. It predicts a characteristic convection length scale of approximately 30 Mm and a dynamical Rossby number less than unity below the near-surface shear layer.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Astronomy & Astrophysics
A. Claret
Summary: The aim of this study was to investigate the nuclear and tidal evolution of the double-lined eclipsing binary system TZ Fornacis. The results showed good agreement between the predicted values of the system's evolution and the observed values. The friction timescale was found to have a significant impact on the orbital elements of the system.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
David Nesvorny, Fernando V. Roig, Rogerio Deienno
Summary: The terrestrial planets are believed to have formed by violent collisions of tens of lunar- to Mars-size protoplanets within 200 million years after the dispersal of the protoplanetary gas disk. The rapid formation and radial migration of the solar system giant planets may have influenced the formation of the terrestrial planets.
ASTRONOMICAL JOURNAL
(2021)
Article
Multidisciplinary Sciences
Marc Hon, Daniel Huber, Nicholas Z. Rui, Jim Fuller, Dimitri Veras, James S. Kuszlewicz, Oleg Kochukhov, Amalie Stokholm, Jakob Lysgaard Rorsted, Mutlu Yildiz, Zeynep Celik Orhan, Sibel Ortel, Chen Jiang, Daniel R. Hey, Howard Isaacson, Jingwen Zhang, Mathieu Vrard, Keivan G. Stassun, Benjamin J. Shappee, Jamie Tayar, Zachary R. Claytor, Corey Beard, Timothy R. Bedding, Casey Brinkman, Tiago L. Campante, William J. Chaplin, Ashley Chontos, Steven Giacalone, Rae Holcomb, Andrew W. Howard, Jack Lubin, Mason MacDougall, Benjamin T. Montet, Joseph M. A. Murphy, Joel Ong, Daria Pidhorodetska, Alex S. Polanski, Malena Rice, Dennis Stello, Dakotah Tyler, Judah Van Zandt, Lauren M. Weiss
Summary: When main-sequence stars evolve into red giants, they are expected to engulf nearby planets. The absence of short-period planets around core-helium-burning red giants has been considered as evidence that these planets do not survive the expansion phase of their host stars. However, the discovery of the giant planet 8 Ursae Minoris b orbiting a core-helium-burning red giant challenges this interpretation. The system suggests that non-canonical stellar evolution plays a role in the extended survival of late-stage exoplanetary systems.