Results 61 to 70 of about 586,778 (202)

Polluting White Dwarfs with Oort Cloud Comets [PDF]

Observations point to old white dwarfs (WDs) accreting metals at a relatively constant rate over 8~Gyrs. Exo-Oort clouds around WDs have been proposed as potential reservoirs of materials, with galactic tide as a mechanism to deliver distant comets to ...
Rein, Hanno, Pham, Dang
core   +1 more source

Nearby Supernova and Cloud Crossing Effects on the Orbits of Small Bodies in the Solar System

The Astrophysical Journal Letters
Supernova (SN) blasts envelop many surrounding stellar systems, transferring kinetic energy to small bodies in the systems. Geologic evidence from ^60 Fe points to recent nearby SN activity within the past several Myr.
Leeanne Smith, Jesse A. Miller, Brian D. Fields   +2 more
doaj   +1 more source

Coma Abundances of Volatiles at Small Heliocentric Distances: Compositional Measurements of Long-period Comet C/2020 S3 (Erasmus)

The Astronomical Journal, 2023
We report production rates of H _2 O and nine trace molecules (C _2 H _6 , CH _4 , H _2 CO, CH _3 OH, HCN, NH _3 , C _2 H _2 , OCS, and CO) in long-period comet C/2020 S3 (Erasmus) using the high-resolution, cross-dispersed infrared spectrograph (iSHELL)
Chemeda Ejeta, Erika Gibb, Nathan Roth, Michael A. DiSanti, Neil Dello Russo, Mohammad Saki, Adam J. McKay, Hideyo Kawakita, Younas Khan, Boncho P. Bonev, Ronald J. Vervack Jr., Michael R. Combi   +11 more
doaj   +1 more source

Defining soil: Proposals of zero‐states, active layer, and págousols (from ice parent materials) to fundamentally expand soil science

Soil Science Society of America Journal, Volume 90, Issue 2, March/April 2026.
Abstract Recent publications in soil science have reopened discussions over how soil and soil science should be defined, reflecting productive tension between historical constructs and the evolving frontiers of the discipline. While new definitions offered over the past decade provide valuable perspectives, they inevitably rely on past conventions and ...
Aaron Lee M. Daigh
wiley   +1 more source

On the Origin of Sodium Atoms in the Comae and Trails of Comets

Universe
Background: The observed abundance ratios of alkali species in ground-based spectra of comets deviate from solar composition, suggesting alkali ejection from phenoxides reacting with carbon dioxide at the nucleus surface (alkali-phenoxide carbonylation).
Marco Fulle, Paolo Molaro, Ilya Ilyin
doaj   +1 more source

First Coincident Radar and Optical Observations of a Meteor Radio Afterglow

Journal of Geophysical Research: Space Physics, Volume 131, Issue 3, March 2026.
Abstract It has been hypothesized that Meteor Radio Afterglows (MRAs) occur due to resonant transition radiation (RTR) where suprathermal electrons emit as they pass through electron density inhomogeneities in a turbulent plasma. Meteor trails are thought to produce suprathermal electrons through anion oxidation, which can be identified through meteor ...
K. S. Obenberger, J. L. Chau, J. Vierinen, D. Vida, L. E. Cordonnier, Z. Balint, M. Clahsen, E. Dao, J. Dowell, J. M. Holmes, R. F. Kelly, D. Kastinen, N. Pfeffer, K. Robinson, G. B. Taylor, J. M. Urco   +15 more
wiley   +1 more source

What long-period comets tell us about the Oort Cloud

, 2023
Context. The Oort Cloud is located in the farthest outskirts of the Solar System, extending to a heliocentric distance of several tens of thousands of au, and remains the last region of the Solar System where no object has been detected.
Arika Higuchi, Takashi Ito, Ito, Takashi, Higuchi, Arika, Fouchard, Marc, Marc Fouchard   +5 more
core   +1 more source

Dust and Volatiles in the Disintegrating Comet C/2019 Y4 (ATLAS)

The Astrophysical Journal
C/2019 Y4 (ATLAS) is an Oort cloud comet with an orbital period of ∼5895 yr. Starting in 2020 March, its nucleus underwent disintegration. In order to investigate the gas and dust properties of C/2019 Y4 (ATLAS) during its disintegration, we obtained ...
Ruining Zhao, Aigen Li, Bin Yang, Liang Wang, Huijuan Wang, Yu-Juan Liu, Jifeng Liu   +6 more
doaj   +1 more source

Some Studies of Terrestrial Impact Cratering Rate

Open Astronomy, 2011
In 1984, a 28.4 Myr periodicity was detected in the ages of terrestrial impact craters and a 26 Myr periodicity in the epochs of mass extinctions of species.
Jetsu L.
doaj   +1 more source

Accurate Column Moist Static Energy Budget in Climate Models. Part 1: Conservation Equation Formulation, Methodology, and Primary Results Demonstrated Using GISS ModelE3

Journal of Advances in Modeling Earth Systems, Volume 18, Issue 3, March 2026.
Abstract Column‐integrated moist static energy (MSE) budgets underpin theories of tropical convection and circulation, yet in reanalyses and climate models the budget rarely closes; residuals routinely match the leading terms and mask physical insights.
Kuniaki Inoue, Maxwell Kelley, Ann M. Fridlind, Michela Biasutti, Gregory S. Elsaesser   +4 more
wiley   +1 more source