Results 31 to 40 of about 126 (111)

Helium in Mercury's Extended Exosphere Determined by Pick‐Up Generated Ion Cyclotron Waves

open access: yesJournal of Geophysical Research: Planets, Volume 130, Issue 4, April 2025.
Abstract Helium (He) was first detected by remote spectroscopic observations of the Ultraviolet Visible Spectrometers (UVVS) instrument in Mercury's exosphere during the three Mariner 10 flybys in 1974 and 1975. Here, we derive the first in situ radial density profile of He in Mercury's extended exosphere by analyzing magnetic field and plasma ...
F. Weichbold   +8 more
wiley   +1 more source

Ion‐Scale Characteristics of the Martian Magnetic Pile‐Up Boundary Layer

open access: yesGeophysical Research Letters, Volume 52, Issue 3, 16 February 2025.
Abstract The Martian magnetic pile‐up boundary (MPB) delineates the interface between the magnetosheath and the induced magnetosphere, but its global ion‐scale characteristics remaining unclear. Utilizing a three‐dimensional Hall magnetohydrodynamic (MHD) model, this study aims to reveal the features of the MPB layer, including magnetic field, current ...
Shibang Li   +12 more
wiley   +1 more source

Seasonal and Local Time Variation in the Observed Peak of the Meteor Altitude Distributions by Meteor Radars

open access: yesJournal of Geophysical Research: Atmospheres, Volume 129, Issue 21, 16 November 2024.
Abstract Meteoroids of sub‐milligram sizes burn up high in the Earth's atmosphere and cause streaks of plasma trails detectable by meteor radars. The altitude at which these trails, or meteors, form depends on a number of factors including atmospheric density and the astronomical source populations from which these meteoroids originate.
E. C. M. Dawkins   +26 more
wiley   +1 more source

Coordinated programs for comet Halley [PDF]

open access: yesSymposium - International Astronomical Union, 1986
Because comets are so difficult to observe, it is essential to coordinate observations from a variety of telescopes in order to fully understand their behavior. The apparition of Comet Halley represents a unique opportunity for coordinated programs because this is the only predictable comet which is routinely bright enough for the many observational ...
openaire   +1 more source

The dynamical history of comet Halley [PDF]

open access: yesInternational Astronomical Union Colloquium, 1985
AbstractThe history of the attempts to predict the motion of comet Halley is outlined and the importance of the so-called nongravitational forces acting upon this comet is emphasized. Recent orbital work of the International Halley Watch Astrometry Network is reviewed. Comet Halley’s transverse nongravitational parameter is positive and nearly constant
openaire   +1 more source

The Past Orbit of Halley's Comet [PDF]

open access: yesMonthly Notices of the Royal Astronomical Society, 1972
I have re-examined the records in the Chinese“Standard Histories”on this famous object, including one set of relatively precise observations made in the year 837 A.D., which has only recently become available in an English translation (Ho 1962). This set, when properly interpreted, consists of the comet’s right ascension on 10 specified dates, given to
openaire   +1 more source

87th Annual Meeting of the Meteoritical Society 2025: Abstracts

open access: yes
Meteoritics &Planetary Science, Volume 60, Issue S1, Page 30-350, August 2025.
wiley   +1 more source

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