Results 71 to 80 of about 902 (203)

Comets, volcanism, the salt-rich regolith, and cycling of volatiles on Mars [PDF]

Icarus, 1987
Abstract Estimates of the total inventory of the volatile elements C, H, O, and N on Mars, based upon atmospheric gas tracers, vary by a factor of 25 among different authors. Accretion of comets as the source of volatiles can account for less than 5% of the actual inventory, assuming the chondritic S/Cl abundance ratio in comets and a Martian ...
openaire   +1 more source

Early Stages of Galilean Moon Formation in a Water-depleted Environment

The Astrophysical Journal Letters, 2023
A key feature of the Galilean satellite system is its monotonic decrease in bulk density with growing distance from Jupiter, indicating an ice mass fraction that is zero in the innermost moon Io and about half in the outer moons Ganymede and Callisto ...
Olivier Mousis, A. Schneeberger, Jonathan I. Lunine, Christopher R. Glein, Alexis Bouquet, Steven D. Vance   +5 more
doaj   +1 more source

Effects of Comet Encke's Meteoroid Stream on the Seasonal Variation of Mercury's Ca Exosphere

Journal of Geophysical Research: Planets, Volume 131, Issue 6, June 2026.
Abstract Mercury's calcium (Ca) exosphere, observed by NASA's MESSENGER mission, exhibits high temperatures (>50000 K) and pronounced seasonal variability, with its source mainly on the dawn side. Enhanced Ca emission near True Anomaly Angle (TAA) ∼25° and ∼150° has been attributed to Comet 2P/Encke meteoroid streams.
M. Moroni, A. Milillo, A. Mura, A. A. Christou, P. Pokorný, V. Mangano, A. Berezhnoy, A. Aronica, A. Brin, E. De Angelis, P. P. Di Bartolomeo, A. Kazakov, S. Massetti, S. Orsini, C. Plainaki, G. Richards, R. Rispoli, R. Sordini, M. Stumpo   +18 more
wiley   +1 more source

The Rosetta mission orbiter science overview: the comet phase

, 2017
The international Rosetta mission was launched in 2004 and consists of the orbiter spacecraft Rosetta and the lander Philae. The aim of the mission is to map the comet 67P/Churyumov–Gerasimenko by remote sensing, and to examine its ...
M. G. G. T. Taylor, B. J. Buratti, N. Altobelli, M. Choukroun   +3 more
core   +1 more source

The Ice Composition Close to the Surface of Comet 67P/Churyumov-Gerasimenko

, 2022
: The relation between ice composition in the nucleus of comet 67P/Churyumov-Gerasimenko on the one hand and relative abundances of volatiles in the coma on the other hand is important for the interpretation of density measurements in the environment of ...
Tobias Kramer, Matthias Läuter, Läuter, Matthias, Martin Rubin, Kramer, Tobias, Rubin, Martin, Kathrin Altwegg, Altwegg, Kathrin   +7 more
core   +1 more source

The CAESAR New Frontiers Comet Sample Return Mission

, 2018
The Comet Astrobiology Exploration Sample Return (CAESAR) mission is one of two finalists selected by NASA for Phase A study in the New Frontiers program.
Dworkin, J. P., Nguyen, A., Milam, S., Hayes, A. G., Herd, C. D. K., Mitchell, D. F., Houghton, M., Zega, T. J., Lauretta, D. S., Nakamura-Messenger, K., Furukawa, Y., Messenger, S., Pace, L. F., Clemett, S., Blake, G., Takigawa, A., Nakamura, T., Mitchell, J., Squyres, S. W., Kimura, Y., Glavin, D. P., Mumma, M.   +21 more
core   +1 more source

Cryogenic Differential Calorimetry: Exothermicity of Amorphous-to-crystalline Phase Transitions (ACPT) in Astrophysical and Cometary Ice Analogs

The Astrophysical Journal
Amorphous ice is understood to be the predominant phase of water in cometary nuclei. A significant number of other volatiles can be trapped in amorphous H _2 O ice and released during the amorphous-to-crystalline phase transition (ACPT).
Rahul K. Kushwaha, Murthy S. Gudipati, Bryana L. Henderson   +2 more
doaj   +1 more source

Combustion and Pyrolysis EA‐IRMS Techniques to Determine the δ2H of Diamonds

Rapid Communications in Mass Spectrometry, Volume 40, Issue 10, 30 May 2026.
ABSTRACT Rationale Diamonds are generally considered to be metasomatic minerals originating from the Earth's mantle. They formed through the interaction of carbon‐bearing fluids or melts with the surrounding deep lithology. Most knowledge about the formation of diamonds comes from studying their mineral inclusions or stable isotopes.
François Fourel, Christophe Lécuyer, Emilie Thomassot, Etienne Deloule, Charles Ojeimi   +4 more
wiley   +1 more source

Modelling of the gas dynamics in the inner-coma and the composition of comet 67P/Churyumov-Gerasimenko

, 2021
This thesis presents a study of the gas dynamics of cometary nuclei with a focus on the target of the Rosetta mission, comet 67P/Churyumov-Gerasimenko. We therefore apply the 3D Direct Simulation Monte Carlo (DSMC) method to different distributions of ...
Pinzón Rodriguez, Olga Janeth
core  

Covertly Active Comet (139359) 2001 ME1

The Planetary Science Journal
On 2018 November 18, coronagraphs onboard the Solar and Heliospheric Observatory (SOHO) captured an unrecognized comet crossing its fields of view. We identified this comet to be the minor planet (139359) 2001 ME _1 , whose previously unnoticed dust ...
Qicheng Zhang, Quanzhi Ye, Karl Battams, Matthew M. Knight, Worachate Boonplod, Rainer Kracht   +5 more
doaj   +1 more source