Results 21 to 30 of about 2,834 (210)

The chronostratigraphy of protoplanet Vesta [PDF]

Icarus, 2014
In this paper we present a time-stratigraphic scheme and geologic time scale for the protoplanet Vesta, based on global geologic mapping and other analyses of NASA Dawn spacecraft data, complemented by insights gained from laboratory studies of howardite–eucrite–diogenite (HED) meteorites and geophysical modeling.
Williams, D.A., Jaumann, R., McSween, H.Y., Marchi, S., Schmedemann, N., Raymond, C.A., Russell, C.T.   +6 more
openaire   +3 more sources

Protoplanet collisions: Statistical properties of ejecta [PDF]

Monthly Notices of the Royal Astronomical Society, 2021
ABSTRACT The last phase of the formation of rocky planets is dominated by collisions among Moon- to Mars-sized planetary embryos. Simulations of this phase need to handle the difficulty of including the post-impact material without saturating the numerical integrator.
Samuele Crespi, Ian Dobbs-Dixon, Nikolaos Georgakarakos, Nader Haghighipour, Thomas I Maindl, Christoph M Schäfer, Philip Matthias Winter   +6 more
openaire   +2 more sources

Ultrahigh‐Pressure Acoustic Velocities of Aluminous Silicate Glass up to 155 GPa With Implications for the Structure and Dynamics of the Deep Terrestrial Magma Ocean

Geophysical Research Letters, Volume 50, Issue 14, 28 July 2023., 2023
Abstract We have carried out in situ high‐pressure acoustic velocity measurements of (Fe2+, Al)‐bearing MgSiO3 glass up to pressures of 155 GPa, which confirmed a distinct pressure‐induced trend change in the transverse acoustic velocity (VS) profile around 98 GPa, likely caused by the Si‐O coordination number (CN) change from 6 to 6+.
Pinku Saha, Motohiko Murakami, Catherine McCammon, Christian Liebske, Ewa Krymarys   +4 more
wiley   +1 more source

An Evolved Early Crust Exposed on Mars Revealed Through Spectroscopy

Geophysical Research Letters, Volume 49, Issue 21, 16 November 2022., 2022
Abstract Mars early crust is more complex than homogenously basaltic with evolved magmatism evidenced by intermediate and felsic igneous rocks found in various locations in the southern hemisphere and martian meteorites. Geophysical constraints argue against a dense thick basaltic crust in the southern hemisphere, rather consistent with a buried light ...
V. Payré, M. R. Salvatore, C. S. Edwards   +2 more
wiley   +1 more source

Shock degree and graphite geothermometry in ureilites NWA 6871 and NWA 3140

Meteoritics &Planetary Science, Volume 57, Issue 10, Page 1861-1878, October 2022., 2022
Abstract Carbon aggregates from two differently shocked ureilites were analyzed to gain insight into the shock transformation of graphite to diamond in ureilites, which happened when the ureilite parent body (UPB) was most likely destroyed by massive impact events.
Oliver Christ, Anna Barbaro, Frank E. Brenker, Paolo Nimis, Davide Novella, M. Chiara Domeneghetti, Fabrizio Nestola   +6 more
wiley   +1 more source

InSight Constraints on the Global Character of the Martian Crust

Journal of Geophysical Research: Planets, Volume 127, Issue 5, May 2022., 2022
Abstract Analyses of seismic data from the InSight mission have provided the first in situ constraints on the thickness of the crust of Mars. These crustal thickness constraints are currently limited to beneath the lander that is located in the northern lowlands, and we use gravity and topography data to construct global crustal thickness models that ...
Mark A. Wieczorek, Adrien Broquet, Scott M. McLennan, Attilio Rivoldini, Matthew Golombek, Daniele Antonangeli, Caroline Beghein, Domenico Giardini, Tamara Gudkova, Szilárd Gyalay, Catherine L. Johnson, Rakshit Joshi, Doyeon Kim, Scott D. King, Brigitte Knapmeyer‐Endrun, Philippe Lognonné, Chloé Michaut, Anna Mittelholz, Francis Nimmo, Lujendra Ojha, Mark P. Panning, Ana‐Catalina Plesa, Matthew A. Siegler, Suzanne E. Smrekar, Tilman Spohn, W. Bruce Banerdt   +25 more
wiley   +1 more source

Primordial Helium‐3 Exchange Between Earth's Core and Mantle

Geochemistry, Geophysics, Geosystems, Volume 23, Issue 3, March 2022., 2022
Abstract Volatiles from the solar nebula are known to be present in Earth's deep mantle. The core also may contain solar nebula‐derived volatiles, but in unknown amounts. Here we use calculations of volatile ingassing and degassing to estimate the abundance of primordial 3He now in the core and track the rate of 3He exchange between the core and mantle
Peter L. Olson, Zachary D. Sharp
wiley   +1 more source

Detecting protoplanets with ALMA [PDF]

Astrophysics and Space Science, 2007
Theoretical investigations show that planet-disk interactions cause structures in circumstellar disks, which are usually much larger in size than the planet itself and thus more easily detectable. The specific result of planet-disk interactions depends on the evolutionary stage of the disk. Exemplary signatures of planets embedded in disks are gaps and
openaire   +1 more source

Kinematic Evidence of an Embedded Protoplanet in HD 142666 Identified by Machine Learning

The Astrophysical Journal, 2023
Observations of protoplanetary disks have shown that forming exoplanets leave characteristic imprints on the gas and dust of the disk. In the gas, these forming exoplanets cause deviations from Keplerian motion, which can be detected through molecular ...
J. P. Terry, C. Hall, S. Abreau, S. Gleyzer   +3 more
doaj   +1 more source

The formation of Uranus and Neptune among Jupiter and Saturn [PDF]

, 2001
The outer giant planets, Uranus and Neptune, pose a challenge to theories of planet formation. They exist in a region of the Solar System where long dynamical timescales and a low primordial density of material would have conspired to make the formation ...
E. W. Thommes, Eberhardt P., Fernandez J. A., Feuchtgruber H., Guillot T., H. F. Levison, Ipatov S. I., Kokubo E., Lin D. N. C., M. J. Duncan, Malhotra R., Weidenschilling S. J., Zharkov V. N.   +12 more
core   +2 more sources