Featured
-
-
Letter |
Remote sensing evidence for an ancient carbon-bearing crust on Mercury
Mercury appears darker globally than expected. Remote sensing evidence from the MESSENGER spacecraft indicates that the planet’s darkening agent is carbon and suggests that it originates from an ancient graphite-rich crust.
- Patrick N. Peplowski
- , Rachel L. Klima
- & Sean C. Solomon
-
Perspective |
The demise of Phobos and development of a Martian ring system
The moon Phobos will eventually either disintegrate to form a ring or crash into Mars. Observational constraints and geotechnical considerations suggest that Phobos will partially break apart into a ring, with stronger fragments impacting Mars.
- Benjamin A. Black
- & Tushar Mittal
-
News & Views |
Cooking up the Moon in two steps
Compared to Earth, the Moon is depleted in volatile species like water, sodium and potassium. Simulations suggest that much of the Moon formed from hot, volatile-poor melt in a disk of debris after initially amassing cooler, volatile-rich melt.
- Steve Desch
-
Letter |
Lunar volatile depletion due to incomplete accretion within an impact-generated disk
The Moon may have accreted from a disk of debris after a giant impact. Simulations suggest that part of the Moon derives from volatile-poor melt in the hot inner disk, with most of the volatile elements condensing later and accreting to Earth.
- Robin M. Canup
- , Channon Visscher
- & Bruce Fegley Jr
-
Review Article |
Nitrogen isotope variations in the Solar System
The solar wind, cometary ices, and inner Solar System bodies exhibit distinct nitrogen isotopic compositions. A synthesis of these analyses suggests that these distinct reservoirs may be the result of early fractionation processes.
- Evelyn Füri
- & Bernard Marty
-
News & Views |
Iron fog of accretion
Pinpointing when Earth's core formed depends on the extent of metal–silicate equilibration in the mantle. Vaporization and recondensation of impacting planetesimal cores during accretion may reconcile disparate lines of evidence.
- William W. Anderson
-
Letter |
Impact vaporization of planetesimal cores in the late stages of planet formation
Differentiated planetesimals may have delivered iron-rich material to Earth in giant impacts at the end of accretion. Impact experiments suggest that the planetesimals’ iron cores vaporized, aiding dispersal and mixing into Earth’s mantle.
- Richard G. Kraus
- , Seth Root
- & Thomas R. Mattsson
-
Letter |
Water contents of Earth-mass planets around M dwarfs
Faint M dwarf stars are the focus of searches for habitable planets. Numerical models suggest that changes in stellar luminosity lead to planets that are either too dry or too wet to be habitable in M dwarf systems.
- Feng Tian
- & Shigeru Ida
Accretion of Phobos and Deimos in an extended debris disc stirred by transient moons