Related papers: A nitrogen-rich atmosphere on ancient Mars consist…
One-third of Mars' surface has shallow-buried H$_2$O, but it is currently too cold for use by life. Proposals to warm Mars using greenhouse gases require a large mass of ingredients that are rare on Mars' surface. However, we show here that…
The first in-situ measurements of the altitude profile of Martian upper atmospheric density and composition were carried out by the Viking lander missions in 1976. The MAVEN and MOM spacecraft launched in September 2014 with mass…
We present a comprehensive study of the abundance of carbon dioxide in exoplanetary atmospheres in hot, hydrogen-dominated atmospheres. We construct novel analytical models of systems in chemical equilibrium that include carbon monoxide,…
Radiometric dating indicates that Mars accreted in the first ~4 Myr of solar system formation, which coincides with the formation and possible migration of Jupiter. While nebular gas from the protoplanetary disk was still present, Jupiter…
Titan's abundant atmospheric N2 and CH4 gases are notable characteristics of the moon that may help constrain its origins and evolution. Previous work suggests that atmospheric CH4 is lost on geologically short timescales and may be…
Despite a fainter Sun, the surface of the early Earth was mostly ice-free. Proposed solutions to this so-called "faint young Sun problem" have usually involved higher amounts of greenhouse gases than present in the modern-day atmosphere.…
Near-surface perennial water ice on Mars has been previously inferred down to latitudes of about 45{\deg} and could result from either water vapor diffusion through the regolith under current conditions or previous ice ages precipitations.…
The decline of Mars' global magnetic field some 3.8-4.1 billion years ago is thought to reflect the demise of the dynamo that operated in its liquid core. The dynamo was probably powered by planetary cooling and so its termination is…
Atmospheric nitrogen may provide important constraints on giant planet formation. Following our semi-analytical work (Ohno & Fortney 2022), we further pursue the relation between observable NH3 and an atmosphere's bulk nitrogen abundance by…
Conventional planet formation theory suggests that chondritic materials have delivered crucial atmospheric and hydrospheric elements such as carbon (C), nitrogen (N), and hydrogen (H) onto primitive Earth. However, recent measurements…
Terrestrial exoplanets likely form initial atmospheres through outgassing during and after accretion, although there is currently no first-principles understanding of how to connect a planet's bulk composition to its early atmospheric…
We propose a scenario that explains the apparent nitrogen deficiency in comets in a way consistent with the fact that the surfaces of Pluto and Triton are dominated by nitrogen-rich ice. We use a statistical thermodynamic model to…
Mars was characterized by cataclysmic groundwater-sourced surface flooding that formed large outflow channels and that may have altered the climate for extensive periods during the Hesperian era. In particular, it has been speculated that…
The evolution of exoplanetary atmospheres is strongly influenced by atmospheric escape, particularly for close-in planets. Fractionation during atmospheric loss can preferentially remove lighter elements such as hydrogen, while retaining…
MESSENGER observations suggest a magma ocean formed on proto-Mercury, during which evaporation of metals and outgassing of C- and H-bearing volatiles produced an early atmosphere. Atmospheric escape subsequently occurred by plasma heating,…
This review describes the dynamic phenomena in the atmosphere of Mars that are visible in images taken in the visual range through cloud formation and dust lifting. We describe the properties of atmospheric features traced by aerosols…
A model for the formation and distribution of sedimentary rocks on Mars is proposed. The rate-limiting step is supply of liquid water from seasonal melting of snow or ice. The model is run for a O(10^2) mbar pure CO2 atmosphere, dusty snow,…
The availability of Martian atmospheric data provided by several Martian missions broadened the opportunity to investigate and study the conditions of the Martian ionosphere. As such, ionospheric models play a crucial part in improving our…
Mars' thin, CO$_2$-rich atmosphere poses a unique puzzle involving composition, climate history, and habitability. This work explores the intrincate relationship between Mars' atmospheric variations and dynamic solar activity patterns. We…
Recent new high-precision abundance data for Galactic halo stars suggest important primary nitrogen production in very metal-poor massive stars. Here, we compute a new model for the chemical evolution of the Milky Way aimed at explaining…