Ana-Catalina Plesa

German Aerospace Center (DLR) | DLR · Department of Planetary Physics

Plain Language Summary On Venus, convective up and downwellings in the mantle are intrinsically linked to density variations in the interior. The manner in which the planet is deformed by these mantle flows depends upon its viscosity, and this in turn affects the gravity and topography signals that were recorded by orbiting spacecraft. We tested a...

Plain Language Summary The NASA InSight mission and its seismometer installed on the surface of Mars is retired after ∼4 years of operation. From the largest marsquake recording during the entire mission, we observe clear seismic signals from surface waves called Rayleigh waves that orbit around Mars up to three times. By measuring the wavespeeds w...

The seismic activity of a planet can be described by the corner magnitude, events larger than which are extremely unlikely, and the seismic moment rate, the long‐term average of annual seismic moment release. Marsquake S1222a proves large enough to be representative of the global activity of Mars and places observational constraints on the moment r...

There is a growing consensus that Venus is seismically active, although its level of seismicity could be very different from that of Earth due to the lack of plate tectonics. Here, we estimate upper and lower bounds on the expected annual seismicity of Venus by scaling the seismicity of the Earth. We consider different scaling factors for different...

The composition of basaltic melts in equilibrium with the mantle can be determined for several Martian meteorites and in-situ rover analyses. We use the melting model MAGMARS to reproduce these primary melts and estimate the bulk composition and temperature of the mantle regions from which they originated. We find that most mantle sources are deple...

We report observations of Rayleigh waves that orbit around Mars up to three times following the S1222a marsquake. Averaging these signals, we find the largest amplitude signals at 30 s and 85 s central period, propagating with distinctly different group velocities of 2.9 km/s and 3.8 km/s, respectively. The group velocities constraining the average...

Here we examine how our knowledge of present day Venus can inform terrestrial exoplanetary science and how exoplanetary science can inform our study of Venus. In a superficial way the contrasts in knowledge appear stark. We have been looking at Venus for millennia and studying it via telescopic observations for centuries. Spacecraft observations be...

Magnetic field observations from the MGS, MAVEN, and InSight missions reveal that a dynamo was active in Mars’s early history. One unique feature of Mars’s magnetic crustal field is its hemispheric dichotomy, where magnetic fields in the southern hemisphere are much stronger than those in the northern hemisphere. Here we use numerical dynamo simula...

Ice-covered ocean worlds, such as the Jovian moon Europa, are some of the prime targets for planetary exploration due to their high astrobiological potential. While upcoming space exploration missions, such as the Europa Clipper and JUICE missions, will give us further insight into the local cryoenvironment, any conclusive life detection investigat...

Often termed the twin sister of the Earth, Venus represents an alternative outcome of the thermal evolution of an Earth-sized planet. Its extreme surface pressure and temperature, combined with the absence of plate tectonics as we know it, produced a barren, infernal world hidden under a thick atmosphere. Venus also remains the most enigmatic of te...

The dynamics and evolution of Venus’ mantle are of first-order relevance for the origin and modification of the tectonic and volcanic structures we observe on Venus today. Solid-state convection in the mantle induces stresses into the lithosphere and crust that drive deformation leading to tectonic signatures. Thermal coupling of the mantle with th...

We compare several recent Martian interior models and evaluate how these are impacted by the tidal constraints provided by the Love number k2 and the secular acceleration in longitude s of its main moon, Phobos. The expression of the latter is developed up to harmonic degree 5 to match the accuracy of the current observations. We match a number of...

We detected surface waves from two meteorite impacts on Mars. By measuring group velocity dispersion along the impact-lander path, we obtained a direct constraint on crustal structure away from the InSight lander. The crust north of the equatorial dichotomy had a shear wave velocity of approximately 3.2 kilometers per second in the 5- to 30-kilomet...

Constraining the thermal and compositional state of the mantle is crucial for deciphering the formation and evolution of Mars. Mineral physics predicts that Mars' deep mantle is demarcated by a seismic discontinuity arising from the pressure-induced phase transformation of the mineral olivine to its higher-pressure poly-morphs, making the depth of...

This work reviews the long-term evolution of the atmosphere of Venus, and modulation of its composition by interior/exterior cycling. The formation and evolution of Venus’s atmosphere, leading to contemporary surface conditions, remain hotly debated topics, and involve questions that tie into many disciplines. We explore these various inter-related...

We discuss two parameterisations of the popular Andrade rheological model that appear in planetological literature and illustrate how different assumptions affect the estimates of tidal dissipation and Love numbers.

We discuss two parameterisations of the popular Andrade rheological model that appear in planetological literature and illustrate how different assumptions affect the estimates of tidal dissipation and Love numbers.

Due to the Moon-forming impact the Moon was initially covered by a global magma ocean. Cooling and subsequent fractional solidification led to an initially layered lunar mantle composition. The aim of our work is to investigate how this mantle composition affects the convection and the subsequent melting of the lunar mantle. In our work we use the...

When NASA’s InSight lander touched down in Elysium Planitia, Mars, in November 2018 and deployed its seismometer SEIS, it ushered in a new age for planetary seismology - more than 40 years after the first attempt to record marsquakes with the Viking missions. SEIS, an extremely sensitive instrument, has by now provided near continuous seismic recor...

Bodily tides provide key information on the interior structure, evolution, and origin of the planetary bodies. Our Solar system harbors a very diverse population of planetary bodies, including those composed of rock, ice, gas, or a mixture of all. While a rich arsenal of geophysical methods has been developed over several years to infer knowledge a...

Over the past decades, global geodynamic models have been used to investigate the thermal evolution of terrestrial planets. With the increase of computational power and improvement of numerical techniques, these models have become more complex, and simulations are now able to use a high resolution 3D spherical shell geometry and to account for stro...

Large-scale numerical simulations of planetary interiors require dedicated visualization algorithms that are able to efficiently extract a large amount of information in an interactive and user-friendly way. Here we present a software framework for the visualization of mantle convection data. This framework combines real-time volume rendering, path...

Over the past decades, global geodynamical models have been used to investigate the thermal evolution of terrestrial planets. With the increase of computational power and improvement of numerical techniques, these models have become more complex, and simulations are now able to use a high resolution 3D spherical shell geometry and to account for st...

Solid body tides provide key information on the interior structure, evolution, and origin of the planetary bodies. Our Solar system harbours a very diverse population of planetary bodies, including those composed of rock, ice, gas, or a mixture of all. While a rich arsenal of geophysical methods has been developed over several years to infer knowle...

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 satisf...

Geophysical observations will provide key information about the inner structure of the planets and satellites and understanding the internal structure is a strong constraint on the bulk composition and thermal evolution of these bodies. Thus, geophysical observations are a key to uncovering the origin and evolution of the Moon. In this article, we...

We discuss the tidal deformation of Venus described by a viscoelastic rheological model and use the existing observables (e.g., the tidal Love number k2, the moment of inertia factor, and the crustal thickness) to constrain the interior structure and thermal evolution of the planet.

In this chapter, we focus on the long-term evolution of the atmosphere of Venus, and how it has been affected by interior/exterior cycles. The formation and evolution of Venus's atmosphere, leading to the present-day surface conditions, remain hotly debated and involve questions that tie into many disciplines. Here, we explore the mechanisms that s...

In this chapter, we focus on the long-term evolution of the atmosphere of Venus, and how it has been affected by interior/exterior cycles. The formation and evolution of Venus's atmosphere, leading to the present-day surface conditions, remain hotly debated and involve questions that tie into many disciplines. Here, we explore the mechanisms that s...

Geophysical observations will provide key information about the inner structure of the planets and satellites and understanding the internal structure is a strong constraint on the bulk composition and thermal evolution of these bodies. Thus, geophysical observations are a key to uncovering the origin and evolution of the Moon. In this article, we...

Recent studies of the data from the MESSENGER mission implied that volcanic activity on the surface of Mercury persisted for longer than expected. In order to explain this long-lasting activity on Mercury, studies advanced the presence of a thermal insulating layer enabling the mantle to be warmer for an extended period, here being the mega-regolit...

Here, we show the first results of coupling a grey atmosphere model (i.e., we assume that the absorption coefficients are constant and hence independent of frequency) considering only CO2 and H2O as greenhouse gases to the geodynamic code Gaia (Hüttig et al., 2013). The evolution of the atmospheric composition of a planet is largely determined by t...

Rifting and rises are prominent landscape features in the roughly triangular area characterized by the presence of three major rises (Atla, Beta and Themis) and two corona-dominated long chasmata (Hecate and Parga). The coronae population associated with these chasmata represents 35% of all Venusian coronae and 56% of coronae associated with fractu...

Over the past decades, global geodynamic models have been used to investigate the thermal evolution of terrestrial planets. With the increase of computational power and improvement of numerical techniques, these models have become more complex, and simulations are now able to use a high resolution 3D spherical shell geometry and to account for stro...

Bodily tides provide key information on the interior structure, evolution, and origin of the planetary bodies. Our Solar system harbors a very diverse population of planetary bodies, including those composed of rock, ice, gas, or a mixture of all. While a rich arsenal of geophysical methods has been developed over years to infer knowledge about the...

Planetary cores are key to understanding the conditions of planetary formation, composition and evolution. Recent seismic determination of the Martian core radius (e.g. Stähler et al, Science, 2021) supports the idea that Mars’ core contains a higher fraction of light elements than the Earth, and unlike Earth’s core it does not generate a global ma...

Constraining the thermal and compositional state of the mantle is crucial for deciphering the formation and evolution of Mars. As predicted by mineral physics, Mars’ deep mantle is demarcated by a seismic discontinuity with a depth that is sensitive to both mantle temperature and composition, and is ascribed to the pressure-induced phase transforma...

Surface waves had not been observed on any marsquake records during the first 3 years of seismic monitoring on Mars. We report the first detection of surface waves on Mars from two meteoroid impacts. The observed surface waves allow us to expand the current understanding of crustal structure on Mars beyond the crustal layering inferred beneath the...

We report the results of more than 2 years of monitoring the rotation of Mars with the RISE instrument on InSight. Small periodic variations of the spin axis orientation, called nutations, can be extracted from the Doppler data with enough precision to identify the influence of the Martian fluid core. For the first time for a planetary body other t...

Venus has long been of interest to humanity given its prominence in the night sky. With the development of the telescope and later multi-wavelength instrumentation and in-situ/orbiting spacecraft we have a detailed record of Venusian observations stretching back hundreds of years. This record of observations is only second to that of Mars and our o...

Martian basalts identified by rover in-situ analyses and the study of meteorites represent a direct link to the melting process in the planet’s interior and can be used to reconstruct the composition of the mantle and estimate its temperature. Experimentally calibrated numerical models are powerful tools to systematically search for the mantle comp...

Die Analyse von seismischen Wellen bildet die Grundlage für unser heutiges Verständnis vom Aufbau der Erde und des Mondes. Mehr als 100 Jahre nach den ersten Messungen der Dicke der Erdkruste und des Radius des Erdkerns ließen sich diese Größen erstmals auch für den Mars bestimmen, mithilfe des europäischen Seismometers SEIS der NASA-Mission InSigh...

Plain Language Summary The InSight mission operating on Mars is currently monitoring the planet's seismic activity. The recorded marsquakes can be used to obtain information on Mars' internal composition. However, the interpretation of these observations requires knowledge of the physical properties of the minerals expected to compose the Martian m...

Deltas have been long considered a constraining element to reconstruct the water level of an ancient ocean that may have once occupied the northern lowlands of Mars, and just recently this hypothesis started to be challenged. We investigate this hypothesis and present a global inventory of fan shaped features showing typical deltaic traits across t...

Single seismometer structure Because of the lack of direct seismic observations, the interior structure of Mars has been a mystery. Khan et al. , Knapmeyer-Endrun et al. , and Stähler et al. used recently detected marsquakes from the seismometer deployed during the InSight mission to map the interior of Mars (see the Perspective by Cottaar and Koel...

Single seismometer structure Because of the lack of direct seismic observations, the interior structure of Mars has been a mystery. Khan et al. , Knapmeyer-Endrun et al. , and Stähler et al. used recently detected marsquakes from the seismometer deployed during the InSight mission to map the interior of Mars (see the Perspective by Cottaar and Koel...

We use a large data set of 3D thermal evolution models to predict the distribution of present-day seismic velocities in the Martian interior. Our models show a difference between maximum and minimum S-wave velocity of up to 10% either below the crust, where thermal variations are largest, or at the depth of the olivine to wadsleyite phase transitio...

The icy moons of our Solar System, such as the Saturnian moon Enceladus and the Jovian moon Europa, are scientifically highly interesting targets for future space missions, since they are potentially hosting extraterrestrial life in their oceans below an icy crust. Moreover, the exploration of these icy moons will enhance our understanding of the e...

In Earth's deep continental subsurface, where groundwaters are often isolated for >106 to 109 years, energy released by radionuclides within rock produces oxidants and reductants that drive metabolisms of non-photosynthetic microorganisms. Similar processes could support past and present life in the martian subsurface. Sulfate-reducing microorganis...

The Martian mantle probably experienced an early global magma ocean stage. The crystallization and the fractionation and overturn of such a magma ocean likely led to the formation of a compositionally distinct layer at the bottom of the mantle. This layer would have been heavily enriched in iron and in heat-producing elements (HPE). The significant...