Katherine Villavicencio-Valero’s research while affiliated with University of Chieti-Pescara and other places

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Publications (3)


Figure 3. Surface temperature evolution for the dark and bright hemispheres of Iapetus. The temperature for the leading side, represented with a blue line, starts at 90 K and evolves until almost 130 K during the model time. The trailing side, depicted with a red line, starts at 130 K and grows to 147 K. There is a substantial increment in temperature for both sides, but the increment in the leading side is greater, possibly due to the low albedo of 0.04 and its composition.
Influence of the Surface Temperature Evolution over Organic and Inorganic Compounds on Iapetus
  • Article
  • Full-text available

September 2023

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26 Reads

Universe

Katherine Villavicencio-Valero

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Emilio Ramírez-Juidias

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Antonio Madueño-Luna

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[...]

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Miguel Calixto López-Gordillo

In this manuscript, there were performed simulations of the evolution of the surface temperature for each of the two hemispheres of Iapetus. This icy moon of Saturn shows the most differentiated albedo dichotomy of the Solar System. The dark leading side has a lower albedo than the bright trailing side. Spectral data on the visible light reveal the existence of two types of materials on the surface. The darkening in the leading side is thought to be due to the presence of organic material and carbonaceous compounds on the surface, while the trailing side is covered by water ice due to migration processes from the dark side. On airless bodies like Iapetus, the surface escape speed is greater than the speed of water molecules, resulting in the retention of a H2O atmosphere that allows some species to diffuse through it. Results showed a slow yet steady increment of temperatures for both sides, with a steeper slope for the dark hemisphere. It was also simulated how much energy can be accumulated on both sides and the consequences of that. Finally, we calculated the diffusion coefficients for ammonia, methane, and water ice. The results allowed us to infer how these compounds could evolve over time.

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Figure 2. The outgoing thermal radiation and the incoming stellar radiation are displayed for the dark and bright hemispheres in Figure 2a and 2b respectively. In the leading hemisphere, the outgoing radiation is constant at 2.8 W m -2 , while in the trailing side it remains constant at 26 W m -2 . This discrepancy could be a consequence of the different values of their albedos. Low temperatures and high albedo in the bright side do not allow for the retaining of flux radiation in the atmosphere, that is why, the outgoing thermal radiation is higher. In both sides, the incoming radiation is weak, with a roughly value of 0.2 W m -2 .
Influence of the Surface Temperature Evolution over Organic and Inorganic Compounds on Iapetus

June 2023

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23 Reads

Iapetus, a Saturn moon, shows the most differentiated albedo dichotomy of the Solar System. The dark leading side has a lower albedo than the bright trailing side. Spectral data on the visible light reveal the existence of two types of materials on the surface. The darkening in the leading side is thought to be originated by the presence of organic material and carbonaceous compounds on surface, while the trailing side is covered by water ice due to migration processes from the dark side. On airless bodies like Iapetus, the surface escape speed is greater than the speed of water molecules, resulting in the retention of a H2O atmosphere that allows some species to get diffused through it. Here, there were performed simulations of the evolution of the surface temperature for each of the two hemispheres of Iapetus. The results showed a slow yet steady increment of temperatures for both sides, with a steeper slope for the dark hemisphere. It was also simulated how much energy budget can be accumulated in both sides and its consequences. Finally, we calculated the diffusion coefficients for ammonia, methane, and water ice. The results let us infer how these compounds could evolve over time.


Sedimentation and Proposed Algorithms to Detect the Possible Existence of Vegetation and Humidity in the Landing Area of the Mars Exploration Rover-B (Opportunity)

May 2021

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105 Reads

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2 Citations

Opportunity was launched in 2004 and has been providing interesting data from Mars till 2018. Meridiani Planum was the landing site for the robot. This crater has numerous rock outcrops, which are considered a valuable geological resource that contains keys to the Martian past. In this work, several algorithms have been developed for detecting the possible presence of humidity and vegetation on Mars through the images sent by the Mars Exploration Rover - B Opportunity and by the Viking Orbiter between 1976 and 1980. For this, it was carried out a sedimentary simulation of the study area, as well as an analysis of all the images from the spectral signatures extracted. The results show the existence of three types of water on the surface, as well as concentrations of Neoxanthin, also on landing area surface, that suggest the possible existence of microalgae.

Citations (1)


... While various field studies have been conducted to examine ecosystem processes and their implications for mitigating future global land degradation [12] or on how to evaluate a population's high flooding vulnerability due to climate change in wetland ecosystems [13], it remains difficult to generalize findings from patch-scale research to other regions. In the field of geomatics, while satellite platforms can help us address this issue, light detection and ranging (LIDAR) data have a clear benefit, as they precisely capture marshes' physical characteristics, which traditional contour mapping often fails to achieve [14,15]. Consequently, LIDAR data provide the crucial spatial information needed for a detailed marsh-scale analysis of the relationships between climatic variables and soil erosion. ...

Reference:

Use of Geomatic Techniques to Determine the Influence of Climate Change on the Evolution of the Doñana Salt Marshes’ Flooded Area between 2009 and 2020
Sedimentation and Proposed Algorithms to Detect the Possible Existence of Vegetation and Humidity in the Landing Area of the Mars Exploration Rover-B (Opportunity)