Resumo:

It has been considered that the molecular clouds, essentially composed of hydrogen, helium and dust particles, collapse giving rise to a protostar that leaves as a remnant a circumstellar disk where planets are formed; which sweep their orbit, generating the rings observed by ALMA and DSHARP. This study shows that the formation of the protostar and rings is an effect of the random encounter of particles in space, which together with gravity leads to stellar and planetary formation. Using this paradigm, a relation is obtained to determine the interplanetary distance (e.g., Solar System), then the density function is established for a transition ring (e.g., DoAr 44), and an extension is made to describe the rings observed in protoplanetary systems (e.g., Hl-Tauri). Consequently, the obtained density function is the initial condition to computationally simulate a protostar or a protoplanetary disk.

Resumo:

Recently, it has been reported the discovery of a dense ring around the trans-Neptunian object 50000 Quaoar. The ring particles seem to be very close to the 6/1 mean motion resonance with Weywot, the only known satellite in the system. In this work we investigate the dynamical environment in the close vicinity of the 6/1 orbital resonance in the context of the restricted three body problem. We aim to analyze whether, in view of observational constraints, the ring could be effectively evolving in resonant motion with the satellite. Through the technique of dynamical maps we identify and characterize the 6/1 mean motion resonance, finding that the main location of the resonance deviates by only $29$ km from the central part of the ring. This difference lies within the 3$\sigma$ confidence level, considering the uncertainties in the observational parameters. We also show that the Weywot's eccentricity plays a significant role in the dynamical structure of the 6/1 resonance. The results show that the resonance width is smaller than the estimated ring's width. Under assumption of a ring with eccentricity smaller than 0.05, clumping of test particles appears at the position of the different resonant multiplets, considering the nominal value of Weywot's eccentricity. This is in agreement with observations, which indicate that the estimated resonance width ($\leq$ 10 km) is comparable with the narrow and dense arc of material within Quaoar's ring. Our results may be an indicative that the 6/1 resonance resonance plays a key role in confining the arc ring.

Resumo:

The atmosphere of Mars has been the subject of study in numerous scientific investigations to understand its complex atmospheric phenomena. In this research work, we have explored the existence of an interesting relationship between the periodic oscillations of H$_2$O concentration in the Martian atmosphere and the Pectinton solar flux index in the 10.7 cm band, around the characteristic solar activity period of 11 years. To investigate this relationship, the H$_2$O abundance data package provided by SPICAM from Mars Express was analyzed, spanning the time window from 2004 to 2018. These data were compared with solar flux records obtained from the NOAA database. The analysis was carried out by calculating the Lomb-Scargle periodogram for both signals. Although this method is commonly used in the study of star light curves, its application to planetary atmospheres has shown promise, providing results consistent with models that describe periodic variations in the atmosphere, such as seasonal changes. To validate the effectiveness of this method, it was tested against data sets of abundances of different chemical species at various heights in the Earth's atmosphere. These data were obtained from the empirical model NRLMSISE-00 and covered a wide range of years between 1961 and 2021. The results obtained from both the terrestrial model and the data derived from SPICAM detections supported the usefulness of the method for the study of oscillatory phenomena. of long periods, such as days, months and years, that can occur in the atmosphere of a planet, or in its possible relationship with other factors. This research work brings new insights into the atmospheric dynamics of Mars and its connection to the solar cycle, which could have significant implications for the study of other celestial bodies and for a deeper understanding of them. climatic processes in planetary environments.

Resumo:

Transit-timing variation (TTV) is a powerful technique to infer the existence of previously undetected planets by measuring the non-periodicity of the transit times resulting from the gravitational perturbations from other planets. The TTVs also provide a way of inferring masses and eccentricities in multiple transiting systems, in particular for systems near MMRs which are subject to large TTV signals. The amplitude and period of the TTVs strongly depend on the distance to the exact commensurability and the eccentricities of the planets. These quantities are often shaped during the phase of planet-disk interactions and, to a greater extent, modified during the long-term evolution of the system. In particular, for close-in planets the tides raised by the host star provide a source of dissipation on very long timescales, placing the planets further away from the commensurabilities. In this work, we will discuss how the tidal interactions play an important role in shaping the period ratios in planetary systems with resonant chains, highlighting that the trend observed in the resonance offsets are due to the 3-planet resonant dynamics. Moreover, we will show how the tidal interactions between the planets and the central star can impact the TTVs and therefore how the TTVs could serve as a means to put constraints on the tidal history of the planetary systems. The study will focus on the Kepler-80 system, which harbor a resonant chain of four close-in planets.

Resumo:

Jupiter-like planets are the key to understanding Earth-like planets. Their presence can disrupt the orbits of inner habitable worlds, or deliver life-sustaining water. While the search for Earth-like planets orbiting nearby stars garners the most attention, it is critically important to understand the presence and properties of giant planets in those systems. In the next decade, three space missions will provide unprecedented new opportunities for understanding the nature of these Jupiter analogs: Gaia, the James Webb Space Telescope, and the Nancy Grace Roman Space Telescope. We aim to take advantage of the multi-messenger synergy of these observatories, in combination with Australia's unique Minerva-Australis telescope array, to obtain a complete picture of the nearest extrasolar planetary systems. Dozens of cold giant planets are known from radial-velocity planet searches. But their true masses remain unknown due to the limitations of the technique. In Data Releases 4 and 5 (2024/26) the Gaia space astrometry mission will deliver the critical measurements of 3-dimensional architecture for these planetary systems. Combined with the minimum masses obtained from radial velocities, we will obtain the true masses of those planets. Our Minerva-Australis observatory is fully dedicated to radial-velocity measurements; it is the only such facility in the Southern hemisphere. We will use these data to better characterise nearby Jupiter analogs for which true masses and orbital inclinations can be derived with forthcoming Gaia data. With detailed knowledge of the properties of those giant planets, we can model the extent to which those planets deliver water to inner Earth analogs via comet impacts. These Jupiter analogs will also be prime targets for direct imaging by JWST and Roman.

Resumo:

Co-orbital orbital dynamics is really important to understand some aspects of small body populations in our Solar System. The most studied case in the literature are Jupiter Trojans. Not all planets have known coorbitals. For example, Venus, Earth and Mars have confirmed ones but their stability has been a matter of some debate in the literature. There are several co-orbital motion types: tadpoles, horseshoes and quasi satellites. Remember that in the classic planar circular case we only have two tadpoles which librate around +-60°, those are the ones called Trojans and are located in usually called L4 and L5 equilibrium points. It is important to notice that when the eccentricity or inclination of the secondary body grows those points change their position. This semi-analytical approach can be used to study any resonance such as 1:1 in this case. It provides a numerically integrated Hamiltonian and equilibrium points, as well as resonance widths and periods of librations. The advantage of using this theory is that we do not have restrictions in eccentricity nor inclination except for almost circular orbits where the hypothesis of the model fails. Our objective is to test the model under extreme conditions. Using it, we have mapped the location of equilibrium points for high eccentric and/or inclination orbits and searched for possible known asteroids in the NASA Horizons catalog that match this type of orbits. Furthermore, some problems can be modeled with this work such as pollution in white dwarf spectra. It has been proposed that post main sequence evolved small body population falling into the star due to resonant perturbations in high eccentric orbits could explain this. Also, we can apply this theory to study systems with two co-orbital planets such as the recent evidence for exoplanet system PDS 70 could indicate.

Resumo:

We study the secular evolution of two planets in mutual deep mean motion resonance (MMR) in the planar elliptic three body problem framework. We do not consider any restriction neither in the inner planet's eccentricity $e_1$ nor in the outer planet's eccentricity $e_2$. The methodology used is based on a semi-analytical model that consists on calculating the averaged resonant disturbing function numerically, assuming for this that all the orbital elements (except for the mean longitudes) of both planets are constant in the resonant time scale. In order to obtain the secular evolution inside the MMR, we make use of the adiabatic invariance principle, assuming a zero-amplitude resonant libration. We construct two phase portraits, named $\mathcal{H}_1$ and $\mathcal{H}_2$ surfaces, in the three-dimensional spaces $(e_1, \Delta\varpi, \sigma)$ and $(e_2, \Delta\varpi, \sigma)$ where $\Delta\varpi$ is the difference between the planet's longitude of perihelia and $\sigma$ the critical angle. These surfaces, which are related through the angular moment conservation (or through the AMD conservation), allow us to find the apsidal co-rotation resonances (ACRs) and to predict the secular evolution of $e_1$, $e_2$, $\Delta\varpi$ and $\sigma$ (libration center). While studying the 1:1, 2:1, 3:1 and 3:2 MMR we found that large excursions in eccentricity can exist in some particular cases. We corroborate the secular variations of $e_1$, $e_2$, $\Delta\varpi$ and $\sigma$ predicted by the model comparing them with numerical integration of the exact equations of motion. Finally, the model is applied to study the exoplanet systems HD 73526, HD 31527 and K2-19, finding interesting features in each secular evolution.

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Discoveries of extrasolar planetary systems have shown that the configuration of our Solar System is an exception to the rule given the number of systems with high relative inclinations, large eccentricities and high mass planets in orbits with periods of hours. Due to these peculiar characteristics, our goal is to understand the processes that led planetary systems to acquire such characteristics, through mutual gravitational interaction and with the proto-planetary disk. To verify the quality of the observational data and the stability of the planetary systems in periods of at least 1Myr, we use the concepts of Hill Stability (Marchal \\& Bozis (1982) and Gladman (1993)) that consider the configuration of the systems in terms of total energy and orbital angular momentum; to evaluate their secular movements we work with the construction of Representative Plans that bring with them information of the long-period behavior of the system, based only on the mass ratio of the planets and the ratio of their semi-major axes; To analyze the temporal evolution, we use the theory of semi-analytical perturbation (Michtchenko \\& Malhotra, 2004) that allows us to explore systems of high eccentricities by not working with series expansions of the Disturbing Function. We work with models that simulate the process of planetary migration (Michtchenko \\& Rodríguez, 2011), which change the orbital elements in a forced way, seeking to relate the migration trajectories with known processes, interaction of the planet with proto planetary disk, accretion of matter and tidal effects. Using the stability criteria, we selected some planetary systems to start the analysis and, after verifying their secular behavior, we started the simulations of migratory processes to understand through which configurations the system passed until arriving in the current state, considering only the variation of the total energy of the system and the orbital angular momentum.

Resumo:

One of the challenges in planetary formation models is, including the main physical phenomena in that process, to explain the diverse architectures of planetary systems observed to date. The modelling of collisions and planetesimal fragmentation is key to reproducing planetary formation and evolution correctly. Depending on the particle sizes and impact velocities, these collisions may result in different outcomes, such as growth, rebound, erosion, mass transfer, fragmentation, craterization, compaction, or grinding. Our previous works show that the inclusion of a detailed model of planetesimal fragmentation, considering different compositions and relative velocities of planetesimals, may inhibit or favour the formation of giant planet cores, drastically changing the final planetary system architectures. However, in the planetary formation global models, the detailed modelling of these processes is extremely expensive from a computational point of view. Generally, these models include the planetesimal fragmentation process locally. In this work, we study and compare a local approximation of this process that simplifies the phenomenon numerically, significantly reducing the computing time required for our simulations. We compare these results to our detailed model of planetesimal fragmentation applied to giant planet formation and contrast it with other local approximations in the literature to determine its validity. Currently, the large amount of observational data provides us with statistical properties of the exoplanet population and constraints for planetary formation models. Population synthesis models allow us to link these properties with the physical processes that take part in the planetary formation process. For the future, our aim is to conduct a population synthesis study that includes planetesimal fragmentation into PLANETALP, our global model of planet formation.

Resumo:

The fundamental question of how the gas and solids in protoplanetary disks evolve with time remains unanswered. However, the ongoing ALMA Large Program AGE-PRO (“ALMA survey of Gas Evolution in PROtoplanetary disks”) was designed to answer this question for the gas component. AGE-PRO will trace the evolution of gas disk mass and size throughout the lifetime of disks, using a well-defined sample of 30 disks between 0.1 and 10 million years old. By studying a large sample of disks at different ages, AGE-PRO will be able to identify the key factors that drive the evolution of gas disks, and to better understand how these disks ultimately give rise to planets. Here I present the preliminary analysis on the Upper Scorpius and Ophiuchus, the oldest and the youngest region in our sample, respectively. For Upper Scorpius we have imaged gas and continuum emission, and generated disk-integrated line fluxes and radial intensity profiles for all lines and for the continuum, in all 10 disks selected. Additionally, we have analyzed the young Ophiuchus star forming region to examine the nature of the gas rotation with CO isotopologues. We are deriving rotational profiles from the PV diagrams and the size of Keplerian disks for Class I/FS sources. These results will establish a foundation for understanding the global structure and evolution of protoplanetary disks. This will provide essential context for future in-depth studies of planet formation processes in disks.