Romina Paula Di Sisto

• Phd
• Instituto de Astrofísica de La Plata. CONICET-UNLP

Context . The Hilda asteroids are located in the outer main belt (MB) in a stable 3:2 mean-motion resonance (MMR) with Jupiter, while the quasi-Hildas have similar orbits but are not directly under the effect of the MMR. Moreover, cometary activity has been detected in quasi-Hildas. Aims . In this study, we aim to investigate the collisional evolut...

The Hilda asteroids are located in the outer main belt in a stable 3:2 mean-motion resonance with Jupiter, while the quasi-Hildas (qH) have similar orbits but are not directly under the effect of the MMR. Moreover, cometary activity has been detected in qH. In this study, we investigate the collisional evolution of Hilda asteroids and apply it to s...

We present an updated ephemeris, and physical parameters, for the exoplanet WASP-77 A b. In this effort, we combine 64 ground- and space-based transit observations, 6 space-based eclipse observations, and 32 radial velocity observations to produce this target's most precise orbital solution to date aiding in the planning of James Webb Space Telesco...

We present an updated ephemeris and physical parameters for the exoplanet WASP-77 A b. In this effort, we combine 64 ground- and space-based transit observations, 6 space-based eclipse observations, and 32 radial velocity observations to produce the most precise orbital solution to date for this target, aiding in the planning of James Webb Space Te...

Aims. Ceres and Vesta are the two largest bodies in the main asteroid belt (MB) and have been extensively studied, particularly since the DAWN mission. Vesta is known to have an associated asteroid family, while the existence of a Ceres family is uncertain. This study investigates the fate of multi-kilometre fragments ejected from Ceres and Vesta d...

On December 14, 2020, southern South America experienced a total solar eclipse close to the solar noon. The path of totality, about 90 km wide, extended over the continental region from the Chilean west coast to the Argentine east coast, passing through the provinces of Neuquén, Río Negro and the extreme south of Buenos Aires. In order to study the...

Context. Impact crater counts on the Saturnian satellites are a key element for estimating their surface ages and placing constraints on their impactor population. The Cassini mission radar observations allowed crater counts to be made on the surface of Titan, revealing an unexpected scarcity of impact craters that show high levels of degradation....

Impact crater counts on the Saturnian satellites are a key element for estimating their surface ages and placing constraints on their impactor population. The Cassini mission radar observations allowed crater counts to be made on the surface of Titan, revealing an unexpected scarcity of impact craters that show high levels of degradation. Following...

We perform a study on the impacts on Ceres and Vesta. We aim to determine the size-frequency distribution (SFD) of impactors and to identify and quantify the contribution of each source region, as well as the craters produced and fragments ejected in these impact events. We used a multipart collisional evolution model of the MB called ACDC (Asteroi...

Context. Ceres and Vesta are the largest members of the main belt (MB). They were visited by the NASA Dawn spacecraft between 2011 and 2018, which provided a great sample of detailed observations of the surface of both bodies. Aims. We perform a study on the impacts on Ceres and Vesta. We aim to determine the size-frequency distribution (SFD) of im...

We developed a dedicated statistical test for a massive detection of spot- and facula-crossing anomalies in multiple exoplanetary transit lightcurves, based on the frequentist p-value thresholding. This test was used to augment our algorithmic pipeline for transit lightcurves analysis. It was applied to 1598 amateur and professional transit observa...

The current giant planet region is a transitional zone where transneptunian objects (TNOs) cross in their way to becoming Jupiter Family Comets. Their dynamical behavior is conditioned by the intrinsic dynamical features of TNOs and also by the encounters with the giant planets. We address the Giant Planet Crossing (GPC) population (those objects w...

The current giant planet region is a transitional zone where transneptunian objects (TNOs) cross in their way to becoming Jupiter Family Comets (JFCs). Their dynamical behavior is conditioned by the intrinsic dynamical features of TNOs and also by the encounters with the giant planets. We address the Giant Planet Crossing (GPC) population (those ob...

Aims. We developed a six-part collisional evolution model of the main asteroid belt (MB) and used it to study the contribution of the different regions of the MB to the near-earth asteroids (NEAs). Methods. We built a statistical code called ACDC that simulates the collisional evolution of the MB split into six regions (namely Inner, Middle, Pristi...

Aims. We developed a six-part collisional evolution model of the main asteroid belt (MB) and used it to study the contribution of the different regions of the MB to the near-Earth asteroids (NEAs). Methods. We built a statistical code called ACDC that simulates the collisional evolution of the MB split into six regions (namely Inner, Middle, Pristi...

We report follow-up observations of transiting exoplanets that have either large uncertainties (>10 minutes) in their transit times or have not been observed for over three years. A fully robotic ground-based telescope network, observations from citizen astronomers and data from TESS have been used to study eight planets, refining their ephemeris a...

We report follow-up observations of transiting exoplanets that have either large uncertainties (>10 minutes) in their transit times or have not been observed for over three years. A fully robotic ground-based telescope network, observations from citizen astronomers and data from TESS have been used to study eight planets, refining their ephemeris a...

From its discovery, the WASP-18 system with its massive transiting planet on a tight orbit was identified as a unique laboratory for studies on tidal planet-star interactions. In an analysis of Doppler data, which include five new measurements obtained with the HIRES/Keck-I instrument between 2012 and 2018, we show that the radial velocity signal o...

From its discovery, the WASP-18 system with its massive transiting planet on a tight orbit was identified as a unique laboratory for studies on tidal planet-star interactions. In an analysis of Doppler data, which include five new measurements obtained with the HIRES/Keck-I instrument between 2012 and 2018, we show that the radial velocity signal o...

The asteroid (2121) Sevastopol is a binary asteroid from the main belt. The duplicity of the asteroid was discovered based on photometric observations of mutual phenomena (eclipses and occultations) that were detected in its light curves (Higgins et al, 2010). We organized a photometrical observational campaign for the observations of mutual pheno...

We homogeneously analyse ∼3.2 × 105 photometric measurements for ∼1100 transit light curves belonging to 17 exoplanet hosts. The photometric data cover 16 years (2004–2019) and include amateur and professional observations. Old archival light curves were reprocessed using up-to-date exoplanetary parameters and empirically debiased limb-darkening mo...

We homogeneously analyse $\sim 3.2\times 10^5$ photometric measurements for $\sim 1100$ transit lightcurves belonging to $17$ exoplanet hosts. The photometric data cover $16$ years 2004--2019 and include amateur and professional observations. Old archival lightcurves were reprocessed using up-to-date exoplanetary parameters and empirically debiased...

Context. The small (≤135 km mean radius) satellites of Saturn are closely related to its rings and together they constitute a complex dynamical system where formation and destruction mechanisms compete against each other. The Cassini-Huygens mission provided high-resolution images of the surfaces of these satellites and therefore allowed for the ca...

In 1977, while Apple II and Atari computers were being sold, a tiny dot was observed in an inconvenient orbit. The minor body 1977 UB, to be named (2060) Chiron, with an orbit between Saturn and Uranus, became the first Centaur, a new class of minor bodies orbiting roughly between Jupiter and Neptune. The observed overabundance of short-period come...

The small ($\le$ 135 km mean radius) saturnian satellites are closely related to the rings and together they constitute a complex dynamical system where formation and destruction mechanisms compete against each other. We model the cratering process by Centaur objects on the small saturnian satellites, and compare our results with the observational...

Jupiter Trojan asteroids are located around L4 and L5 Lagrangian points on relatively stable orbits, in 1:1 MMR with Jupiter. However, not all of them lie in orbits that remain stable over the age of the Solar System. Unstable zones allow some Trojans to escape in time scales shorter than the Solar System age. This may contribute to populate other...

Jupiter Trojan asteroids are located around L4 and L5 Lagrangian points on relatively stable orbits, in 1:1 MMR with Jupiter. However, not all of them lie in orbits that remain stable over the age of the Solar System. Unstable zones allow some Trojans to escape in time scales shorter than the Solar System age. This may contribute to populate other...

Context. Recent studies have analyzed the dynamical evolution of outer small body populations under the effects of an eccentric inner massive perturber, which result from a planetary scattering event. These investigations suggest that such outer reservoirs are composed of particles on prograde and retrograde orbits, as well as particles whose orbit...

Recent studies have analyzed the dynamical evolution of outer small body populations under the effects of an eccentric inner massive perturber. Such outer reservoirs are composed of particles on prograde and retrograde orbits, as well as particles whose orbit flips from prograde to retrograde and back again showing a coupling between the inclinatio...

Aims. We analyze the dynamics of small body reservoirs under the effects of an eccentric inner giant planet resulting from a planetary scattering event around a 0.5M star. Methods. First, we used a semi-analytical model to define the properties of the protoplanetary disk that lead to the formation of three Jupiter-mass planets. Then, we carried out...

Binary asteroids are continuously being discovered in the main belt. Characterization of these system are very important to understand and constrain the origin and evolution of our Solar System. 2121 Sevastopol is a binary asteroid from the main belt. Its binary nature was discovered from photometric observations of mutual phenomena (eclipses and o...

Within the framework of this work, an observation campaign was organized, consisting of conducting photometric observations of mutual phenomena in the system of the given asteroid. Observations were conducted from June to October 2016. Observations made it possible to determine the masses, density, taxonometric class, as well as the preliminary orb...

We analyze the process of planetary scattering around M0-type stars. To do this, we carry out N-body simulations with three Jupiter-mass planets close to their instability limit together with an outer planetesimal disk. This paper focuses on the analysis of systems in which a single Jupiter-mass planet survives after the dynamical instability event...

The secular approximation of the hierarchical three body systems has been proven to be very useful in addressing many astrophysical systems, from planets, stars to black holes. In such a system two objects are on a tight orbit, and the tertiary is on a much wider orbit. Here we study the dynamics of a system by taking the tertiary mass to zero and...

The secular approximation of the hierarchical three body systems has been proven to be very useful in addressing many astrophysical systems, from planets, stars to black holes. In such a system two objects are on a tight orbit, and the tertiary is on a much wider orbit. Here we study the dynamics of a system by taking the tertiary mass to zero and...

We present a series of numerical integrations of observed and fictitious Jupiter Trojan asteroids, under the gravitational effects of the four outer planets, for time-spans comparable with the age of the Solar System. From these results we calculate the escape rate from each Lagrange point, and construct dynamical maps of "permanence" time in diffe...

We present a series of numerical integrations of observed and fictitious Jupiter Trojan asteroids, under the gravitational effects of the four outer planets, for time-spans comparable with the age of the Solar System. From these results we calculate the escape rate from each Lagrange point, and construct dynamical maps of “permanence” time in diffe...

WX Cen is one of a few compact binary supersoft X-ray sources (CBSS) in the Galaxy that is a possible Type Ia supernova (SN Ia) progenitor. The supersoft X-ray radiation is explained as hydrostatic nuclear burning on the surface of the white dwarf component that is accreting hydrogen from a stellar companion at a high rate. If the mass donor in thi...

Context. The Saturnian satellite system has been observed in detail by the Cassini-Huygens mission. These satellites present different surface features, including impact craters caused by small objects probably coming from the trans-Neptunian region. Aims: In this paper we calculate the production of craters on the mid-sized Saturnian satellites pr...

Hilda asteroids are objects that orbit the Sun at a distance where the orbital period is exactly 2/3 of the orbital period of Jupiter. Previous analytical and numerical studies have focused their attention to the great dynamical stability within the orbital region where the Hilda asteroids are found. However the group is indeed dispersing. In this...

Photometric observations of transits can be used to derive physical and orbital parameters of the system, like the planetary and stellar radius, orbital inclination and mean density of the star. Furthermore, monitoring possible periodic variations in transit timing of planets is important, since small changes can be caused by the presence of other...

We study the impactor flux and cratering on Ceres and Vesta caused by the collisional and dynamical evolution of the asteroid Main Belt. We develop a statistical code based on a well-tested model for the simultaneous evolution of the Main Belt and NEA size distributions. This code includes catastrophic collisions and noncollisional removal processe...

Phoebe is one of the irregular satellites of Saturn; the images taken by Cassini-Huygens spacecraft allowed us to analyze its surface and the craters on it. We study the craters on Phoebe produced by Centaur objects from the Scattered Disk (SD) and plutinos escaped from the 3:2 mean motion resonance with Neptune and compare our results with the obs...

We present a study of the dynamical evolution of plutinos recently escaped from the resonance through numerical simulations. It was shown in previous works the existence of weakly chaotic orbits in the plutino population that diffuse very slowly finally diving into a strong chaotic region. These orbits correspond to long-term plutino escapers and t...

We present results from numerical simulations of a Jupiter family comet (JFC) population (orbital periods P < 20 yr and Tisserand parameters in the range 2 < T < 3.1) originated in the Scattered Disk and transferred to the Jupiter's zone through gravitational interactions with the Jovian planets. We shall call ‘non-JFCs’ those comets coming from th...

We study the impactor flux and cratering on Pluto and Charon due to the collisional evolution of Plutinos. Plutinos are those trans-Neptunian objects located at 39.5 AU, in the 3:2 mean motion resonance with Neptune. To do this, we develop a statistical code that includes catastrophic collisions and cratering events, and takes into account the stab...

It was shown in previous works the existence of weakly chaotic orbits in the plutino population that diffuse very slowly. These orbits correspond to long-term plutino escapers and then represent the plutinos that are escaping from the resonance at present. In this paper we perform numerical simulations in order to explore the dynamical evolution of...

We study the Jupiter family comet (JFC) population assumed to come from the Scattered Disk and transferred to the Jupiter’s zone through gravitational interactions with the Jovian planets. We shall define as JFCs those with orbital periods and Tisserand parameters in the range 2<T≲3.1, while those comets coming from the same source, but that do not...

In this work, we study the impactor flux on Pluto and Charon due to the collisional evolution of Plutinos.To do this, we develop a statistical code that includes catastrophic collisions and cratering events, and takes into account the stability and instability zones of the 3:2 mean motion resonance with Neptune. Our results suggest that if 1 Pluto-...

Hilda asteroids are objects that orbit the Sun at a distance where the orbital period is exactly 2/3 of the orbital period of Jupiter. Previous analytical and numerical studies have focused their attention to the great dynamical stability within the orbital region where the Hilda asteroids are found. However the group is indeed dispersing. In this...

Aims: In this paper, we analyze the collisional and dynamical evolution of the population of Plutinos. Methods: To do this, we test different collisional parameters and include a dynamical treatment that takes into account the stability and instability zones of the 3:2 mean motion resonance with Neptune. This procedure allows us to estimate the siz...

Se ha realizado una base de datos con las placas fotográficas obtenidas con el Astrográfico del Observatorio de La Plata. Se han clasificado un total de 3000 placas obtenidas para asteroides y cometas. El acceso a la base de datos se hará por FTP y la misma contendrá la siguiente información: fecha y tiempo de exposición, coordenadas del centro de...

We analyze the Centaur population as a group of objects with perihelion distances (q) of less than 30 AU and heliocentric distances outside the orbit of Jupiter, formed by objects entering this region from the Scattered Disk (SD). We perform a numerical integration of 95 real Scattered Disk Objects (SDOs) extracted from the Minor Planet Center data...

The orbit of the outermost Saturn's irregular moon, Phoebe, suggests that it was captured by Saturn rather than formed in situ. The Cassini-Huygens mission results allowed to find that Phoebe's composition is similar to that derived for the outer solar system bodies and very different from the composition of the Saturn regular satellites. In this...

Hilda asteroids and comets are similar from the compositional point of view. The D-taxonomic class prevailing among Hildas has all the characteristics found in cometary spectra. Jupiter Family Comets (JFCs) coming from the trans-neptunian region are under the gravitational control of Jupiter, making them a dynamically unstable population with a mea...

We study the dynamical evolution of the Hilda group of asteroids trough numerical methods, performing also a collisional pseudo-evolution of the present population, in order to calculate the rate of evaporation and its contribution to the cratering history of the Galilean satellites. If the present population of small asteroids in the Hilda's regio...

An ideal mixture of parahydrogen (with nuclear spin K=0) and orthohydrogen (with K=1), in statistical weights 1/4 and 3/4, respectively, is used as a test ground for the existence of nonextensivity in chemical physics. We report on a new bound on the nonextensivity parameter q−1 that characterizes generalized thermostatistics à la Tsallis. This bou...

The most plausible sources of the terrestrial water are found in the main external asteroid belt, the giant planetary region and in the Kuiper belt, because of its great presence of ices. However, the timing of earth planets's formation (108 years) marks an inferior limit for the dynamical lifetime of the objects of interest since the previous mega...

The recent proposal by Tsallis of a generalized thermostatistics devised to treat systems endowed with long-range interactions, long-range memory effects, or a fractal-like relevant phase space, has raised interesting and profound issues concerning the properties of general thermostatistical formalisms. In the present paper we identify families of...

In 1996 a recopilation and clasification of all existent photographic plates in La Plata Observatory has been made. This clasification has allowed to build a computer database for 2031 plates of asteroids and for 156 of comets taken between the years 1948 and 1986. All the existent material contained in the photographic plates of La Plata Observato...

The collection of photographic plates at the La Plata Observatory contains a large number of plates taken with the Astrographic Telescope of aperture 343 mm and focal lenght 3.42 m. The data from direct-photographic observations have been organized as a computer readable-catalogue of plates since 1948. We have available 2030 plates of asteroids and...

El Observatorio de La Plata cuenta con un gran número de placas de asteroides y cometas obtenidas con el telescopio astrográfico, que cubren gran parte del cielo del hemisferio sur. En 1996 se recopilaron y clasificaron 2187 placas (Beca para estudiantes de la AAA 1996) de las cuales 2031 corresponden a asteroides. Los datos de cada placa se volcar...

The distinction between asteroids and comets, is based in their observational qualities rather than in their orbital characteristics. Comets show activity when they reach the interior Solar System. Asteroids from the outer Belt, may have compound of the same volatile material, dust and organic molecules than comets, but they didn't approach enough...