Multiplanetary systems in resonance offer a unique insights into planet formation and evolution. While resonant configurations, particularly among sub-Neptunes, probe dynamical and atmospheric interplay, their origins and survival rates remain debated. Theoretical models suggest primordial misalignment could disrupt resonance during formation; consequently, surviving resonant systems are...
V1298 Tau is a very young (20 ± 10 Myr) multi-planetary system that represents a benchmark laboratory for studying the early stages of planets' formation and evolution. Mainly due to the high levels of stellar magnetic activity, an undisputed description of the system has remained elusive so far, including the measurements of the planetary masses and densities, and the characterisation of its...
WASP-148 is an extrasolar system including two giant planets near the 4:1 mean-motion resonance. The inner one was first identified as a transiting candidate on a 8.8-d period from the SuperWASP photometric survey, then the SOPHIE spectrograph allowed it to be characterized, as well as the outer (P = 34.5 days) planet to be detected. Among other effects, the mutual gravitational interactions...
Super-Earths and sub-Neptunes are the most abundant type of planets in the Galaxy, and yet, they are absent from the Solar System. A possible reason for this absence is the giant planets. Indeed, their gravitational influence could have prevented the inward migration of enough disc material needed to form super-Earths. Dedicated RV surveys investigate this hypothesis, by searching for inner...
While several thousand exoplanets are now confirmed, the number of known transiting warm Jupiters ($10 ~\text{d} < \text{period} < 200 ~ \text{d}$) remains relatively small. These planets are generally believed to have formed outside the snowline and migrated to their current orbits. Because they are sufficiently distant from their host stars, they mitigate proximity effects and so offer...
Most detected transiting planets have orbits of a few tens of days, exposing them to intense stellar irradiation and interactions that significantly alter their properties. In contrast, colder planets with longer orbital periods are less affected, offering crucial insights into their formation and migration histories. In this talk, I report the detection and characterization of two...
The nearest rocky exoplanets are non-transiting, making their atmospheric characterization possible only through a combination of high spatial and spectroscopic separation of planetary and stellar light. Nearby rocky planets, particularly those in the habitable zone of their host stars, are prime targets for future missions such as LIFE and HWO to search for biosignatures. Most nearby stars...
Multiplanet systems in the exoplanet catalogues appear to be less well represented than Kepler transit statistics would suggest. Identification of exoplanet periodicities in radial velocity data via the sequential addition of Keplerian signals may lead to systematically biased multiplanet solutions. A Bayesian approach instead allows us to determine the optimal number of planet candidates by...
Despite the discovery of thousands of close-in sub-Neptune exoplanets in our galaxy to date, their exact nature continues to be a point of debate. The uncertainty in their compositions generally results from the inherent degeneracies in their mass-radius diagram. Recent work demonstrating that significant amounts of water can be produced endogenically by hydrogen magma-ocean interactions...
Close-in exoplanets are shaped by complex atmospheric and dynamical processes, to which exo-Neptunes appear to be particularly sensitive. While atmospheric erosion played a major role in forming the Neptunian "Desert" (a dearth of hot Neptunes at short orbital periods), it is not clear how far into the "Savanna" (a milder deficit of warm Neptunes at longer periods) this process is active and...
Atmospheric and dynamical processes are thought to play a major role in shaping the distribution of close-in exoplanets. A striking feature of such distribution is the Neptunian desert, a dearth of Neptunes on the shortest-period orbits. We aimed to define the boundaries of the Neptunian desert and study its transition into the savanna, a moderately populated region at larger orbital...
To date there have been already 724 binary star systems discovered, which inhabit at least one planet. Most studies that have investigated the late stage of terrestrial planet formation in binary stars considered planar configurations, which might be accurate for tight binary stars. However, for wide binary stars it is assumed, that the inclination between the two stars is randomly...
We present the results of a new and comprehensive approach to simulating the formation of terrestrial planets. Our approach begins with simulating the collisional growth of the first planetesimals and continues with resolving giant impacts using our state-of-the-art SPH-based model. We take into account all relevant physical processes including the dynamical friction due to the debris and...
Using a homogeneous analysis approach, we present a comprehensive study of close-in Neptune-sized planets. We compile a well-defined sample of TESS-observed planets, ranked based on their orbital period, radius, and the visual magnitude of their host stars. To ensure precise radial velocity measurements, we incorporate archival and new HARPS data, resulting in a final sample of 64 targets—46...
TRAPPIST-1 hosts seven planets. The period ratios of neighbouring pairs are close to the 8:5, 5:3, 3:2, 3:2, 4:3 and 3:2 ratios in increasing distance from the star. The Laplace angles associated with neighbouring triplets are observed to be librating, proving the resonant nature of the system. This compact, resonant configuration is a manifest sign of disk-driven migration; however, the...
Planetary systems in resonant chains are of particular interest both from a dynamical point of view and an observational point of view. In particular the three planet resonant angles are a valuable observable for transiting systems. Indeed, transit timing observations allow to measure the libration of these angles while in most cases the two planet angles cannot be observed. The final...
The formation of hot Jupiters remains an open question, with many proposed mechanisms well-suited to explain subsets of the observed population. Notably, the traditional high-eccentricity migration mechanism driven by a distant stellar companion is one of the oldest hot Jupiter formation channels, and it is often cited as the formation mechanism for hot Jupiters on high-obliquity orbits....
Two leading hypotheses of hot Jupiter formation are disk migration, where a Jupiter in the outer part of the disk and migrates inward due to gas drag, and high eccentricity migration (HEM), where a Jupiter is excited to an eccentric orbit by its stellar or planetary companion and subsequently circularizes close to the pericenter distance due to tidal dissipation in the planet. Measurement of...
The sub-Neptune population currently poses a conundrum. Are the smallest sub-Neptunes "gas dwarfs" (Earth-like cores surrounded by H/He envelopes) or "water worlds" (planets composed of ice and rock that migrated inward after forming beyond the snow line)? And if both populations exist, what are their distinguishing properties, and how do they depend on stellar type? Recent studies propose...
One of the primary and long-standing goals of the planetary science community is to understand planet formation and evolution. Most studies so far have been limited to planets around fully evolved stars, including those in the Solar System. However, models predict that the major phases of planetary evolution—such as formation (<3 Myr), disk migration (<5 Myr), evolutionary cooling (3–400 Myr),...
Recent advancements in exoplanet detection have led to over 5,700 confirmed detections. The planetary systems hosting these exoplanets exhibit remarkable diversity. The position of the innermost planet (i.e., the inner edge) in a planetary system provides important information about the relationship of the entire system to its host star properties, offering potentially valuable insights into...
Since the first exoplanets were found, astronomers have speculated about the possibility of detecting other minor bodies and effects associated with these worlds. Each of these promises to unlock new insights into exoplanets which would be otherwise inaccessible, such as their obliquity, internal structure and details of their history and evolution. In this talk, I will summarise what progress...
The PDS 70 system hosts the only two non-controversial protoplanets, offering a unique laboratory for planet formation studies. For instance, ALMA revealed around PDS 70 c the only circumplanetary disk ever detected. Also using ALMA data, we tentatively detected a trojan dust cloud sharing orbit with PDS 70 b. Remarkably, several authors have reported evidence for the presence of an additional...
Wide field surveys searching for transiting exoplanets also record and discover both known stellar variability and previously unknown phenomena. Deep and complex eclipses of otherwise unremarkable stars reveal eclipsing companions that have complex substructures. The ASAS-SN survey has now produced over a dozen complex eclipses that last from weeks to years, and we present our analyses of...
Roman Space Telescope (formerly the Wide-Field Infrared Survey Telescope or WFIRST) is a NASA infrared space telescope scheduled to launch by May 2027. Wilson et al. (2023) predicted that Roman will find between 60000 and 200000 transiting planets. Through the simulated photometric uncertainties, the detectability of exomoons with various configurations hosted by these transiting planets will...
In our Solar system all the giant planets have rings, but their origin and evolution are still uncertain. For exorings even less is known. I will discuss the importance of a large-scale systematic search for exorings and the steps I am taking towards achieving this. Once exoring candidates have been found then they need to be characterised. Therefore, I will also discuss the enigmatic ‘Dusty...
Population synthesis is very demanding in terms of computing power. These planetary systems can however provide access to correlations, as predicted in a given numerical framework, between the properties of planets in the same system. Using AI, we can leverage such correlations that, in return, can be used to guide and prioritize observational campaigns aiming at discovering certain types of...
In recent years, transiting circumstellar (or S-type) exoplanets in binary star systems have experienced a significant expansion, notably thanks to the successful TESS space mission. Binarity is expected to impact the formation and evolution of planets, particularly when the binary separation is smaller than a few hundred astronomical units, due to the truncation of the protoplanetary disk...
The characterization of exoplanetary masses is essential for understanding their composition and potential for atmospheric studies. The Tracking Hydrates In Refined Small Transiting Exo-Earths (THIRSTEE) programme aims to study the composition of sub-Neptunes planets. THIRSTEE is seacrhing the answers about the composition and formation of these planets around M dwarfs or Sun-like stars, their...
The search for exoplanets, planets orbiting stars outside our Solar System, has become a major focus in modern astronomy. One of the most effective techniques for detecting exoplanets is the radial velocity (RV) method, which tracks tiny shifts in a star’s RV caused by the gravitational pull of orbiting planets. The goal of this project is to compute planetary detection rates, by developing a...
Hot Jupiters are gas giant exoplanets that orbit their parent stars at very close distances, experiencing intense stellar irradiation. These extreme conditions lead to inflated radii, with most HJs exhibiting sizes larger than predicted by standard planetary cooling models. One possible mechanism contributing to this inflation is Ohmic heating, driven by the dissipation of currents generated...
Magnetic fields remain one of the least understood aspects of exoplanetary systems. A deeper understanding of planetary dynamos and the evolution of surface magnetic properties throughout a planet's lifetime is a key scientific purpose, with implications for planetary evolution, habitability, and atmospheric dynamics. This study models the evolution of magnetic fields generated by dynamo...
Due to the availability of high-performance computers and the data release from big-scale sky survey projects, the machine learning has been employed in many fields in astronomy. We have developed a numerical procedure of machine learning to search for transiting exoplanets from several survey data. Our procedure employs the convolutional neural network of deep learning techniques. In...
The search for and characterisation of extra-solar planets is at the forefront of scientific research. My research project aims to investigate astrometric possibilities for the identification of exoplanets, to get ready to fully exploit the forthcoming huge Gaia data release, foreseen to deliver thousands of new exoplanet candidates. In the anticipation of this dataset, astrometric...
The study of compact multi-planet systems provides us with unique insight into planet formation and evolution processes, particularly resonant systems that retain the architectures of early formation stages prior to destabilizing events. Within this framework, we will present a novel analysis of a two-planet system consisting of a confirmed planet and candidate companion in a possible...
The NASA Landolt mission is an astrophysics PIONEERS program small satellite that will provide significant improvement in the accuracy of photometric measurements of absolute stellar fluxes. This will be accomplished with a NIST-calibrated suite of single-mode fiber-fed laser beacons. The satellite will be placed in a near-geosynchronous orbit with a one-year primary mission with launch no...
PLATOSpec is a new echelle spectrograph with resolving power of 70,000, installed at former ESO 1.52-m telescope at La Silla. We would like to present new results from the science verification which include observing of Rossiter-Mclaughlin effect of selected systems and also stellar activity characterisation.
Young planets form great objects to study the early stages of planetary evolution. Due to the high activity of their host stars however, they are difficult to detect observationally. Using observations from the TESS satellite, we have compiled a list of candidate planets transiting young stars. We perform vetting through several steps such as checking background flux from nearby stars for...
When a star is born, a protoplanetary disk made of gas and dust surrounds the star. The disk can show gaps opened by different astrophysical mechanisms. The gap has a wall emitting radiation which contributes to the spectral energy distribution (SED) of the whole system (star, disk and planet) in the IR band. As these new-born stars are far away from us, it is difficult to know whether the gap...
Interiors of hot stars are able to conserve their angular momentum for longer time, keeping rotational velocities high for whole lifetime. If there is a planet orbiting such star, its orbit may change significantly over time. The planet may become highly eccentric, misaligned with respect to the rotational axis of the star or even undergo tidally-induced precession. Up to date, only 4...
New computational capabilities allow now to squeeze existing data to explore other parameter spaces of the exoplanet population. Despite the extensive amount of Kepler data available, systematic searches for co-orbital exoplanets (exotrojans) remain unexplored. In this work, as part of the TROY project, we present a new detection method based on the dynamical properties of these systems. We...
The V1298 Tau system is a young, four-planet system orbiting a ~20 Myr-old star, making it an ideal laboratory for studying the formation and early evolution of planetary systems. However, current estimates of the system’s orbital architecture remain poorly constrained. In particular, planetary eccentricities are largely unconstrained, and mass measurements have large uncertainties. Assuming...
My PhD research investigates the study of young planets from both observational and theoretical perspectives. These planets are undergoing various dynamic evolutionary processes, such as orbital migration, thermal contraction, and atmospheric loss, which provide valuable insights into the formation and early evolution of planetary systems. From the observational aspect, my research focuses on...
Variation in hot Jupiter occurrence rates across different stellar environments provides valuable insights into the formation and survival of these extreme planets. In this poster, I will present new results on the impact of the dynamical environment on hot Jupiter demographics and share preliminary findings from ongoing numerical studies exploring their formation in dense stellar systems.
Recent studies on the Solar System have shown that the ergodic assumption is not verified for the secular chaos, with quantities being almost conserved over planetary systems' lifetime. In particular, the total inclination angular momentum deficit (AMD), which describes the average mutual inclination of the orbits is almost conserved. This is an unexpected result since the variables are...
The European Space Agency’s (ESA’s) CHaracterising ExOPlanet Satellite (CHEOPS) is the first space mission dedicated to the search for exoplanetary transits through high-precision photometry of bright stars already known to host planets. This mission enables precise radius measurements for small exoplanets (super-Earths and sub-Neptunes), mass determinations for systems with transit timing...
Aprecise transit ephemeris serves as the premise for follow-up exoplanet observations. We compare TESS Object of Interest (TOI) transit timings of 262 hot Jupiters with the archival ephemeris and find 31 of them having TOI timing offsets, among which WASP-161b shows the most significant offset of −203.7 ±4.1 minutes. The median value of these offsets is 17.8 minutes, equivalent to 3.6σ. We...
The increasing discovery of extrasolar systems has made it necessary to study their stability. In this work, we present a generalization of the AMD-stability criterion defined by Laskar and Petit (2017), which defines a critical AMD-value below which close encounters are prevented and the system can be considered stable. This secular approach does not take into account mean-motion resonance...
Using the software REBOUND [1] we explore the possible stable configurations for the 2/1, 1/2 and 1/1 retrograde mean motion resonances in planetary systems with arbitrary masses through a Monte Carlo method. The simulations were divided in two different cases: 1) varying mass of one planet; 2) varying masses for both planets. The upper limit for the masses was set to 0.012 Msun as this is...
Binary stars are common and the number of systems with circumbinary planets is bound to increase with the advent of new missions like TESS, JWST. The indirect inference of planets around post-common envelope (CE) binaries has motivated investigations into their origin and survival in such violent environments. The potential existence of planets raises the question of whether the planets...
In the coming months, the first programmable liquid-crystal active coronagraph imager will begin operations at the DAO telescope (PLACID; Tandon et al. 2024). This instrument will potentially expand the capabilities for imaging planets and discs in complex environments, such as multiple star systems. This poster presents the framework of an observational program aimed at detecting planets and...
The Galactic Center contains a dense cluster of massive stars orbiting the central supermassive black hole, Sagittarius A$^\star$, collectively known as the S-cluster. While massive stars elsewhere in the Galaxy frequently reside in binary systems, the S-cluster appears to lack such companions. Among the S-cluster stars is S2, one of the most well-studied due to its close approach to...
The remarkable diversity of exoplanetary systems has challenged our understanding of planet formation and evolution. While many systems exhibit orderly, compact architectures, others appear dynamically excited or even sculpted by past instabilities. Interpreting this diversity requires connecting theoretical models of system evolution with emerging observational constraints.
In the first...
Recent works on three-planet mean motion resonances (MMRs) have highlighted their importance for understanding the details of the dynamics of planet formation and evolution. While the dynamics of two-planet MMRs are well understood and approximately described by a one-degree-of-freedom Hamiltonian, little is known of the exact dynamics of three-body resonances besides the cases of zeroth-order...
Observations with the TESS and Kepler have revealed that practically all close-in sub-Neptunes form in mean-motion resonant chains, most of which unravel on timescales of 100 Myr. Using a series of N-body integrations, we study how planetary collisions resulting from the destabilization of resonant chains produce the distribution of orbital periods observed among mature systems, focusing on...
The ejection of planets by the instability of planetary systems is a potential source of free-floating planets. We numerically simulate multi-planet systems to study the evolution process, the properties of surviving systems, and the statistics of ejected planets. For systems with only super-Earth planets, we find that the time (in units of the orbital period of the innermost planet) for the...
AU Mic is a highly active M dwarf star with an edge-on debris disk and two known transiting sub-Neptunes, with a possible third planetary companion. The two transiting planets exhibit significant transit-timing variations (TTVs). We conducted ultra-high-precision photometric observations with the CHaracterizing ExOPlanet Satellite (CHEOPS) in 2022 and 2023. We combined our new measurements...
I provide a standardized framework based on the second fundamental model of resonance to characterize the resonant state of planetary systems. This framework allows to easily distinguish systems that evolved through tidal dissipation from other systems.
The growing number of exoplanets detected over the past three decades has created a need for fast, reliable methods to study the long-term survival of planetary systems. Here, we investigate the challenging problem of the stability of compact three-planet systems, in which resonant and chaotic processes are intrinsically linked. Four completely different chaos indicators are tested on a data...
In nearly integrable Hamiltonian systems with n degrees of freedom, KAM theory guarantees, under suitable conditions, the existence of invariant tori of maximal dimension n , foliated by quasiperiodic orbits. In addition to these maximal tori, resonant tori of lower dimension p < n may also exist. These lower-dimensional tori play an important role in the study of extrasolar planetary systems....
Many transit-detected extrasolar systems harbor complex dynamical evolution governed by two-body resonances and/or chains of resonances. I will discuss how formation and dynamical studies can be useful to constrain the orbital parameters of these systems, which generally suffer from significant observational uncertainties. More precisely, I will show how i) periodic orbits can serve as...
Planetary migration models predict multiple planets captured into a chain of mean-motion resonances during the disk phase. Over a dozen systems have been observed in these configurations, nearly all close-in planets, with a lack of resonant chains for planets with orbital periods larger than ∼300 days. Dynamical studies often overlook the fact that stars do not evolve in isolation. In this...
Multi-planetary systems reveal diverse dynamical histories. Stellar obliquity is a key diagnostic of these histories, linking past dynamical interactions to migration pathways (e.g., quiescent disc vs. violent high-eccentricity). To measure the remaining dynamical violence of planetary systems, we introduce an obliquity-based NAMD (Normalized Angular Momentum Deficit), improving on the...
Young planetary systems are subjected to different dynamical effects that can influence their orbital structure over time. In systems with more than one planet, other planets can internally influence each other, e.g. via planet-planet scattering. In addition, external perturbing effects also need to be taken into account, as stars do not form by themselves but together with other stars in...
Extrasolar planetary systems commonly exhibit planets on eccentric orbits, with many systems located near or within mean-motion resonances, showcasing a wide diversity of orbital architectures. Such complex systems challenge traditional secular theories, which are limited to first-order approximations in planetary masses or rely on expansions in orbital elements—eccentricities, inclinations,...
More than a decade ago, several studies were published in order to investigate the nature of the periodic signal in radial velocity data for the 𝞶 Octantis binary system. The most likely explanation is the existence of a planet in a retrograde orbit with respect to the binary [1]. The ratio of the orbital periods between the potential planet and the binary is close to 5/2, so the possibility...
I will review the detection methods and properties of observed exoplanets in binary star systems and how those are helpful to tease out certain physical processes during planet formation.
The number of planets orbiting binary stars is increasing dramatically thanks to TESS and follow-up by direct imaging/Gaia. Understanding the origin and orbital architecture of these systems requires end-to-end planet formation models, which do not exist yet for planets orbiting only one of the two stars (S-type binaries). In this talk, I will introduce a new global planet formation model for...
In stellar multiple systems, orbits on the scale of ~10 to 100 au appear to suppress planet occurrence. However, some planetary systems do form and survive in close binaries, and the reasons why provide clues to important factors in successful planet formation. The Kepler sample remains the preeminent source of planetary demographics and, crucially, is also agnostic to stellar multiplicity. I...
It has long been argued that the occurrence rate of circumbinary planets (CBPs) should be comparable to that of planets around single stars (~10%). Yet, despite the favorable geometry of eclipsing binaries for transit detection and the modeled efficiency of planet formation in circumbinary natal disks, a set of only 14 transiting CBPs have been identified to date by Kepler and TESS, suggesting...
Of the 14 transiting planets that have been detected orbiting eclipsing binaries ('circumbinary planets'), none have been detected with stellar binary orbital periods shorter than 7 days, despite such binaries existing in abundance. The eccentricity-period data for stellar binaries indicates that short-period (< 7 day) binaries have had their orbits tidally circularized. We examine here to...
Of the thousands of known exoplanets, only fifteen are circumbinary, oribiting two stars instead of one. All of these systems have been detected via transit photometry, which requires a low mutual inclination for all three objects to eclipse. However, over a long time baseline a wide planetary-mass companion to a binary system will induce orbital precession, modulating the relative eclipse...
Of the types of planets orbiting binary stars, one particularly interesting category is planets with a very large mutual inclination with the inner binary, on a "polar" orbit. While polar circumbinary planets have eluded detection so far, highly misaligned and polar circumbinary gas and debris discs have been observed. Should these discs form planets it can be assumed that the corresponding...
Stellar multiplicity plays a crucial role in shaping planetary system architectures. While the influence of stellar companions has been widely explored in binary systems, planets in hierarchical triple systems remain largely underexplored. The complex gravitational interplay within these systems challenges planet formation models, influencing migration, altering orbital eccentricities, and...
In this work we present the latest developments in the problem of the stability of circumbinary planets and how to identify stable and unstable orbits in such systems. In this context, we carry out more than 3x10^8 numerical simulations of planets between the size of Mercury and the lower fusion boundary (13 Jupiter masses) which revolve around the center of mass of a stellar binary over long...
Numerical simulations of circum-stellar planetary orbits in binary star systems show that the eccentricity of such planets can vary due to the gravitational interaction with the secondary star. The evolution of the eccentricity depends on the architecture of the binary star-planet system. We have developed methods to localize these gravitational perturbations which display It is shown that...
An anomalous population of planets has recently been discovered in the previously barren Neptunian Desert. To understand these unusual planets it is important to recognise system and planetary properties that the Desert shares with more populous and well-studied types of exoplanets. In this work, we aim to discover whether a high stellar multiplicity rate is another of these features, shared...
Absolute astrometry and direct imaging enable the detection of (mostly) giant planets located beyond 5–10 AU – distances typically inaccessible to transit photometry and radial velocity methods. As such, they play a crucial role in probing the population of distant giant planets and testing models of planet formation. The youngest of these planets also provide unique opportunities to study...
Astrometric detections of exoplanets by missions like Gaia and JASMINE rely on measuring minute changes in the positions of stars - known as astrometric jitter - arising from the gravitational pull of the planetary companions. Another source of astrometric jitter is stellar magnetic activity which can interfere with the detection and characterization of Earth-mass planets through astrometric...
I wish to present a new tool called GaiaPMEX, introduced in two recent papers (Kiefer et al. 2024 a, b). It characterizes the mass and semi-major axis relative to the central star (sma) of any possible companion around any source observed with Gaia. It uses for the first time the value of RUWE published in the DR3 archives, and when available, combines it with the Gaia-Hipparcos proper motion...
HR8799 is a young multi-planet system that uniquely hosts four super-Jupiter planets and has been well-monitored through imaging and spectroscopy observations. This is the only directly imaged system for which we observe more than two exoplanets-- presenting a unique study of planet-planet interactions through astrometric measurements of high enough precision. Through the continued monitoring...
M-type stars, the most common in the universe, are a major focus for surveys because they are well-suited for detecting low-mass planets in the habitable zone. Despite their importance in the formation and evolution of low-mass planets, little is known about giant planets (GPs) in M star systems. Detecting long period GPs (with semi-major axis typically greater than 1 au) is difficult with...
The relation between the inner and outer regions of exoplanetary systems is still an open question, for example considering that recent studies are still presenting conflicting results on the relationship between short-period small planets and cold Jupiters. One of the key obstacles to solving this issue is that the most prolific detection techniques so far are strongly biased towards...
Hot- and cold-start planet formation models predict differing luminosities for the young, bright planets that direct imaging surveys are most sensitive to. However, precise mass estimates are required to distinguish between these models observationally. The presence of two directly imaged planets, PDS 70 b and c, in the PDS 70 protoplanetary disk provides us a unique opportunity for dynamical...
Analogues to the giant planets in our solar system are difficult to detect in the exoplanet context with our current observational methods. However, with new missions based on astrometry, these planets will become a prime population to study. The release of the Gaia DR4 catalogue in 2026, detecting ~1,000-10,000 giant planets at large orbital separations, will provide the first demographic...
With the ever-growing population of detected exoplanets, the startling variety in planetary configurations remains mostly unexplained. Studying planet formation in young stellar systems is a crucial step in order to truly understand this great diversity in observed exoplanets. To this end, the search for protoplanets is crucial; however, only two of them have been robustly confirmed so far,...
Blind direct imaging (DI) surveys carried-on with state-of-the-art high-contrast imaging instruments allow to detect just a low number of new planetary mass companions due to the paucity of such objects at the typical separations explored by such instruments. The possibility to couple DI with other techniques (e.g., astrometry and RV) allows to select targets with an high probability to host a...
The Keck Planet Imager and Characterizer (KPIC) is a high contrast imaging suite that feeds a high resolution spectrograph (1.9-2.5 microns, R~35,000) at the W.M. Keck Observatory. One target accessible with KPIC is GQ Lup B, a substellar companion with a detected circumplanetary disk, or CPD. Observations of the CPD suggest the presence of a cavity, possibly formed by an exo-satellite. Using...
Tidal forces between short-period planets and their host stars are extreme. These lead to the deformation of the planet and the shrinkage of the planet’s orbit.. Measuring the tidal deformation of the planet would allow us to estimate the second degree fluid Love number and gain insight into the planet's internal structure. Measuring the tidal decay timescale would allow us to estimate the...
Ultra-hot Jupiters (UHJs) orbit very close to their host stars, experiencing strong irradiation and tidal forces that markedly distinguish them of the Solar System giant planets. How the interiors of these planets change due to the extreme conditions is not yet fully understood since standard interior modelling techniques using mass and radius measurements lead to degenerate results. The...
The sub-Jovian exoplanet WASP-107b ranks among the best-characterized low-density worlds, featuring a Jupiter-like radius and a mass that lies firmly in the sub-Saturn range. Recently obtained JWST spectra reveal significant methane depletion in the atmosphere, indicating that WASP-107b’s envelope has both a high metallicity and an elevated internal heat flux. Together with a detected non-zero...
The inflated radii observed in hundreds of Hot Jupiters (HJs) represents a long-standing open issue, with Ohmic dissipation being one of the most promising mechanisms for a quantitative explanation. In this study, inspired by results from evolutionary models in the last decade, we specifically delve into the inferrance of the amount of electrical currents induced by the atmospheric winds....
Chemical evidence indicates that an appreciable fraction of Sun-like stars have engulfed rocky planets during their main-sequence lifetimes. We investigate whether the tidal evolution and destruction of ultra-short-period planets (USPs) can explain this phenomenon. We develop a simple parameterized model for the formation and engulfment of USPs in a population of MS stars. With this model, it...
Exoplanets in the hot Neptune desert, with their proximity to host stars and limited envelope masses, challenge our understanding of planetary evolution. Their survival despite expected significant atmospheric loss raises questions about their origins and the mechanisms shaping their evolution. To address these complexities, JADE (Joining Atmosphere and Dynamics for Exoplanets) was developed...
Very few planets have been discovered in the Neptunian desert, a region of period-radius parameter space encompassing Neptune-sized, short-period planets. The lack of planets in this region is explained by photoevaporation and high-eccentricity migration coupled with tidal disruption. However, since the launch of TESS a handful of planets have been discovered deep inside the Neptunian desert,...
The rich diversity of multi-planetary systems and their architectures is greatly contrasted by the uniformity exhibited within many of these systems. Previous studies have shown that compact Kepler systems often exhibit a peas-in-a-pod architecture: Planets in the same system tend to have similar sizes and masses and be regularly spaced in orbits with low eccentricities and small mutual...
The decay of short-lived radioisotopes (SLRs) is an important source of heating for early protoplanetary systems, and can affect planetesimal and subsequent planet formation through early thermal evolution, accelerated core-mantle differentiation and volatile outgassing. However, the mechanisms by which a stellar system becomes enriched with these SLRs to levels far above the galactic...
Resonances are a natural outcome of the migration of exoplanets. Consequently, they appear to be a crucial step in the formation of close-in sub-Neptunes. These exoplanets, with radii ranging from 1 to 4 Earth radii and orbital periods of less than 100 days, have been shown to exist around 30 to 50% of sun-like stars, based on early results from the HARPS spectrograph and the Kepler...
Transit Timing Variations are a powerful method for detecting and studying additional planets in exoplanetary systems. Hot Jupiters, massive gas giants orbiting very close to their stars, were once thought to exist in isolated orbits. However, recent discoveries of small nearby companions, have shown that these systems can be more complex. By analyzing TTVs, we can measure the masses, orbital...
We used PyDynamicaLC, a photodynamical model tailored for the analysis of the smallest- and lowest-TTV-amplitude- planets, to analyze Kepler’s multi-planet systems (Ofir+2025), where we were able to determine significant masses to 88 planets. We demonstrate consistency with literature results over 2 orders of magnitude in mass, and for the planets that already had literature mass estimations,...
Transit timing variations (TTVs) of hot Jupiters can reveal signatures of multiple physical processes, including apsidal precession, the Rømer effect, and notably, planetary migration. Hot Jupiters are believed to form at significant distances from their host stars and later migrate inward, a scenario that can be directly supported by TTV measurements. Detecting TTVs requires a long...
K2-19 hosts a pair of Neptune-like planets inside the 3:2 resonance, with previously reported eccentricities of 0.2 raising questions about conditions at the time of formation. Moreover, in spite of the system's resonant status both resonance angles circulate at these high eccentricities, contrary to common understanding. Tripling the observing baseline reveals the full resonant evolution of...
Recent TESS discoveries have revealed increasing number of exoplanetary systems exhibiting strong transit timing variations (TTVs), many of which consist of warm, Jovian-mass planet pairs near a 2:1 mean-motion resonance (MMR). I will present several peculiar TTV systems identified within the Warm gIaNts with tEss (WINE) collaboration, which systematically characterizes TESS transiting warm...
In multiple-planet systems, gravitational interactions of exoplanets could lead to transit timing variations (TTVs), whose amplitude becomes significantly enhanced when planets are near mean-motion resonances (MMRs), making them more easily detectable. In cases where both TTVs and radial velocity (RV) measurements are available, combined analysis can break degeneracies and provide robust...
Measuring transit timing variations allows us to study multi-planet systems, in particular probing planetary masses and dynamics. NGTS, with its high photometric precision, fast cadence and flexible scheduling, is very well suited to measuring transit timing variations . Here we present the suite of NGTS projects aimed at measuring transit timing variations over a range of targets and science...
We present the discovery and analysis of exceptionally large transit timing variations (TTVs) in the TOI-4504 exoplanetary system. Using data from NASA's Transiting Exoplanet Survey Satellite (TESS) and radial velocity measurements from FEROS, we identified TOI-4504 c as a warm Jupiter with a peak-to-node TTV amplitude of approximately 2 days, the largest such signal observed to date....
The Neptunian desert, a scarcity of Neptune-like planets in close orbit around their host stars, is an unexpected finding of the known exoplanet population. Large space-based surveys like TESS, together with ground-based follow-up, are identifying and confirming new transiting planet candidates in and near the desert. However, the targets that end up being followed form a heterogeneous and...
Understanding the demographics of close-in Neptune-sized planets is a key to exploring planet formation, particularly around the Neptunian desert. We performed a comprehensive search of TESS SPOC Full Frame Image light curves to identify transit signals. Candidate validation was conducted with our RAVEN pipeline, utilizing machine learning to identify false positives. The resulting sample...
The detection of exoplanets rely heavily on space-based transit surveys such as Kepler, TESS and PLATO. In these surveys, detecting and characterising small planets pose challenges due to their low signal-to-noise ratio (SNR). Standard methods, such as the Box least square (BLS) algorithm, exploit the periodic nature of orbits to enhance the SNR. But these methods are fundamentally limited...
The formation and evolution of planetary systems are linked to their host stellar environment. Here we employ a pebble accretion planet formation model to explore the correlation between planetary properties and stellar mass/metallicity. Our numerical results reproduce several main aspects of exoplanetary observations. First, we find that the occurrence rate of super-Earths ηSE follows an...
Exoplanets and smaller bodies have been detected orbiting different kind of stars. However, we do not know of any such objects in planetary nebulae, the short-lived stage of stellar evolution between the asymptotic giant branch and white dwarf phases. The planetary activity (destruction and formation) may be accompanied by dust clouds. Hence, we searched for dust occultation events in...
The GJ 9827 system hosts three planets in near-resonant orbits, smaller than two Earth radii. The two inner planets have an Earth-like composition, while the outer companion is a mini-Neptune with a volatile envelope. These features raise questions about the roles of in-situ formation and inward migration in shaping the system, which can be addressed by measuring the orbital architectures of...
Planets in compact multi-transiting systems tend to exhibit self-similarity with their neighbors, a phenomenon commonly called "peas-in-a-pod". Previous studies have identified that this self-similarity appears independently among super-Earths and sub-Neptunes orbiting the same star. In this study, we investigate whether the peas-in-a-pod phenomenon holds for planets in the radius gap between...
We consider the dynamic evolution of the compact four-planetary system K2-72. Star K2-72 is an M-type dwarf. The system contains three Earth-like planets and one super-Earth. We searched for low-order resonances within the uncertainty of determining the periods of the planets. We considered a few scenarios for the evolution of the K2-72 system over 100 Myr using the Posidonius software, which...
Evolution models of planetary systems find that resonant chains of planets often arise from their formation within protoplanetary disks. However, the occurrence of observed resonant chains, such as the notable TRAPPIST-1 system, is relatively low. This suggests that most of these chains become destabilized after the dissipation of the protoplanetary disk. Stellar tides, particularly the...
The orbital eccentricities of exoplanets quantify their current dynamical states and encode information about the predominant processes in their dynamical histories (e.g., the role of giant impacts vs. photoevaporation and core-powered mass loss in sculpting a system's dynamical state). Recent studies have demonstrated a relationship between orbital eccentricity and planet radius, showing...
