Judit Szulágyi

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Szulágyi

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Judit

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0000-0001-8442-4043

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Publications 1 - 10 of 44

An exomoon survey of 70 cool giant exoplanets and the new candidate Kepler-1708 b-i
Kipping, David; Bryson, Steve; Burke, Chris; et al. (2022)
Nature Astronomy
Exomoons represent a crucial missing puzzle piece in our efforts to understand extrasolar planetary systems. To address this deficiency, we here describe an exomoon survey of 70 cool, giant transiting exoplanet candidates found by Kepler. We identify only one exhibiting a moon-like signal that passes a battery of vetting tests: Kepler-1708 b. We show that Kepler-1708 b is a statistically validated Jupiter-sized planet orbiting a Sun-like quiescent star at 1.6 au. The signal of the exomoon candidate, Kepler-1708 b-i, is a 4.8σ effect and is persistent across different instrumental detrending methods, with a 1% false-positive probability via injection-recovery. Kepler-1708 b-i is ~2.6 Earth radii and is located in an approximately coplanar orbit at ~12 planetary radii from its ~1.6 au Jupiter-sized host. Future observations will be necessary to validate or reject the candidate.
Effects of the Planetary Temperature on the Circumplanetary Disk and on the Gap
Szulágyi, Judit (2017)
The Astrophysical Journal
In Situ Formation of Icy Moons of Uranus and Neptune
Szulágyi, Judit; Cilibrasi, Marco; Mayer, Lucio (2018)
The Astrophysical Journal Letters
In-depth direct imaging and spectroscopic characterization of the young Solar System analog HD 95086
Desgrange, Célia; Chauvin, Gaël; Christiaens, Valentin; et al. (2022)
Astronomy & Astrophysics
Context. HD 95086 is a young nearby Solar System analog hosting a giant exoplanet orbiting at 57 au from the star between an inner and outer debris belt. The existence of additional planets has been suggested as the mechanism that maintains the broad cavity between the two belts. Aims. We present a dedicated monitoring of HD 95086 with the VLT/SPHERE instrument to refine the orbital and atmospheric properties of HD 95086 b, and to search for additional planets in this system. Methods. SPHERE observations, spread over ten epochs from 2015 to 2019 and including five new datasets, were used. Combined with archival observations, from VLT/NaCo (2012-2013) and Gemini/GPI (2013-2016), the extended set of astrometric measurements allowed us to refine the orbital properties of HD 95086 b. We also investigated the spectral properties and the presence of a circumplanetary disk around HD 95086 b by using the special fitting tool exploring the diversity of several atmospheric models. In addition, we improved our detection limits in order to search for a putative planet c via the K-Stacker algorithm. Results. We extracted for the first time the JH low-resolution spectrum of HD 95086 b by stacking the six best epochs, and confirm its very red spectral energy distribution. Combined with additional datasets from GPI and NaCo, our analysis indicates that this very red color can be explained by the presence of a circumplanetary disk around planet b, with a range of high-temperature solutions (1400–1600 K) and significant extinction (Av ≳ 10 mag), or by a super-solar metallicity atmosphere with lower temperatures (800–300 K), and small to medium amount of extinction (Av ≲ 10 mag). We do not find any robust candidates for planet c, but give updated constraints on its potential mass and location.
Can Chondrules Be Produced by the Interaction of Jupiter with the Protosolar Disk?
Bodénan, Jean-David; Surville, Clément; Szulágyi, Judit; et al. (2020)
The Astrophysical Journal
Chondrules are crystallized droplets of silicate melt formed by rapid heating to high temperatures (>1800 K) of solid precursors followed by hours or days of cooling. The time interval of chondrule formation is consistent with the formation timescale of Jupiter in the core-accretion model (1–4 Myr). Here we investigate if the shocks generated by a massive planet could generate flash heating episodes necessary to form chondrules using high-resolution 2D simulations with the multifluid code RoSSBi. We use different radiative cooling prescriptions, planet masses, orbits, and disk models. Temperatures reached during flash heating can be deduced from chondrule observations and are achieved in a Minimum Mass Solar Nebula (MMSN) for a massive protoplanet (>0.75 M ♃) but only in cases in which radiative cooling is low enough to lead to nearly adiabatic conditions. More realistic thermodynamics undershoot the temperatures required in shocks for chondrule formation. However, these temperatures are reached when considering more massive disks (e.g., five MMSN), but these conditions lead to fast planet migration and too low cooling rates compared to those deduced from chondrule textures. Thus, it seems unlikely that shocks from Jupiter can form chondrules in most cases. Independent of the nebular mass, the simulations demonstrate that a massive planet that forms a gap triggers vortices, which act as dust traps for chondrule precursors. These vortices also provide a high-pressure environment consistent with cosmochemical evidence from chondrules. They only lack the flash heating source for a potential chondrule formation environment.
Concerning the possible exomoons around Kepler-1625 b and Kepler-1708 b
Kipping, David; Teachey, Alex; Yahalomi, Daniel A.; et al. (2025)
Nature Astronomy
ExoplaNeT accRetion mOnitoring sPectroscopic surveY (ENTROPY): I. Evidence for magnetospheric accretion in the young isolated planetary-mass object 2MASS J11151597+1937266
Viswanath, Gayathri; Ringqvist, Simon C.; Demars, Dorian; et al. (2024)
Astronomy & Astrophysics
Context: Accretion among planetary mass companions is a poorly understood phenomenon, due to the lack of both observational and theoretical studies. The detection of emission lines from accreting gas giants facilitates detailed investigations into this process. Aims: This work presents a detailed analysis of Balmer lines from one of the few known young, planetary-mass objects with observed emission, the isolated L2γ dwarf 2MASS J11151597+1937266 with a mass between 7 and 21 M_Jup and an age of 5–45 Myr, located at 45 ± 2 pc. Methods: We obtained the first high-resolution (R ~ 50 000) spectrum of the target with VLT/UVES, an echelle spectrograph operating in the near-ultraviolet to visible wavelengths (3200–6800 Å). Results: We report several resolved hydrogen (H I; H3–H6) and helium (He I; λ5875.6) emission lines in the spectrum. Based on the asymmetric line profiles of Hα and Hβ, the 10% width of Hα (199 ± 1 km s⁻¹), tentative He I λ6678 emission, and indications of a disk from mid-infrared excess, we confirm ongoing accretion at this object. Using the Gaia update of the parallax, we revise its temperature to 1816 ± 63 K and radius to 1.5 ± 0.1 RJup. Analysis of observed H I profiles using a 1D planet-surface shock model implies a pre-shock gas velocity, v₀ = 120₋₄₀⁺⁸⁰ km s⁻¹, and a pre-shock density, log(n₀/cm⁻³) = 14₋₅⁺⁰. The pre-shock velocity points to a mass, Mₚ = 6−4⁺⁸ M_Jup, for the target. Combining H I line luminosities (L_line) and planetary L_line−L_acc (accretion luminosity) scaling relations, we derived a mass accretion rate, Ṁacc = 1.4₋₀.₉⁺².⁸ × 10⁻⁸ M_Jup yr⁻¹. Conclusions: The line-emitting area predicted from the planet-surface shock model is very small (~0.03%), and points to a shock at the base of a magnetospherically induced funnel. The Hα profile exhibits a much stronger flux than predicted by the model that best fits the rest of the H I profiles, indicating that another mechanism than shock emission contributes to the Hα emission. Comparison of line fluxes and Ṁacc from archival moderate-resolution SDSS spectra indicate variable accretion at 2MASS J11151597+1937266.
Circumplanetary disc or circumplanetary envelope?
Szulágyi, Judit; Masset, Frédéric; Lega, Elena; et al. (2016)
Monthly Notices of the Royal Astronomical Society
We present three-dimensional simulations with nested meshes of the dynamics of the gas around a Jupiter mass planet with the JUPITER and FARGOCA codes. We implemented a radiative transfer module into the JUPITER code to account for realistic heating and cooling of the gas. We focus on the circumplanetary gas flow, determining its characteristics at very high resolution (80 per cent of Jupiter's diameter). In our nominal simulation where the temperature evolves freely by the radiative module and reaches 13000 K at the planet, a circumplanetary envelope was formed filling the entire Roche lobe. Because of our equation of state is simplified and probably overestimates the temperature, we also performed simulations with limited maximal temperatures in the planet region (1000, 1500, and 2000 K). In these fixed temperature cases circumplanetary discs (CPDs) were formed. This suggests that the capability to form a CPD is not simply linked to the mass of the planet and its ability to open a gap. Instead, the gas temperature at the planet's location, which depends on its accretion history, plays also fundamental role. The CPDs in the simulations are hot and cooling very slowly, they have very steep temperature and density profiles, and are strongly sub-Keplerian. Moreover, the CPDs are fed by a strong vertical influx, which shocks on the CPD surfaces creating a hot and luminous shock-front. In contrast, the pressure supported circumplanetary envelope is characterized by internal convection and almost stalled rotation.
SPHERE RefPlanets: Search for ϵ Eridani b and warm dust
Tschudi, C.; Schmid, Hans Martin; Nowak, Matthias M.; et al. (2024)
Astronomy & Astrophysics
Large Interferometer For Exoplanets (LIFE): I. Improved exoplanet detection yield estimates for a large mid-infrared space-interferometer mission
Quanz, Sascha P.; Ottiger, Marcel; Fontanet, E.; et al. (2021)
arXiv
One of the long-term goals of exoplanet science is the atmospheric characterization of dozens of small exoplanets in order to understand their diversity and search for habitable worlds and potential biosignatures. Achieving this goal requires a space mission of sufficient scale. We seek to quantify the exoplanet detection performance of a space-based mid-infrared nulling interferometer that measures the thermal emission of exoplanets. For this, we have developed an instrument simulator that considers all major astrophysical noise sources and coupled it with Monte Carlo simulations of a synthetic exoplanet population around main-sequence stars within 20 pc. This allows us to quantify the number (and types) of exoplanets that our mission concept could detect over a certain time period. Two different scenarios to distribute the observing time among the stellar targets are discussed and different apertures sizes and wavelength ranges are considered. Within a 2.5-year initial search phase, an interferometer consisting of four 2 m apertures covering a wavelength range between 4 and 18.5 μm could detect up to ~550 exoplanets with radii between 0.5 and 6 R⊕ with an integrated SNR≥7. At least ~160 of the detected exoplanets have radii ≤1.5 R⊕. Depending on the observing scenario, ~25-45 rocky exoplanets (objects with radii between 0.5 and 1.5 ⊕) orbiting within the empirical habitable zone (eHZ) of their host stars are among the detections. With four times 3.5 m aperture size, the total number of detections can increase to up to ~770, including ~60-80 rocky, eHZ planets. With four times 1 m aperture size, the maximum detection yield is ~315 exoplanets, including ≤20 rocky, eHZ planets. In terms of predicted detection yield, such a mission can compete with large single-aperture reflected light missions.

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Judit Szulágyi

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