Onderzoeksvragen

In 2024 October, JWST observed a transit of Kepler-167 e, a Jupiter-analog planet on a 1000+ day orbit. These observations, recorded over a long baseline of nearly 60 hr, were designed to search for signatures of planetary oblateness and/or exomoons comparable to Ganymede. In this first in a series of studies analyzing these data, we…

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We present new Rosseland and Planck mean opacity tables relevant to the shallow interiors and atmospheres of giant planets. The tables span metallicities from 0.31 to 50 times solar, temperatures from $100 – 6000 rm K$, and pressures from $10^{-6} – 10^{5} rm bar$, thereby covering a wider parameter space than previous data sets. Our…

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Correctly interpreting JWST spectra of close-in exoplanets requires a measurement of the X-ray and ultraviolet light that the planets receive from their host stars. Here, we provide spectral energy distributions (SEDs) covering the range ≍5─1 × 107 Å for 20 transiting exoplanet host stars observed in JWST Cycle 1. The SEDs are constructed out of…

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We investigate the role of galactic bars in fuelling and triggering active galactic nuclei (AGN) in disc galaxies up to z ∼ 0.8. We utilised a deep learning model, fine-tuned on Galaxy Zoo volunteer classifications, to identify (strongly and weakly) barred and unbarred disc galaxies in Hyper Suprime-Cam Subaru Strategic Program i-band images. We selected…

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James Webb Space Telescope observations provide for the first time evidence for an atmosphere on a rocky exoplanet ─ 55 Cnc e. The atmosphere of 55 Cnc e is hot with ${T}_{text{eq}}gt 2000$ K and shows strong variability, for which cloud formation above a molten crust could be one possible explanation. The composition of the…

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A high-resolution X-ray spectroscopic observation was made of the RS CVn-type binary star HR 1099 using the Resolve instrument onboard XRISM for its calibration purposes. During the $sim$400 ks telescope time covering 1.5 binary orbit, a flare lasting for $sim$100 ks was observed with a released X-ray radiation energy of ${sim }10^{34}$ erg, making it…

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