Search Publications
Large exomoons unlikely around Kepler-1625 b and Kepler-1708 b
Heller, René; Hippke, Michael
There are more than 200 moons in our Solar System, but their relatively small radii make similarly sized extrasolar moons very hard to detect with current instruments. The best exomoon candidates so far are two nearly Neptune-sized bodies orbiting the Jupiter-sized transiting exoplanets Kepler-1625 b and Kepler-1708 b, but their existence has been…
Effects of density and temperature variations on the metallicity of Mrk 71
Kreckel, Kathryn; Esteban, César; García-Rojas, Jorge +2 more
In a very recent work, [1] claim that the scenario of temperature inhomogeneities proposed by [2] ($t2$ > 0) is not able to explain the O$^{2+}$/H$^{+}$ abundance discrepancy observed between the calculations based on the optical [OIII] collisional excited lines (CELs) and the OII recombination lines (RLs) in the star forming galaxy Mrk71. In t…
Detection of an Earth-sized exoplanet orbiting the nearby ultracool dwarf star SPECULOOS-3
Ikuta, Kai; Triaud, Amaury H. M. J.; Tamura, Motohide +82 more
Located at the bottom of the main sequence, ultracool dwarf stars are widespread in the solar neighbourhood. Nevertheless, their extremely low luminosity has left their planetary population largely unexplored, and only one of them, TRAPPIST-1, has so far been found to host a transiting planetary system. In this context, we present the SPECULOOS pr…
Magnetic origin of the discrepancy between stellar limb-darkening models and observations
Solanki, Sami K.; Seager, Sara; Shapiro, Alexander I. +8 more
Stars appear darker at their limbs than at their disk centres because at the limb we are viewing the higher and cooler layers of stellar photospheres. Yet, limb darkening derived from state-of-the-art stellar atmosphere models systematically fails to reproduce recent transiting exoplanet light curves from the Kepler, TESS and JWST telescopes—stell…
A low-density ocean inside Titan inferred from Cassini data
Goossens, Sander; van Noort, Bob; Mateo, Alfonso +2 more
The Cassini mission has provided measurements of the gravity of several moons of Saturn as well as an estimate of the tidal response, which is expressed as the degree 2 Love number k2 of its largest moon, Titan. The first estimates of Titan's Love number were larger than pre-Cassini expectations. Interior modelling suggested it may be e…
A slightly oblate dark matter halo revealed by a retrograde precessing Galactic disk warp
Huang, Yang; Liu, Jifeng; Beers, Timothy C. +7 more
The shape of the dark matter (DM) halo is key to understanding the hierarchical formation of the Galaxy. Despite extensive efforts in recent decades, however, its shape remains a matter of debate, with suggestions ranging from strongly oblate to prolate. Here, we present a new constraint on its present shape by directly measuring the evolution of …
X-ray detection of astrospheres around three main-sequence stars and their mass-loss rates
Güdel, M.; Koutroumpa, D.; Lisse, C. M. +3 more
Stellar winds of cool main-sequence stars are difficult to constrain observationally. One way to measure stellar mass-loss rates is to detect the soft X-ray emission from stellar astrospheres produced by charge exchange between heavy ions of the stellar wind and cold neutrals of the interstellar medium surrounding the stars. Here we report detecti…
Chromospheric and coronal heating in an active region plage by dissipation of currents from braiding
De Pontieu, Bart; Hansteen, Viggo; Sainz Dalda, Alberto +3 more
The question of what heats the outer solar atmosphere remains one of the longstanding mysteries in astrophysics. Statistical studies of Sun-like stars reveal a correlation between global chromospheric and coronal emissions, constraining theoretical models of potential heating mechanisms. However, spatially resolved observations of the Sun have sur…
Ionospheric irregularities at Jupiter observed by JWST
Hueso, R.; Sánchez-Lavega, A.; Fletcher, L. N. +22 more
Jupiter's upper atmosphere is composed of a neutral thermosphere and charged ionosphere. In the latter, the dominant molecular ion H3+ emits in the near-infrared, allowing for the remote exploration of the physical properties of the upper atmosphere. However, the Jovian low-latitude ionosphere remains largely unexplored becau…
Heterogeneous outgassing regions identified on active centaur 29P/Schwassmann–Wachmann 1
Schambeau, Charles A.; Villanueva, Geronimo L.; Faggi, Sara +11 more
Centaurs are transitional objects between primitive trans-Neptunian objects and Jupiter-family comets. Their compositions and activities provide fundamental clues regarding the processes affecting the evolution of and interplay between these small bodies. Here we report observations of centaur 29P/Schwassmann–Wachmann 1 (29P) with the James Webb S…