Search Publications
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…
Detailed study of a rare hyperluminous rotating disk in an Einstein ring 10 billion years ago
Cresci, Giovanni; Frye, Brenda L.; Yun, Min S. +83 more
Hyperluminous infrared galaxies (HyLIRGs) are the rarest and most extreme starbursts and found only in the distant Universe (z ≳ 1). They have intrinsic infrared (IR) luminosities LIR ≥ 1013 L⊙ and are commonly found to be major mergers. Recently, the Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme …
Observation of the Mars O2 visible nightglow by the NOMAD spectrometer onboard the Trace Gas Orbiter
Vandaele, A. C.; Daerden, F.; Thomas, I. R. +9 more
On Mars, atomic oxygen controls the carbon dioxide radiative cooling of the upper atmosphere and the presence of an ozone layer near the poles. To remotely probe meridional transport of O atoms from the summer to the winter hemisphere and the descending flow in the winter polar regions, the O2 Herzberg II atmospheric emission could be u…
A unified framework for global auroral morphologies of different planets
Merkin, V. G.; Lyon, J. G.; Delamere, P. A. +8 more
Planetary magnetic fields control energetic particles in their space environments and guide particles to polar atmospheres, where they produce stunning auroral forms. As revealed by spacecraft measurements of the Earth, Saturn and Jupiter, the pathways of energetic particles to these planetary polar atmospheres are diverse, suggesting that there a…
BepiColombo observations of cold oxygen and carbon ions in the flank of the induced magnetosphere of Venus
André, N.; Fedorov, A.; Krupp, N. +25 more
On 10 August 2021, the Mercury-bound BepiColombo spacecraft performed its second fly-by of Venus and provided a short-lived observation of its induced magnetosphere. Here we report results recorded by the Mass Spectrum Analyzer on board Mio, which reveal the presence of cold O+ and C+ with an average total flux of ~4 ± 1 × 10…