Search Publications
Comparative study of photo-produced ionosphere in the close environment of comets
Galand, M.; Beth, A.; Heritier, K. L.
Context. The Giotto and Rosetta missions gave us the unique opportunity of probing the close environment of cometary ionospheres of 1P/Halley (1P) and 67P/Churyumov-Gerasimenko (67P). The plasma conditions encountered at these two comets were very different from each other, which mainly stem from the different heliocentric distances, which drive p…
Influence of inelastic collisions with hydrogen atoms on the non-local thermodynamic equilibrium line formation for Fe I and Fe II in the 1D model atmospheres of late-type stars
Yakovleva, S. A.; Belyaev, A. K.; Sitnova, T. +1 more
Context. Iron plays a crucial role in studies of late-type stars. In their atmospheres, neutral iron is the minority species, and lines of Fe I are subject to the departures from local thermodynamic equilibrium (LTE). In contrast, one believes that LTE is a realistic approximation for Fe II lines. The main source of the uncertainties in the non-LT…
A merger shock in Abell 1367
Jones, Christine; Rudnick, Lawrence; Fossati, Matteo +10 more
Multiwavelength observations show that Abell 1367 (A1367) is a dynamically young cluster, with at least two subclusters merging along the SE-NW direction. With the wide-field XMM-Newton mosaic of A1367, we discover a previously unknown merger shock at the NW edge of the cluster. We estimate the shock Mach number from the density and temperature ju…
Storms or systematics? The changing secondary eclipse depth of WASP-12b
de Mooij, Ernst J. W.; Gibson, Neale P.; Watson, Christopher A. +4 more
WASP-12b is one of the most well-studied transiting exoplanets, as its highly inflated radius and its 1.1 d orbit around a G0-type star make it an excellent target for atmospheric categorization through observation during its secondary eclipse. We present two new secondary eclipse observations of WASP-12b, acquired an year apart with the Wide Fiel…
ARGOS at the LBT. Binocular laser guided ground-layer adaptive optics
Genzel, R.; Quirrenbach, A.; Beckmann, U. +48 more
Having completed its commissioning phase, the Advanced Rayleigh guided Ground-layer adaptive Optics System (ARGOS) facility is coming online for scientific observations at the Large Binocular Telescope (LBT). With six Rayleigh laser guide stars in two constellations and the corresponding wavefront sensing, ARGOS corrects the ground-layer distortio…
The TeV-emitting radio galaxy 3C 264. VLBI kinematics and SED modeling
Vignali, C.; Grandi, P.; Boccardi, B. +5 more
Context. In March 2018, the detection by VERITAS of very-high-energy emission (VHE > 100 GeV) from 3C 264 was reported. This is the sixth, and second most distant, radio galaxy ever detected in the TeV regime.
Aims: In this article we present a radio and X-ray analysis of the jet in 3C 264. We determine the main physical parameters of the …
Accurate mass and radius determinations of a cool subdwarf in an eclipsing binary
Rebassa-Mansergas, Alberto; Parsons, Steven G.; Torres, Santiago +4 more
Cool subdwarfs are metal-poor low-mass stars that formed during the early stages of the evolution of our Galaxy. Because they are relatively rare in the vicinity of the Sun, we know of few cool subdwarfs in the solar neighbourhood, and none for which both the mass and the radius are accurately determined. This hampers our understanding of stars at…
The Role of Clathrate Formation in Europa’s Ocean Composition
Mousis, Olivier; Bouquet, Alexis; Danger, Grégoire +2 more
We use a thermodynamic statistical model to evaluate how the composition of Europa’s internal ocean may have been affected by clathrate hydrate formation. Assuming an input of the observed O2 and CO2 from the surface into a mildly acidic ocean (pH < 6), and considering the possibility of contributions by reduced (with CH
The Storm-Time Ring Current Response to ICMEs and CIRs Using Van Allen Probe Observations
Mitchell, D. G.; Farrugia, C. J.; Kistler, L. M. +6 more
Using Van Allen Probe observations of the inner magnetosphere during geomagnetic storms driven by interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs), we characterize the impact of these drivers on the storm-time ring current development. Using 25 ICME- and 35 CIR-driven storms, we have determined the ring curre…
The second-degree gravity coefficients of Phobos from two Mars Express flybys
Pätzold, M.; Hahn, M.; Andert, T. +6 more
Several close spacecraft flybys of Phobos have been performed over the past 40 yr in order to determine the gravity field of this tiny Martian moon. In this work, the second-degree coefficients of the gravity field of Phobos were derived from the radio tracking data of two combined Mars Express flybys (2010 and 2013), by applying a least squares r…