Search Publications
Clouds form on the hot Saturn JWST ERO target WASP-96b
Helling, Ch.; Min, M.; Carone, L. +3 more
Context. WASP-96b is a hot Saturn exoplanet, with an equilibrium temperature of ≈1300 K. This is well within the regime of thermo-dynamically expected extensive cloud formation. Prior observations with Hubble/WFC3, Spitzer/IRAC, and VLT/FORS2 have been combined into a single spectrum for which retrievals suggest a cold but cloud-free atmosphere. R…
Spiral-like features in the disc revealed by Gaia DR3 radial actions
Recio-Blanco, A.; Antoja, T.; McMillan, P. J. +3 more
Context. The so-called action variables are specific functions of the positions and velocities that remain constant along the stellar orbit. The astrometry provided by Gaia Early Data Release 3 (EDR3), combined with the velocities inferred from the Radial Velocity Spectrograph (RVS) spectra of Gaia DR3, allows for the estimation of these actions f…
SRG/eROSITA X-ray shadowing study of giant molecular clouds
Ponti, G.; Freyberg, M. J.; Sasaki, M. +3 more
Context. SRG/eROSITA is situated in a halo orbit around L2 where the highly variable solar wind charge exchange (SWCX) emission from Earth's magnetosheath is expected to be negligible. The soft X-ray foreground emissions from the local hot bubble (LHB) and the remaining heliospheric SWCX emissions could be studied in unprecedented detail with eROS…
New insights on the near-infrared veiling of young stars using CFHT/SPIRou data
Carmona, A.; Donati, J. -F.; Doyon, R. +9 more
Context. Veiling is ubiquitous at different wavelength ranges in classical T Tauri stars. However, the origin of the veiling in the infrared (IR) domain is not well understood at present. The accretion spot alone is not enough to explain the shallow photospheric IR lines in accreting systems, suggesting that another source is contributing to the v…
Barium and related stars, and their white-dwarf companions. III. The masses of the white dwarfs
Escorza, A.; De Rosa, R. J.
Context. Masses are one of the most difficult stellar properties to measure. In the case of the white-dwarf (WD) companions of Barium (Ba) stars, the situation is worse. These stars are dim, cool, and difficult to observe via direct methods. However, Ba stars were polluted by the asymptotic giant branch (AGB) progenitors of these WDs with matter r…
Polarimetry of hydrogen-poor superluminous supernovae
Sollerman, J.; Gal-Yam, A.; Wheeler, J. C. +11 more
We present linear polarimetry for seven hydrogen-poor superluminous supernovae (SLSNe-I) of which only one has previously published polarimetric data. The best-studied event is SN 2017gci, for which we present two epochs of spectropolarimetry at +3 d and +29 d post-peak in rest frame, accompanied by four epochs of imaging polarimetry up to +108 d.…
Examining the orbital decay targets KELT-9 b, KELT-16 b, and WASP-4b, and the transit-timing variations of HD 97658 b
Alonso, R.; Deleuil, M.; Erikson, A. +87 more
Context. Tidal orbital decay is suspected to occur for hot Jupiters in particular, with the only observationally confirmed case of this being WASP-12b. By examining this effect, information on the properties of the host star can be obtained using the so-called stellar modified tidal quality factor Q*', which describes the eff…
Gaia Data Release 3. Stellar chromospheric activity and mass accretion from Ca II IRT observed by the Radial Velocity Spectrometer
Hatzidimitriou, D.; Marshall, D. J.; Andretta, V. +82 more
Context. The Gaia Radial Velocity Spectrometer (RVS) provides the unique opportunity of a spectroscopic analysis of millions of stars at medium resolution (λ/Δλ ∼ 11 500) in the near-infrared (845−872 nm). This wavelength range includes the Ca II infrared triplet (IRT) at 850.03, 854.44, and 866.45 nm, which is a good indicator of magnetic activit…
Optical and mid-infrared line emission in nearby Seyfert galaxies
Pozzi, F.; Feltre, A.; Marchetti, L. +24 more
Line ratio diagnostics provide valuable clues as to the source of ionizing radiation in galaxies with intense black hole accretion and starbursting events, such as local Seyfert galaxies or galaxies at the peak of their star formation history. We aim to provide a reference joint optical and mid-IR line ratio analysis for studying active galactic n…
Investigating the visible phase-curve variability of 55 Cnc e★
Alonso, R.; Deleuil, M.; Erikson, A. +87 more
Context. 55 Cnc e is an ultra-short period super-Earth transiting a Sun-like star. Previous observations in the optical range detected a time-variable flux modulation that is phased with the planetary orbital period, whose amplitude is too large to be explained by reflected light and thermal emission alone.
Aims: The goal of the study is to i…