Search Publications
Non-LTE chemical abundances in Galactic open and globular clusters
Ting, Yuan-Sen; Kovalev, Mikhail; Rix, Hans-Walter +1 more
Aims: We study the effects of non-local thermodynamic equilibrium (NLTE) on the determination of stellar parameters and abundances of Fe, Mg, and Ti from the medium-resolution spectra of FGK stars.
Methods: We extended the Payne fitting approach to draw on NLTE and LTE spectral models. These were used to analyse the spectra of the Gaia-E…
Stringent limits on the magnetic field strength in the disc of TW Hya. ALMA observations of CN polarisation
Testi, L.; Williams, J. P.; Facchini, S. +8 more
Despite their importance in the star formation process, measurements of magnetic field strength in proto-planetary discs remain rare. While linear polarisation of dust and molecular lines can give insight into the magnetic field structure, only observations of the circular polarisation produced by Zeeman splitting provide a direct measurement of m…
Spatial segregation of dust grains in transition disks. SPHERE observations of 2MASS J16083070-3828268 and RXJ1852.3-3700
Pinte, C.; Ménard, F.; Dent, W. R. F. +27 more
Context. The mechanisms governing the opening of cavities in transition disks are not fully understood. Several processes have been proposed, but their occurrence rate is still unknown.
Aims: We present spatially resolved observations of two transition disks, and aim at constraining their vertical and radial structure using multiwavelength ob…
Blobs, spiral arms, and a possible planet around HD 169142
Henning, T.; Fantinel, D.; D'Orazi, V. +24 more
Context. Young planets are expected to cause cavities, spirals, and kinematic perturbations in protostellar disks that may be used to infer their presence. However, a clear detection of still-forming planets embedded within gas-rich disks is still rare.
Aims: HD 169142 is a very young Herbig Ae-Be star surrounded by a pre-transitional disk, c…
Star-forming content of the giant molecular filaments in the Milky Way
Henning, Th.; Zhang, M.; Fang, M. +2 more
Context. Through observations numerous giant molecular filaments (GMFs) have been discovered in the Milky Way. Their role in the Galactic star formation and Galaxy-scale evolution of dense gas is unknown.
Aims: We investigate systematically the star-forming content of all currently known GMFs. This allows us to estimate the star formation rat…
Euclid preparation. IV. Impact of undetected galaxies on weak-lensing shear measurements
Lilje, P. B.; Scott, D.; Schrabback, T. +22 more
In modern weak-lensing surveys, the common approach to correct for residual systematic biases in the shear is to calibrate shape measurement algorithms using simulations. These simulations must fully capture the complexity of the observations to avoid introducing any additional bias. In this paper we study the importance of faint galaxies below th…
Confirmation of the radial velocity super-Earth K2-18c with HARPS and CARMENES
Bouchy, F.; Doyon, R.; Bonfils, X. +13 more
In an earlier campaign to characterize the mass of the transiting temperate super-Earth K2-18b with HARPS, a second, non-transiting planet was posited to exist in the system at 9 days. Further radial velocity follow-up with the CARMENES spectrograph visible channel revealed a much weaker signal at 9 days, which also appeared to vary chromatically …
Rotation rate of the solar core as a key constraint to magnetic angular momentum transport in stellar interiors
Buldgen, G.; Eggenberger, P.; Salmon, S. J. A. J.
Context. The internal rotation of the Sun constitutes a fundamental constraint when modelling angular momentum transport in stellar interiors. In addition to the more external regions of the solar radiative zone probed by pressure modes, measurements of rotational splittings of gravity modes would offer an invaluable constraint on the rotation of …
An alternative interpretation of the exomoon candidate signal in the combined Kepler and Hubble data of Kepler-1625
Heller, René; Rodenbeck, Kai; Bruno, Giovanni
Context. Kepler and Hubble photometry of a total of four transits by the Jupiter-sized exoplanet Kepler-1625 b have recently been interpreted to show evidence of a Neptune-sized exomoon. The key arguments were an apparent drop in stellar brightness after the planet's October 2017 transit seen with Hubble and its 77.8 min early arrival compared to …
VISION - Vienna survey in Orion. III. Young stellar objects in Orion A
Meingast, Stefan; Alves, João; Bouy, Hervé +14 more
We have extended and refined the existing young stellar object (YSO) catalogs for the Orion A molecular cloud, the closest massive star-forming region to Earth. This updated catalog is driven by the large spatial coverage (18.3 deg2, ∼950 pc2), seeing limited resolution (∼0.7″), and sensitivity (Ks < 19 mag) of …