Search Publications
Gaia Data Release 2. All-sky classification of high-amplitude pulsating stars
Szabados, L.; Audard, M.; Plachy, E. +23 more
Context. More than half a million of the 1.69 billion sources in Gaia Data Release 2 (DR2) are published with photometric time series that exhibit light variations during the 22 months of observation.
Aims: An all-sky classification of common high-amplitude pulsators (Cepheids, long-period variables, δ Scuti/SX Phoenicis, and RR Lyrae stars) …
Abundances and kinematics of carbon-enhanced metal-poor stars in the Galactic halo. A new classification scheme based on Sr and Ba
Hansen, C. J.; Nordström, B.; Andersen, J. +4 more
Carbon-enhanced metal-poor (CEMP) stars span a wide range of stellar populations, from bona fide second-generation stars to later-forming stars that provide excellent probes of binary mass transfer and stellar evolution. Here we analyse 11 metal-poor stars (8 of which are new to the literature), and demonstrate that 10 are CEMP stars. Based on hig…
The bimodal [Mg/Fe] versus [Fe/H] bulge sequence as revealed by APOGEE DR14
Schultheis, M.; Minniti, D.; Recio-Blanco, A. +5 more
Context. The Galactic bulge has a bimodal metallicity distribution function: different kinematic, spatial, and, potentially, age distributions characterize the metal-poor and metal-rich components. Despite this observed dichotomy, which argues for different formation channels for those stars, the distribution of bulge stars in the α-abundance vers…
Aliphatic and aromatic hydrocarbons in comet 67P/Churyumov-Gerasimenko seen by ROSINA
Altwegg, K.; Balsiger, H.; Fuselier, S. A. +10 more
Context. Unlike all previous cometary space missions, the Rosetta spacecraft accompanied its target, comet 67P/Churyumov-Gerasimenko, for more than two years on its way around the Sun. Thereby, an unexpected diversity and complexity of the chemical composition was revealed.
Aims: Our first step of decrypting the exact chemical composition of …
J-PLUS: Identification of low-metallicity stars with artificial neural networks using SPHINX
Caballero, J. A.; Mendes de Oliveira, C.; Beers, T. C. +24 more
Context. We present a new methodology for the estimation of stellar atmospheric parameters from narrow- and intermediate-band photometry of the Javalambre Photometric Local Universe Survey (J-PLUS), and propose a method for target pre-selection of low-metallicity stars for follow-up spectroscopic studies. Photometric metallicity estimates for star…
The VANDELS survey: the role of ISM and galaxy physical properties in the escape of Lyα emission in z ∼ 3.5 star-forming galaxies
Maccagni, D.; Schaerer, D.; Finkelstein, S. L. +21 more
Aims: We wish to investigate the physical properties of a sample of Lyα emitting galaxies in the VANDELS survey, with particular focus on the role of kinematics and neutral hydrogen column density in the escape and spatial distribution of Lyα photons.
Methods: From all the Lyα emitting galaxies in the VANDELS Data Release 2 at 3.5 ≲ z ≲ …
The Hubble PanCET program: an extensive search for metallic ions in the exosphere of GJ 436 b
Sanz-Forcada, J.; Ehrenreich, D.; Lecavelier des Etangs, A. +15 more
Context. The quiet M2.5 star GJ 436 hosts a warm Neptune that displays an extended atmosphere that dwarfs its own host star. Predictions of atmospheric escape in such planets state that H atoms escape from the upper atmosphere in a collisional regime and that the flow can drag heavier atoms to the upper atmosphere. It is unclear, however, what ast…
Plasmoid-mediated reconnection in solar UV bursts
Peter, H.; Chitta, L. P.; Young, P. R. +1 more
Context. Ultraviolet bursts are transients in the solar atmosphere with an increased impulsive emission in the extreme UV lasting for one to several tens of minutes. They often show spectral profiles indicative of a bi-directional outflow in response to magnetic reconnection.
Aims: To understand UV bursts, we study how motions of magnetic ele…
X-shooter spectroscopy of young stars with disks. The TW Hydrae association as a probe of the final stages of disk accretion
Alcalá, J. M.; Randich, S.; Scholz, A. +9 more
Context. Measurements of the fraction of disk-bearing stars in clusters as a function of age indicate protoplanetary disk lifetimes ≲10 Myr. However, our knowledge of the time evolution of mass accretion in young stars over the disk lifespans is subject to many uncertainties, especially at the lowest stellar masses (M⋆).
Aims: We i…
J-PLUS: photometric calibration of large-area multi-filter surveys with stellar and white dwarf loci
Hernández-Monteagudo, C.; Carrasco, J. M.; Tremblay, P. -E. +24 more
Aims: We present the photometric calibration of the 12 optical passbands observed by the Javalambre Photometric Local Universe Survey (J-PLUS).
Methods: The proposed calibration method has four steps: (i) definition of a high-quality set of calibration stars using Gaia information and available 3D dust maps; (ii) anchoring of the J-PLUS …