Search Publications
Analysing the SEDs of protoplanetary disks with machine learning
Pinte, C.; Woitke, P.; Kamp, I. +2 more
Context. The analysis of spectral energy distributions (SEDs) of protoplanetary disks to determine their physical properties is known to be highly degenerate. Hence, a full Bayesian analysis is required to obtain parameter uncertainties and degeneracies. The main challenge here is computational speed, as one proper full radiative transfer model re…
ED-2: A cold but not so narrow stellar stream crossing the solar neighbourhood
Helmi, A.; Balbinot, E.; Ruiz-Lara, T. +3 more
Context. ED-2 is a stellar stream identified as a compact group in integrals-of-motion space in a local sample of halo stars from the third Gaia data release.
Aims: We investigate its nature and possible association with known halo substructures.
Methods: We explored the current properties of ED-2 members in phase-space and also analysed…
The Araucaria project: High-precision orbital parallaxes and masses of binary stars. I. VLTI/GRAVITY observations of ten double-lined spectroscopic binaries
Kervella, P.; Mérand, A.; Gallenne, A. +4 more
Aims: We aim to measure very precise and accurate model-independent masses and distances of detached binary stars. Precise masses at the < 1% level are necessary to test and calibrate stellar interior and evolution models, while precise and independent orbital parallaxes are essential to check for the next Gaia data releases.
Methods:…
The Gaia-ESO Survey: Chemical evolution of Mg and Al in the Milky Way with machine learning
Gilmore, G.; Bayo, A.; Guiglion, G. +15 more
Context. To take full advantage of upcoming large-scale spectroscopic surveys, it will be necessary to parameterize millions of stellar spectra in an efficient way. Machine learning methods, especially convolutional neural networks (CNNs), will be among the main tools geared at achieving this task.
Aims: We aim to prepare the groundwork for m…
Extending the extinction law in 30 Doradus to the infrared with JWST
Fahrion, Katja; De Marchi, Guido
We measured the extinction law in the 30 Dor star formation region in the Large Magellanic Cloud using Early Release Observations (EROs) taken with Near-Infrared Camera (NIRCam) on board the JWST, thereby extending previous studies carried out with the Hubble Space Telescope to the infrared. We used red clump stars to derive the direction of the r…
2D chemical evolution models. II. Effects of multiple spiral arm patterns on O, Eu, Fe, and Ba abundance gradients
Recio-Blanco, A.; Palicio, P. A.; Poggio, E. +7 more
Context. According to observations and numerical simulations, the Milky Way could exhibit several spiral-arm modes of various pattern speeds, with the slower patterns located at larger galactocentric distances.
Aims: Our aim is to quantify the effects of the spiral arms on the azimuthal variations in the chemical abundances of oxygen and iron…
Mass-ratio distribution of contact binary stars
Pejcha, Ondřej; Pešta, Milan
The mass ratio q of a contact binary star evolves through mass transfer, magnetic braking, and thermal relaxation oscillations to low values until it crosses a critical threshold qmin. When this occurs, the binary undergoes the tidal Darwin instability, leading to a rapid coalescence of the components and to an observable brightening of…
A major asymmetric ice trap in a planet-forming disk. IV. Nitric oxide gas and a lack of CN tracing sublimating ices and a C/O ratio <1
van der Marel, N.; van Dishoeck, E. F.; Tabone, B. +5 more
Context. Most well-resolved disks observed with the Atacama Large Millimeter/submillimeter Array (ALMA) show signs of dust traps. These dust traps set the chemical composition of the planet-forming material in these disks, as the dust grains with their icy mantles are trapped at specific radii and could deplete the gas and dust at smaller radii of…
Evidence of an age gradient along the line of sight in the nuclear stellar disc of the Milky Way
Schultheis, M.; Rich, R. M.; Najarro, F. +3 more
Context. The nuclear stellar disc (NSD) is a flat dense stellar structure at the heart of the Milky Way. Recent work has shown that analogous structures are common in the nuclei of external spiral galaxies, where there is evidence of an age gradient that indicates that they form inside-out. However, the characterisation of the age of the NSD stell…
Two super-Earths at the edge of the habitable zone of the nearby M dwarf TOI-2095
Amado, P. J.; Caballero, J. A.; Pallé, E. +41 more
The main scientific goal of TESS is to find planets smaller than Neptune around stars that are bright enough to allow for further characterization studies. Given our current instrumentation and detection biases, M dwarfs are prime targets in the search for small planets that are in (or near) the habitable zone of their host star. In this work, we …