Search Publications
The Cepheid period-luminosity-metallicity relation based on Gaia DR2 data
Groenewegen, M. A. T.
Aims: We use parallax data from the Gaia second data release (GDR2), combined with parallax data based on HIPPARCOS and HST data, to derive the period-luminosity-metallicity (PLZ) relation for Galactic classical cepheids (CCs) in the V, K, and Wesenheit WVK bands.
Methods: An initial sample of 452 CCs are extracted from the literature wi…
Empirical photometric calibration of the Gaia red clump: Colours, effective temperature, and absolute magnitude
Arenou, F.; Babusiaux, C.; Turon, C. +2 more
Context. Gaia Data Release 1 allows the recalibration of standard candles such as the red clump stars. To use those stars, they first need to be accurately characterised. In particular, colours are needed to derive interstellar extinction. As no filter is available for the first Gaia data release and to avoid the atmosphere model mismatch, an empi…
The GJ 504 system revisited. Combining interferometric, radial velocity, and high contrast imaging data
Kuzuhara, M.; Tamura, M.; Rouan, D. +79 more
Context. The G-type star GJ504A is known to host a 3-35 MJup companion whose temperature, mass, and projected separation all contribute to making it a test case for planet formation theories and atmospheric models of giant planets and light brown dwarfs.
Aims: We aim at revisiting the system age, architecture, and companion physica…
Surround and Squash: the impact of superbubbles on the interstellar medium in Scorpius-Centaurus OB2
Roccatagliata, Veronica; Diehl, Roland; Siegert, Thomas +7 more
Context. Feedback by massive stars shapes the interstellar medium and is thought to influence subsequent star formation. The details of this process are under debate.
Aims: We exploited observational constraints on stars, gas, and nucleosynthesis ashes for the closest region with recent massive-star formation, Scorpius-Centaurus OB2, and comb…
Search for Galactic runaway stars using Gaia Data Release 1 and HIPPARCOS proper motions
Lennon, D. J.; Simón-Díaz, S.; Maíz Apellániz, J. +5 more
Context. The first Gaia Data Release (DR1) significantly improved the previously available proper motions for the majority of the Tycho-2 stars.
Aims: We wish to detect runaway stars using Gaia DR1 proper motions and compare our results with previous searches.
Methods: Runaway O stars and BA supergiants were detected using a 2D proper mo…
Low-frequency photospheric and wind variability in the early-B supergiant HD 2905
Grundahl, F.; Fredslund Andersen, M.; Pallé, P. L. +5 more
Context. Despite important advances in space asteroseismology during the last decade, the early phases of evolution of stars with masses above 15 M⊙ (including the O stars and their evolved descendants, the B supergiants) have been only vaguely explored up to now. This is due to the lack of adequate observations for a proper characteriz…
Improving dynamical mass constraints for intermediate-period substellar companions using Gaia DR2
Calissendorff, Per; Janson, Markus
The relationship between luminosity and mass is of fundamental importance for direct imaging studies of brown dwarf and planetary companions to stars. In principle this can be inferred from theoretical mass-luminosity models; however, these relations have not yet been thoroughly calibrated, since there is a lack of substellar companions for which …
A spectroscopic survey of the youngest field stars in the solar neighborhood . II. The optically faint sample
Montes, D.; Gandolfi, D.; Guillout, P. +5 more
Context. Star formation in the solar neighborhood is mainly traced by young stars in open clusters, associations, and in the field, which can be identified, for example, by their X-ray emission. The determination of stellar parameters for the optical counterparts of X-ray sources is crucial for a full characterization of these stars.
Aims: Th…
The Penn State - Toruń Centre for Astronomy Planet Search stars. IV. Dwarfs and the complete sample
Nowak, G.; Adamów, M.; Niedzielski, A. +3 more
Context. Our knowledge of the intrinsic parameters of exoplanets is as precise as our determinations of their stellar hosts parameters. In the case of radial velocity searches for planets, stellar masses appear to be crucial. But before estimating stellar masses properly, detailed spectroscopic analysis is essential. With this paper we conclude a …
Using the CIFIST grid of CO5BOLD 3D model atmospheres to study the effects of stellar granulation on photometric colours. I. Grids of 3D corrections in the UBVRI, 2MASS, HIPPARCOS, Gaia, and SDSS systems
Steffen, M.; Ludwig, H. -G.; Bonifacio, P. +9 more
Context. The atmospheres of cool stars are temporally and spatially inhomogeneous due to the effects of convection. The influence of this inhomogeneity, referred to as granulation, on colours has never been investigated over a large range of effective temperatures and gravities. Aim. We aim to study, in a quantitative way, the impact of granulatio…