Search Publications
Greening of the brown-dwarf desert. EPIC 212036875b: a 51 MJ object in a 5-day orbit around an F7 V star
Cochran, William D.; Endl, Michael; Redfield, Seth +55 more
Context. Although more than 2000 brown dwarfs have been detected to date, mainly from direct imaging, their characterisation is difficult due to their faintness and model-dependent results. In the case of transiting brown dwarfs, however, it is possible to make direct high-precision observations.
Aims: Our aim is to investigate the nature and…
Multi-wavelength variability of the young solar analog ι Horologii. X-ray cycle, star spots, flares, and UV emission
Sanz-Forcada, J.; Stelzer, B.; Raetz, S. +2 more
Context. Chromospheric activity cycles are common in late-type stars; however, only a handful of coronal activity cycles have been discovered. ι Hor is the most active and youngest star with known coronal cycles. It is also a young solar analog, and we are likely facing the earliest cycles in the evolution of solar-like stars, at an age ( 600 Myr)…
Using ALMA to resolve the nature of the early star-forming large-scale structure PLCK G073.4-57.5
Frye, Brenda; Hill, Ryley; Béthermin, Matthieu +10 more
Galaxy clusters at high redshift are key targets for understanding matter assembly in the early Universe, yet they are challenging to locate. A sample of more than 2000 high-z candidate structures has been found using Planck's all-sky submillimetre maps, and a sub-set of 234 have been followed up with Herschel-SPIRE, which showed that the emission…
The AMBRE Project: [Y/Mg] stellar dating calibration with Gaia
Titarenko, A.; Recio-Blanco, A.; de Laverny, P. +2 more
Chemical abundance dating methods open new paths for temporal evolution studies of the Milky Way stellar populations. In this paper, we use a high spectral resolution database of turn-off stars in the solar neighbourhood to study the age dependence of the [Y/Mg] chemical abundance ratio. Our analysis reveals a clear correlation between [Y/Mg] and …
Solar wind charge exchange in cometary atmospheres. III. Results from the Rosetta mission to comet 67P/Churyumov-Gerasimenko
Alho, Markku; Simon Wedlund, Cyril; Nilsson, Hans +12 more
Context. Solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet. The ESA/Rosetta mission to comet 67P/Churyumov-Gerasimenko (67P) provides a unique opportunity to study charge-changing processes in situ.
Aims: To understand the role of these reactions in the evolution of the sola…
Precise radial velocities of giant stars. XII. Evidence against the proposed planet Aldebaran b
Trifonov, Trifon; Stock, Stephan; Reffert, Sabine +2 more
Context. Radial-velocity variations of the K giant star Aldebaran (α Tau) were first reported in the early 1990s. After subsequent analyses, the radial-velocity variability with a period of ∼629 d has recently been interpreted as caused by a planet of several Jovian masses.
Aims: We want to further investigate the hypothesis of an extrasolar …
Properties of central stars of planetary nebulae with distances in Gaia DR2
Dafonte, C.; González-Santamaría, I.; Manteiga, M. +2 more
Context. We have compiled a catalogue of central stars of planetary nebulae (CSPN) with reliable distances and positions obtained from Gaia Data Release 2 (DR2) astrometry. Distances derived from parallaxes allow us to analyse the galactic distribution and estimate other parameters such as sizes, kinematical ages, bolometric magnitudes, and lumino…
Revisiting Kepler-444. I. Seismic modeling and inversions of stellar structure
Buldgen, G.; Farnir, M.; Khan, S. +10 more
Context. The CoRoT and Kepler missions have paved the way for synergies between exoplanetology and asteroseismology. The use of seismic data helps providing stringent constraints on the stellar properties which directly impact the results of planetary studies. Amongst the most interesting planetary systems discovered by Kepler, Kepler-444 is uniqu…
Deriving the Hubble constant using Planck and XMM-Newton observations of galaxy clusters
Mazzotta, Pasquale; Sereno, Mauro; Rasia, Elena +2 more
The possibility of determining the value of the Hubble constant using observations of galaxy clusters in X-ray and microwave wavelengths through the Sunyaev Zel'dovich (SZ) effect has long been known. Previous measurements have been plagued by relatively large errors in the observational data and severe biases induced, for example, by cluster tria…
H/C elemental ratio of the refractory organic matter in cometary particles of 67P/Churyumov-Gerasimenko
Alexander, C.; Hilchenbach, M.; Engrand, C. +11 more
Context. Because comets are part of the most primitive bodies of our solar system, establishing their chemical composition and comparing them to other astrophysical bodies gives new constraints on the formation and evolution of organic matter throughout the solar system. For two years, the time-of-flight secondary ion mass spectrometer COmetary Se…