Search Publications
Extended ammonia observations towards the integral-shaped filament
Qiu, Keping; Li, Dalei; Wu, Gang +4 more
Context. Recent observations suggest a scenario in which filamentary structures in the interstellar medium represent the first step towards clumps/cores and eventually star formation. The densest filaments would then fragment into prestellar cores owing to gravitational instability.
Aims: We seek to understand the roles filamentary structures…
A NIKA view of two star-forming infrared dark clouds: Dust emissivity variations and mass concentration
Aussel, H.; Adam, R.; Benoît, A. +39 more
Context. The thermal emission of dust grains is a powerful tool for probing cold, dense regions of molecular gas in the interstellar medium, and so constraining dust properties is key to obtaining accurate measurements of dust mass and temperature.
Aims: By placing constraints on the dust emissivity spectral index, β, towards two star-forming…
VLTI-GRAVITY measurements of cool evolved stars. I. Variable photosphere and extended atmosphere of the Mira star R Peg
Chiavassa, A.; Wood, P. R.; Höfner, S. +7 more
Context. Dynamic model atmospheres of Mira stars predict variabilities in the photospheric radius and in atmospheric molecular layers which are not yet strongly constrained by observations.
Aims: Here we measure the variability of the oxygen-rich Mira star R Peg in near-continuum and molecular bands.
Methods: We used near-infrared K-band…
Galactic cold cores. IX. Column density structures and radiative-transfer modelling
Juvela, M.; Ristorcelli, I.; Montillaud, J. +3 more
Context. The Galactic Cold Cores (GCC) project has made Herschel photometric observations of interstellar clouds where Planck detected compact sources of cold dust emission. The fields are in different environments and stages of star formation.
Aims: Our aim is to characterise the structure of the clumps and their parent clouds, and to study …
Three-dimensional dust mapping in the Orion complex, combining Gaia-TGAS, 2MASS, and WISE
Bailer-Jones, C. A. L.; Fouesneau, M.; Schlafly, E. F. +1 more
We present a map of the three-dimensional (3D) distribution of dust in the Orion complex. Orion is the closest site of high-mass star formation, making it an excellent laboratory for studying the interstellar medium and star formation. We used data from the Gaia-TGAS catalogue combined with photometry from 2MASS and WISE to get the distances and e…
A quantitative NLTE analysis of visual and ultraviolet spectra of four helium-rich subdwarf O stars
Heber, U.; Latour, M.; Irrgang, A. +4 more
Aims: Hot subdwarf stars represent a poorly understood late phase of stellar evolution. While binary evolution plays an important role for the formation of B-type subdwarfs (sdB), the origin of the helium dominated subclass of O-type subdwarfs (He-sdO) is still unknown. We search for chemical signatures of their genesis by means of quantitati…
The near-nucleus gas coma of comet 67P/Churyumov-Gerasimenko prior to the descent of the surface lander PHILAE
Altwegg, K.; Rubin, M.; Zakharov, V. V. +2 more
Context. The European Space Agency (ESA) Rosetta mission was the most comprehensive study of a comet ever performed. In particular, the Rosetta orbiter, which carried many instruments for monitoring the evolution of the dusty gas emitted by the cometary nucleus, returned an enormous volume of observational data collected from the close vicinity of…
Physical properties of β Lyrae A and its opaque accretion disk
Wolf, M.; Meilland, A.; Baron, F. +23 more
Mass exchange and mass loss in close binaries can significantly affect their evolution, but a complete self-consistent theory of these processes is still to be developed. Processes such as radiative shielding due to a hot-spot region, or a hydrodynamical interaction of different parts of the gas stream have been studied previously. In order to tes…
Solar chromospheric emission and magnetic structures from plages to intranetwork: Contribution of the very quiet Sun
Meunier, N.
Context. We need to establish a correspondence between the magnetic structures generated by models and usual stellar activity indexes to simulate radial velocity time series for stars less active than the Sun. This is necessary to compare the outputs of such models with observed radial velocity jitters and is critical to better understand the impa…
A VST and VISTA study of globular clusters in NGC 253
Greggio, Laura; Rejkuba, Marina; Arnaboldi, Magda +5 more
Context. Globular clusters (GCs) are key to our understanding of the Universe, as laboratories of stellar evolution, fossil tracers of the past formation epoch of the host galaxy, and effective distance indicators from local to cosmological scales. Aim. We analyze the properties of the sources in the NGC 253 with the aim of defining an up to date …