Search Publications
Water in star-forming regions with Herschel (WISH). III. Far-infrared cooling lines in low-mass young stellar objects
Liseau, R.; Fedele, D.; van Dishoeck, E. F. +22 more
Context. Understanding the physical phenomena involved in the earlierst stages of protostellar evolution requires knowledge of the heating and cooling processes that occur in the surroundings of a young stellar object. Spatially resolved information from its constituent gas and dust provides the necessary constraints to distinguish between differe…
Optical constants of refractory oxides at high temperatures. Mid-infrared properties of corundum, spinel, and α-quartz, potential carriers of the 13 µm feature
Mutschke, H.; Zeidler, S.; Posch, Th.
Context. Many cosmic dust species, among them refractory oxides, form at temperatures higher than 300 K. Nevertheless, most astrophysical studies are based on the room-temperature optical constants of solids, such as corundum and spinel. A more realistic approach is needed for these materials, especially in the context of modeling late-type stars.…
Swift heavy ion irradiation of water ice from MeV to GeV energies. Approaching true cosmic ray compaction
Dartois, E.; Chabot, M.; Brunetto, R. +11 more
Context. Cosmic ray ion irradiation affects the chemical composition of and triggers physical changes in interstellar ice mantles in space. One of the primary structural changes induced is the loss of porosity, and the mantles evolve toward a more compact amorphous state. Previously, ice compaction was monitored at low to moderate ion energies. Th…
Planet or brown dwarf? Inferring the companion mass in HD 100546 from the wall shape using mid-infrared interferometry
van Boekel, Roy; Panić, Olja; Mulders, Gijs D. +3 more
Context. Giant planets form in protoplanetary disks while these disks are still gas-rich, and can reveal their presence through the annular gaps they carve out. HD 100546 is a gas-rich disk with a wide gap between a radius of ~1 and 13 AU, possibly cleared out by a planetary companion or planetary system.
Aims: We aim to identify the nature o…
Large-scale environments of binary AGB stars probed by Herschel. I. Morphology statistics and case studies of R Aquarii and W Aquilae
Blommaert, J. A. D. L.; Jorissen, A.; Ottensamer, R. +14 more
The Mass loss of Evolved StarS (MESS) sample offers a selection of 78 asymptotic giant branch (AGB) stars and red supergiants (RSGs) observed with the PACS photometer on-board Herschel at 70 µm and 160 µm. For most of these objects, the dusty AGB wind is not spherically symmetric and the wind shape can be subdivided into four classes. …
The circumstellar environment and evolutionary state of the supergiant B[e] star Wd1-9
Negueruela, I.; Clark, J. S.; Ritchie, B. W.
Context. Historically, supergiant (sg)B[e] stars have been difficult to include in theoretical schemes for the evolution of massive OB stars.
Aims: The location of Wd1-9 within the coeval starburst cluster Westerlund 1 means that it may be placed into a proper evolutionary context and we therefore aim to utilise a comprehensive multiwavelengt…
OH/IR stars and their superwinds as observed by the Herschel Space Observatory
Waters, L. B. F. M.; Teyssier, D.; Justtanont, K. +4 more
Aims: In order to study the history of mass loss in extreme OH/IR stars, we observed a number of these objects using CO as a tracer of the density and temperature structure of their circumstellar envelopes.
Methods: Combining CO observations from the Herschel Space Observatory with those from the ground, we trace mass loss rates as a fun…
An interferometric study of the post-AGB binary 89 Herculis. I. Spatially resolving the continuum circumstellar environment at optical and near-IR wavelengths with the VLTI, NPOI, IOTA, PTI, and the CHARA Array
Chesneau, O.; Banerjee, D. P. K.; Verhoelst, T. +9 more
Context. Binary post-asymptotic giant branch (post-AGB) stars are interesting laboratories to study both the evolution of binaries as well as the structure of circumstellar disks.
Aims: A multiwavelength high angular resolution study of the prototypical object 89 Herculis is performed with the aim of identifying and locating the different emi…
Gas and dust cooling along the major axis of M 33 (HerM33es). ISO/LWS [C ii] observations
Boquien, M.; Braine, J.; van der Werf, P. +12 more
Aims: We aim to better understand the heating of gas by observing the prominent gas cooling line [C ii] at 158 µm in the low-metallicity environment of the Local Group spiral galaxy M 33 on scales of 280 pc. In particular, we describe the variation of the photoelectric heating efficiency with the galactic environment.
Methods: In t…
Luminosities of carbon-rich asymptotic giant branch stars in the Milky Way
Cristallo, S.; Guandalini, R.
Context. Stars evolving along the asymptotic giant branch can become carbon-rich in the final part of their evolution. They replenish the inter-stellar medium with nuclear processed material via strong radiative stellar winds. The determination of the luminosity function of these stars, even if far from being conclusive, is extremely important for…