Related papers: Dusty Blue Supergiants: News from High-Angular Res…
The phenomenon of spectral mimicry refers to the fact that hypergiants and post-AGB supergiants - stars of different masses in fundamentally different stages of their evolution have similar optical spectra, and also share certain other…
We have conducted the first systematic study of Herbig Ae/Be stars using the technique of long baseline stellar interferometry in the near-infrared. The principal result of this paper is that the IOTA interferometer resolves the source of…
Debris discs are commonly detected orbiting main-sequence stars, yet little is known regarding their fate as the star evolves to become a giant. Recent observations of radial velocity detected planets orbiting giant stars highlight this…
We present spectrophotometric data from 0.4 to 4.2 microns for bright, northern sky, Be stars and several other types of massive stars. Our goal is to use these data with ongoing, high angular resolution, interferometric observations to…
Blue supergiants (BSGs) are important objects to study the intermediate phases of massive star evolution, helping to constrain evolutionary models. However, the lack of a holistic study of a statistically significant and unbiased sample of…
Over the past decade the study of solar-like oscillations in red-giant stars has developed significantly. Not only the number of red-giant stars for which solar-like oscillations have been observed has increased, but the quality of these…
Using Gaia DR3 we derive new distances and luminosities for a sample of Galactic B supergiants which were thought to be post main-sequence (MS) objects from their HR diagram location beyond the terminal-age MS (TAMS). When applying the…
The JWST discovery of a number of super-early (redshift $z>10$), blue galaxies requires these systems to be essentially dust-free in spite of their large stellar masses. A possible explanation is that dust is evacuated by radiatively-driven…
High resolution spectra of 110 selected red giant stars in the globular cluster M15 (NGC 7078) were obtained with Hectochelle at the MMT telescope in 2005 May, 2006 May, and 2006 October. Echelle orders containing Halpha and Ca H & K are…
We present the first high angular resolution observation of the B[e] star/X-ray transient object CI Cam, performed with the two-telescope Infrared Optical Telescope Array (IOTA), its upgraded three-telescope version (IOTA3T) and the Palomar…
The specific characteristic of the SED of serendipitously discovered post-AGB binaries, allowed us to launch a very extensive multi-wavelength study of evolved objects, selected on the basis of very specific selection criteria. Those…
We report optical spectroscopic observations of four blue-excess dust-obscured galaxies (BluDOGs) identified by Subaru Hyper Suprime-Cam. BluDOGs are a sub-class of dust-obscured galaxies (DOGs, defined with the extremely red color…
Intermediate-mass stars end their lives by ejecting the bulk of their envelope via a slow dense wind back into the interstellar medium, to form the next generation of stars and planets. Stellar pulsations are thought to elevate gas to an…
Popular models for the origin of gamma-ray bursts (GRBs) include short-lived massive stars as the progenitors of the fireballs. Hence the redshift distribution of GRBs should track the cosmic star formation rate of massive stars accurately.…
A review is presented of the most relevant results obtained in the last few years on this rare class of astronomical sources. Multi-wavelength analysis of an increasing number of post-AGB stars reveal that they constitute a more…
We obtained high-resolution near-IR spectra of 45 AGB stars located in the Galactic bulge. The aim of the project is to determine key elemental abundances in these stars to help constrain the formation history of the bulge. A further aim is…
Galaxies reside in extended dark matter halos, but their baryonic content, especially dust, remains less well understood. We aim to investigate the amount and distribution of dust in galactic halos by measuring shifts in the observed…
This article presents recent work to constrain the physical and chemical properties in high-mass star formation based largely on interferometric high-spatial-resolution continuum and spectral line studies at (sub)mm wavelengths. After…
The role of episodic mass loss in massive star evolution is one of the most important open questions of current stellar evolution theory. Episodic mass loss produces dust and therefore causes evolved massive stars to be very luminous in the…
Blue supergiant stars are known to display photometric and spectroscopic variability that is suggested to be linked to stellar pulsations. Pulsational activity in massive stars strongly depends on the star's evolutionary stage and is…