Related papers: New Luminous ON Spectra from the Galactic O-Star S…
We have analyzed six OB supergiants and one giant covering spectral types from O3 to B1 in the Galactic OB association Cyg OB2 by means of an updated version of FASTWIND (SAntolaya-Rey, Puls, Herrero, 1997, A&A 323, 348) that includes an…
A new type of high-energy binary system has been revealed by the INTEGRAL satellite. These sources are being unveiled by means of multi-wavelength optical, near- and mid-infrared observations. Among these sources, two distinct classes are…
We present a massive spectroscopic survey of Galactic O stars, GOSSS, based on new, high signal-to-noise ratio, R~2500 blue-violet digital observations from both hemispheres. The sample size and selection criteria; the relationship between…
The transition from early Of stars to WN type objects is poorly understood. O-type supergiants with emission lines (OIf+) are considered to be intermediate between these two classes. The scope of this paper is to investigate the spectral…
We present an atlas composed of more than 1500 spectra of late-type stars (spectral types from G to M) observed simultaneously in the optical and calcium triplet spectral ranges. These spectra were obtained as part of a survey to search for…
With an aim to investigate how the surface abundances of intermediate-mass stars off the main sequence (evolving toward the red-giant stage) are affected by the evolution-induced envelope mixing, we spectroscopically determined the…
Massive stars play a key role in the evolution of the Universe. Our goal is to compare observed and predicted properties of single Galactic O stars to identify and constrain uncertain physical parameters and processes in stellar evolution…
The spectra of two early B-type supergiant stars in the Sculptor spiral galaxy NGC 300 are analysed by means of non-LTE line blanketed unified model atmospheres, aimed at determining their chemical composition and the fundamental stellar…
New Planetary Nebulae (PNe) were discovered through an [O III] 5007 A emission line survey in the Galactic bulge region with l>0 deg. We detected 240 objects, including 44 new PNe. Deep Halpha+[N II] CCD images as well as low resolution…
We present mid-infrared observations for a sample of 16 O-type stars. The data were acquired with the NASA Spitzer Space Telescope, using the IRS instrument at moderate resolution (R $\sim$ 600), covering the range $\sim 10-37$ microns. Our…
Our knowledge of the chemical properties of the circumstellar ejecta of the most massive evolved stars is particularly poor. We aim to study the chemical characteristics of the prototypical yellow hypergiant star, IRC +10420. For this…
This is the third installment of GOSSS, a massive spectroscopic survey of Galactic O stars, based on new homogeneous, high signal-to-noise ratio, R~2500 digital observations selected from the Galactic O-Star Catalog (GOSC). In this paper we…
The 2008 optical transient in NGC 300 is one of a growing class of intermediate-luminosity transients that brighten several orders of magnitude from a previously optically obscured state. The origin of their eruptions is not understood. Our…
We present a narrow-band imaging survey of the Large Magellanic Cloud, designed to isolate the C II $\lambda\lambda$7231, 7236 emission lines in objects as faint as $m_{\lambda7400}\sim18$. The work is motivated by the recent serendipitous…
High-resolution UCLES/AAT spectra are presented for nine B-type supergiants in the SMC, chosen on the basis that they may show varying amounts of nuclear-synthetically processed material mixed to their surface. These spectra have been…
Analysis of late O-type stars observed in the Large Magellanic Cloud (LMC) by the VLT-FLAMES Tarantula Survey (VFTS) revealed a discrepancy between the physical properties estimated from model-atmosphere analysis and those expected from…
We aim to constrain the properties and evolutionary status of early and mid-spectral type supergiants (from O4 to O7.5). These posses the highest mass-loss rates among the O stars, and exhibit conspicuous wind profiles. Using the non-LTE…
The systematics of OB spectra are reviewed in the optical domain, dominated by photospheric lines, and in the far ultraviolet (both IUE and FUSE ranges), in which the stellar-wind profiles dominate. First, the two-dimensional (temperature,…
A new type of sources has been discovered by INTEGRAL. These sources are in the course of being unveiled by means of multi-wavelength optical, near- and mid-infrared observations. Among the high-energy binary sources, two distinct classes…
The spectra of stars with the B[e] phenomenon are dominated by features that are related to physical conditions of circumstellar material around these objects and are not intrinsic to the stars. Because of this, they form a very…