Related papers: Stars with the B[e] phenomenon seen by long baseli…
HH 50138 is one of the brightest B[e] stars at a distance of $\sim$ 380 pc with strong infrared excess. The star was observed in [O I] 63 $\mu$m and [C II] 158 $\mu$m with high velocity resolution with upGREAT on SOFIA. The velocity…
Variability is a commonly observed property of classical Be stars (CBe) stars. In extreme cases, complete disappearance of the H{\alpha} emission line occurs, indicating a disc-less state in CBe stars. The disc-loss and reappearing phases…
Recent studies show that more than 70% of massive stars do not evolve as effectively single stars, but as members of interacting binary systems. The evolution of these stars is thus strongly altered compared to similar but isolated objects.…
The presence of three more Herbig Ae/Be (HAeBe) stars in the Cepheus Flare within a 1.5$^{\circ}$ radius centered on HD 200775 suggests that star formation is prevalent in a wider region of the LDN 1147/1158, LDN 1172/1174, and LDN 1177…
It is already accepted that Be stars are surrounded by circumstellar envelopes, which are mostly compatible with a disc geometry in Keplerian rotation. We aim to obtain a more complete characterisation of the properties of the circumstellar…
We present high resolution (lambda / Delta_lambda = 49000) echelle spectra of the intermediate mass, pre-main sequence stars BF Ori, SV Cep, WW Wul and XY Per. The spectra cover the range 3800-5900 angstroms and monitor the stars on time…
The Be stars display variable optical emission lines originating in the circumstellar disc. Here we analyse high resolution spectroscopic observations of Be stars and the distance between the peaks of H-alpha, H-beta, and H-gamma emission…
The disc formation mechanism of B[e] supergiants is one of the puzzling phenomena in massive star evolution. Rapid stellar rotation seems to play an important role for the non-spherically symmetric mass-loss leading to a high-density disc…
The near-star environment around obscured stars is very dynamic. Many classes of stars show evidence for winds, disks, inflows and outflows with many phenomena occurring simultaneously. These processes are involved in stellar evolution,…
Most types of massive stars display X-ray emission that is affected by the properties of their stellar winds. Single non-magnetic OB stars have an X-ray luminosity that scales with their bolometric luminosity and their emission is thought…
Until now, HD 155448 has been known as a post-AGB star and listed as a quadruple system. In this paper, we study the system in depth and reveal that the B component itself is a binary and that the five stars HD 155448 A, B1, B2, C, and D…
Observations of magnetic fields of stars at the pre-main sequence phase can provide important new insights into the complex physics of the late stages of star formation. This is especially true at intermediate stellar masses, where magnetic…
We present the first high spatial and spectral observations of the circumstellar envelope (CSE) of a B[e] supergiant (CPD$-57 2874$), performed with the Very Large Telescope Interferometer (VLTI). Spectra, visibilities, and closure phase,…
B[e] Supergiants are a phase in the evolution of some massive stars for which we have observational evidence but no predictions by any stellar evolution model. The mass-loss during this phase creates a complex circumstellar environment with…
Be stars are a class of rapidly rotating B stars with circumstellar disks that cause Balmer and other line emission. There are three possible reasons for the rapid rotation of Be stars: they may have been born as rapid rotators, spun up by…
Be stars are B-type main-sequence stars that display broad Balmer emission lines in their spectra. Identification of Be population is essential to further examine the formation and evolutionary models. We report the detection of classical…
Polarization is an important indicator of stellar evolution, especially for stars evolving from red-giant stage to planetary nebulae. However, not much is known about the polarimetric properties of the carbon-enhanced metal-poor (CEMP)…
The infrared excess from OB stars are commonly considered as contributions from ionized stellar wind or circumstellar dust. With the newly published LAMOST-OB catalog and GOSSS data, this work steps further on understanding the infrared…
In the group of B stars with spectroscopic peculiarities, we can find the Be and the B[e] stars. The Be stars are early-type rapid rotators that present, as their principal characteristic, emission lines of hydrogen and singly ionized…
We present high-quality spectra of the majority of stars that have been classified as Oe and find that their published spectral types are generally too early, most likely due to infilling of HeI lines. As a matter of fact, all stars…