Related papers: MWC656: A Be+BH or a Be+sdO?
We use the self-consistent stellar populations in the Binary Population A Spectral Synthesis (BPASS) models to assess whether NGC1850-BH1 is a black hole. Using search criteria based on reported physical properties in the literature we…
W 601 (NGC 6611 601) is one of the handful of known magnetic Herbig Ae/Be stars. We report the analysis of a large dataset of high-resolution spectropolarimetry. The star is a previously unreported spectroscopic binary, consisting of 2 B2…
Bright Be star beta CMi has been identified as a non-radial pulsator on the basis of space photometry with the MOST satellite and also as a single-line spectroscopic binary with a period of 170.4 d. The purpose of this study is to…
From optical high-resolution spectra the nature of the unseen companion of HW Vir is determined without detection of any spectral features originating from the secondary itself. Using radial velocity measurements from the primary hot…
Spectroscopic monitoring of 141 southern field B type stars, 114 of them known to exhibit the Be phenomenon, allowed the estimation of their projected rotational velocities, effective temperatures and superficial gravities from…
About half of the hot subdwarfs are found to have spectra of composite types, indicating a main sequence companion of spectral type F-K, and the pulsators are no exception to this rule. The spectroscopic contamination from the main sequence…
Mennickent et al.and Sabogal et al.identified a large number of Classical Be (CBe) candidates in the L&SMC based on their photometric variability using the OGLEII database. They classified these stars into four different groups based on the…
3C186, a radio-loud quasar at $z=1.0685$, was previously reported to have both velocity and spatial offsets from its host galaxy, and has been considered as a promising candidate for a gravitational wave recoiling black hole triggered by a…
Rapid rotation and nonradial pulsations enable Be stars to build decretion disks, where the characteristic line emission forms. A major but unconstrained fraction of Be stars owe their rapid rotation to mass and angular-momentum transfer in…
If some or all Type Ia SNe arise from accretion onto a massive WD from a companion, then the companion will remain in some form after the SN explosion. Tycho-B is an unusual, relatively hot star along the line of sight to Tycho's SNR --…
Two scenarios have been proposed to match the existing observational constraints of the object HR 6819. The system could consist of a close inner B-type giant plus a black hole (BH) binary with an additional Be companion in a wide orbit.…
HR 6819 was recently proposed to be a triple system consisting of an inner B-type giant + black hole binary with an orbital period of 40d and an outer Be tertiary. This interpretation is mainly based on two inferences: that the emission…
We discuss photometric and spectroscopic data of the E/S0 galaxy NGC 4342, obtained with the Hubble Space Telescope (HST). This galaxy harbors, in addition to its outer disk, a very small, stellar disk in its nucleus. Jeans-modeling…
With its two stellar eclipses and two disk attenuations per binary orbit, V658 Carinae stands out as the first clear eclipsing Be + sdOB system. This rare alignment offers a unique opportunity to probe the structure and dynamics of a Be…
We estimate the mass of the compact object in the gamma-ray binaries LSI+61303 and MWC 148, using the latest data for the inclination, orbital motion and assuming that the orbital plane coincides with the equatorial plane of the Be star.…
We report the results of photometric monitoring of the Melotte 66 field in BVI filters. Ten variables were identified with nine being new discoveries. The sample includes eight eclipsing binaries of which four are W UMa type stars, one star…
A reliable determination of the basic physical properties and variability patterns of hot emission-line stars is important for understanding the Be phenomenon and ultimately, the evolutionary stage of Be stars. This study is devoted to one…
The subsolar mass primordial black hole (PBH) attracts attention as robust evidence of its primordial origin against the astrophysical black hole. Not only with themselves, PBHs can also form binaries with ordinary astrophysical objects,…
The emission-line binary ALS 8814 was recently proposed as a Be star + black hole (BH) binary based on large-amplitude radial velocity (RV) variations of a Be star and non-detection of spectroscopic features from a luminous companion. We…
The temperature structure of Be star circumstellar disks at the sub-solar metallicity appropriate to the Small Magellanic Cloud (SMC) is investigated. It is found that for central stars of the same spectral type, Be star disks in the SMC…