Related papers: Massive Star Multiplicity: The Cepheid W Sgr
We report the results of a CGRO 3-week observation of the binary system containing the 47 ms pulsar PSR B1259-63 orbiting around a Be star companion in a very eccentric orbit. The PSR B1259-63 binary is a unique system for the study of the…
We have made {\it XMM-Newton\/} observations of 14 Galactic Cepheids that have candidate resolved ($\geq$5$\arcsec$) companion stars based on our earlier {\it HST\/} WFC3 imaging survey. Main-sequence stars that are young enough to be…
We present high resolution spectro-astrometry of a sample of 28 Herbig Ae/Be and 3 F-type pre-main sequence stars. The spectro-astrometry is shown from both empirical and simulated data to be capable of detecting binary companions that are…
CONTEXT. Many O-type stars have nearby companions whose presence hamper their characterization through spectroscopy. AIMS. We want to obtain spatially resolved spectroscopy of close O-type visual binaries to derive their spectral types.…
In this paper we present the results of the SPHERE observation of the HD 284149 system, aimed at a more detailed characterisation of both the primary and its brown dwarf companion. We observed HD 284149 in the near-infrared with SPHERE,…
Ultraviolet spectra were taken of 25 Detached Eclipsing Binaries (DEBs) with spectral types O, B, and early A with the International Ultraviolet Explorer (IUE) satellite in the 1150 to 1900 ${\AA}$ region. The spectra were compared with…
The multiple star system of delta Orionis is one of the closest examples of a system containing a luminous O-type, bright giant star (component Aa1). It is often used as a spectral-type standard and has the highest observed X-ray flux of…
We report the discovery of a hot white dwarf (WD) companion to a blue straggler star (BSS) in the globular cluster (GC) NGC 5466, based on observations from the Ultra-Violet Imaging Telescope (UVIT) on board AstroSat. The Spectral Energy…
We report the first look at extragalactic Cepheid variables with the James Webb Space Telescope, obtained from a serendipitous (to this purpose) observation of NGC 1365, host of an SN Ia (SN 2012fr), a calibration path used to measure the…
Binary/multiple status can affect stars at all stages of their lifetimes: evolution onto the main sequence, properties on the main sequence, and subsequent evolution. 5 $M_\odot$ stars have provided a wealth of information about the binary…
We present new transit observations of the hot Jupiter WASP-74 b ($T_\mathrm{eq} \sim$ 1860 K) using the high-resolution spectrograph HARPS-N and the multi-colour simultaneous imager MuSCAT2. We refine the orbital properties of the planet…
Close binary interactions may play a critical role in the formation of the rapidly rotating Be stars. Mass transfer can result in a mass gainer star spun up by the accretion of mass and angular momentum, while the mass donor is stripped of…
We present Kepler and Swift observations of StHa 169 which is currently classified as a symbiotic binary. The Kepler light curve shows quasi periodic behaviour with a mean period of 34 d and an amplitude of a few percent. Using Swift data…
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…
In this paper we present our results of a comprehensive spectroscopicanalysis of WASP-1, the host star to the exoplanet WASP-1b. We derive T_eff = 6110 +/- 45 K, log g = 4.28 +/- 0.15, and [M/H] = 0.23 +/- 0.08, and also a high abundance of…
We study the multiplicity of host stars to known transiting extra-solar planets to test competing theories on the formation mechanisms of hot Jupiters. We observed 45 exoplanet host stars using VLT/SPHERE/IRDIS to search for potential…
We present the results of a high-resolution imaging survey of 12 brown dwarfs and very low mass stars in the closest (~145 pc) young (~5 Myr) OB association, Upper Scorpius. We obtained images with the Advanced Camera for Surveys/High…
Alpha Crucis is the closest very high multiplicity massive star to the Sun. At its heart is the $4" \leftrightarrow 430 \text{ au}$ binary $\alpha^1$ (A) + $\alpha^2$ (B) Cru, which combined make up the 13th visually brightest star in the…
We have used the 2MASS all-sky survey and the WISE to look for ultracool dwarfs that are part of multiple systems containing main sequence stars. We cross-matched L dwarf candidates from the surveys with Hipparcos and Gliese stars, finding…
We identified a sample of 88 bona fide Population II Cepheids (henceforth referred to as Cepheids) and 44 candidates in Galactic globular clusters (GCs). Seventy-eight of the Cepheids in the sample align within $2\,\sigma$ of the…