Related papers: Classifying the secondary component of the binary …
A study is made of a sample of 58 dust-enshrouded Asymptotic Giant Branch (AGB) stars (including 2 possible post AGB stars), of which 27 are carbon-rich and 31 are oxygen-rich. These objects were originally identified by Jura & Kleinmann as…
The observations and comprehensive study of intermediate initial mass stars at the late stages of evolution, and after the asymptotic giant branch (AGB) in particular, are of crucial importance to identify the common properties for the…
If recurrent novae are progenitors of Type Ia supernovae, their white dwarfs must have masses close to the Chandrasekhar limit. The most reliable means of determining white dwarf masses in recurrent novae is dynamically, via radial-velocity…
B[\,e\,] supergiants are a rare and unusual class of massive and luminous stars, characterised by opaque circumstellar envelopes. GG Carinae is a binary whose primary component is a B[\,e\,] supergiant and whose variability has remained…
We report the detection of a very low mass star (VLMS) companion to the primary star 1SWASPJ234318.41+295556.5A (J2343+29A), using radial velocity (RV) measurements from the PARAS (PRL Advanced Radial-velocity Abu-sky Search) high…
We present new theoretical stellar yields and surface abundances for asymptotic giant branch (AGB) models with a metallicity appropriate for stars in the Small Magellanic Cloud (SMC, $Z= 0.0028$, [Fe/H] $\approx -0.7$). New evolutionary…
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…
Observations of the outflows of asymptotic giant branch (AGB) stars continue to reveal their chemical and dynamical complexity. Spherical asymmetries, such as spirals and disks, are prevalent and thought to be caused by binary interaction…
We present the first results of our ongoing chemical study of carbon stars in the Local Group of galaxies. We used spectra obtained with UVES at the 8.2 m Kueyen-VLT telescope and a new grid of spherical model atmospheres for cool…
There is a striking and unexplained dearth of brown dwarf companions in close orbits (< 3AU) around stars more massive than the Sun, in stark contrast to the frequency of stellar and planetary companions. Although rare and relatively…
The transition from the Asymptotic Giant Branch (AGB) to the planetary nebula (PN) phase is critical in the shaping of PNe. It is suggested that the most asymmetric PNe are the descendant of massive AGB stars. Since these AGB stars are…
We present deep Chandra observations of PSO J231.6576$-$20.8335, a quasar at redshift z=6.59 with a nearby (${\sim}8$ proper kpc) companion galaxy. ALMA observed both the quasar and companion to be bright in [C II], and the system has…
We introduce a binary classification model, {\it the Double Filter Model}, utilizing various machine learning and deep learning methods to classify Young Stellar Objects (YSOs) and Asymptotic Giant Branch (AGB) stars. Since YSOs and AGB…
The literature is rich in analysis and results related to thermally pulsing-asymptotic giant branch (TP-AGB) stars, but the problem of the instabilities that arise and cause the divergence of models during the late stages of their evolution…
The eclipsing binary LL Aqr consists of two late-type stars in an eccentric orbit with a period of 20.17 d. We use an extensive light curve from the SuperWASP survey augmented by published radial velocities and UBV light curves to measure…
Multiple stellar populations (MPs) are a distinct characteristic of Globular Clusters (GCs). Their general properties have been widely studied among main sequence, red giant branch (RGB) and horizontal branch (HB) stars, but a common…
We present visible polarimetric imaging observations of the well-studied AGB star W Hya taken with VLT/SPHERE-ZIMPOL as well as high spectral resolution long-baseline interferometric observations with the AMBER instrument of the Very Large…
Stars with masses between roughly 1 and 8~$M_\odot$ end their lives on the asymptotic giant branch (AGB), when intense mass loss takes place. The outflows are generally accepted to be driven by radiation pressure acting on dust grains that…
Recent ALMA observations indicate that CW Leo, the closest carbon-rich AGB star to the Sun, might have a low-mass stellar companion. We present archival ground-based astrometric measurements of CW Leo obtained within the context of the…
We have found the central star of Abell 70 (PN G038.1-25.4, hereafter A 70) to be a binary consisting of a G8 IV-V secondary and a hot white dwarf. The secondary shows enhanced Ba II and Sr II features, firmly classifying it as a barium…