Related papers: Investigating three Sirius-like systems with SPHER…
Abridged: We report the discovery of two, new, rare, wide, double-degenerate binaries that each contain a magnetic and a non-magnetic star. The components of SDSSJ092646.88+132134.5 + J092647.00+132138.4 and SDSSJ150746.48+521002.1 +…
We performed a chemical analysis of the asteroid-bearing white dwarf WD 1145+017 using optical and ultraviolet spectroscopic data from 25 epochs between 2015 and 2023. We present an updated gas disk model with improved opacity calculations…
Evolved low- to intermediate-mass stars are known to shed their gaseous envelope into a large, dusty, molecule-rich circumstellar nebula which typically develops a high degree of structural complexity. Most of the large-scale, spatially…
We present high-resolution spectroscopy of two nearby white dwarfs with inconsistent spectroscopic and parallax distances. The first one, PG 1632+177, is a 13th magnitude white dwarf only 25.6 pc away. Previous spectroscopic observations…
We image with unprecedented spatial resolution and sensitivity disk features that could be potential signs of planet-disk interaction. Two companion candidates have been claimed in the disk around the young Herbig Ae/Be star HD100546. Thus,…
Monitoring the long-term radial velocity (RV) and acceleration of nearby stars has proven an effective method for directly detecting binary and substellar companions. Some fraction of nearby RV trend systems are expected to be comprised of…
Radio pulsating white dwarf (WD) systems, known as WD pulsars, are non-accreting binary systems where the rapidly spinning WD interacts with a low-mass companion producing pulsed non-thermal emission that can be observed across the entire…
Aims: We aim to characterize the physical and morphological properties of the binary system AFGL 4106, composed of two evolved massive stars. Understanding its mass-loss processes and circumstellar environment offers insight into the late…
Beyond the main sequence solar type stars undergo extensive mass loss, providing an environment where planet and brown dwarf companions interact with the surrounding material. To examine the interaction of substellar mass objects embedded…
We report high-resolution spectroscopic observations of WD 1145+017 -- a white dwarf that recently has been found to be transitted by multiple asteroid-sized objects within its tidal radius. We have discovered numerous circumstellar…
As the descendants of stars with masses less than 8 M$_{\odot}$ on the main sequence, white dwarfs provide a unique way to constrain planetary occurrence around intermediate-mass stars (spectral types BAF) that are otherwise difficult to…
S stars are late-type giants with overabundances of s-process elements. They come in two flavours depending on the presence or not of technetium (Tc), an element without stable isotopes. Intrinsic S stars are Tc-rich and genuine asymptotic…
SDSSJ125733.63+542850.5 (hereafter SDSSJ1257+5428) is a compact white dwarf binary from the Sloan Digital Sky Survey that exhibits high-amplitude radial velocity variations on a period of 4.56 hours. While an initial analysis suggested the…
The nearby Sun-like star HD 114174 exhibits a strong and persistent Doppler acceleration indicating the presence of an unseen distant companion. We have acquired high-contrast imaging observations of this star using NIRC2 at Keck and report…
Using newly obtained high-resolution data ($R\sim{1\times{10}^{5}}$) from the \textit{Hubble Space Telescope}, and archival UV data from the \textit{Far Ultraviolet Spectroscopic Explorer} we have conducted a detailed UV survey of the three…
A recent cross-correlation between the SDSS DR7 White Dwarf Catalog with the Wide-Field Infrared Survey Explorer ($WISE$) all-sky photometry at 3.4, 4.6, 12, and 22 microns performed by Debes et al. (2011) resulted in the discovery of 52…
White dwarfs (WD) with main-sequence (MS) companions are crucial probes of stellar evolution. However, due to the significant difference in their luminosities, the WD is often outshined by the MS star. The aim of this work is to find hidden…
We present a new model atmosphere analysis of the most metal contaminated white dwarf known, the DBZ SDSS J073842.56+183509.06. Using new high resolution spectroscopic observations taken with Keck and Magellan, we determine precise…
Study of primary stars lying in Sirius-like systems with various masses of WD companions and orbital separations is one of the key aspects to understand the origin and nature of Barium (Ba) stars. In this paper, based on high resolution and…
The White Dwarf Binary Pathways Survey aims at increasing the number of known detached A, F, G and K main sequence stars in close orbits with white dwarf companions (WD+AFGK binaries) to refine our understanding about compact binary…