Related papers: Resolving the delta Andromedae spectroscopic binar…
Sun-like stars are promising candidates to host exoplanets and are often included in exoplanet surveys by radial velocity (RV) and direct imaging. In this paper we report on the detection of a stellar companion to the nearby solar-analogue…
We find that $\sim 15-20$ per cent of A-type stars or red giants are bound with a massive companion ($M_{\rm secondary} > 1M_{\odot}$) in an intermediate wide orbit ($0.5<P<5000\mbox{ yr}$). These massive binaries are expected to form…
Many problems in contemporary astrophysics---from understanding the formation of black holes to untangling the chemical evolution of galaxies---rely on knowledge about binary stars. This, in turn, depends on discovery and characterization…
We report detection of the binary companion to the millisecond pulsar J2302+4442 based on the deep observations performed with the Gran Telescopio Canarias. The observations revealed an optical source with $r'$ = 23.33$\pm$0.02 and…
We present the results of a speckle interferometric survey of Galactic massive stars that complements and expands upon a similar survey made over a decade ago. The speckle observations were made with the KPNO and CTIO 4 m telescopes and…
We report techniques and results of a Palomar 200-inch (5 m) adaptive optics imaging survey of sub-stellar companions to solar-type stars. The survey consists of Ks coronagraphic observations of 21 FGK dwarfs out to 20 pc (median distance…
We investigate the temporal spot evolution of the K-giant component in the RS CVn-type binary system $\zeta$\,Andromedae to establish its surface differential rotation. Doppler imaging is used to study three slightly overlapping…
Nearby stars offer prime opportunities for exoplanet discovery and characterization through various detection methods. By combining HCI, RV, and astrometry, it is possible to better constrain the presence of substellar companions, as each…
Astrometric measurements are presented for seven nearby stars with previously detected planets: six M dwarfs (GJ 317, GJ 667C, GJ 581, GJ 849, GJ 876, and GJ 1214) and one K dwarf (BD $-$10 3166). Measurements are also presented for six…
Symbiotic systems are interacting binary stars consisting of both hot and cool components. This results in a complex environment that is ideal for studying the latter stages of stellar evolution along with interactions within binary…
The evolution of starspots of the giant primaries of RS CVn systems is typically detected indirectly with photometric and spectroscopic monitoring. These observations suggest slowly-evolving stellar surfaces and can constrain differential…
The unparalleled photometric data obtained by NASA's Kepler Space Telescope has led to improved understanding of red-giant stars and binary stars. We discuss the characterization of known eccentric system, containing a solar-like…
The masses of compact objects like white dwarfs, neutron stars and black holes are fundamental to astrophysics, but very difficult to measure. We present the results of an analysis of subluminous B (sdB) stars in close binary systems with…
The number of spatially unresolved white dwarf plus main-sequence star binaries has increased rapidly in the last decade, jumping from only ~30 in 2003 to over 3000. However, in the majority of known systems the companion to the white dwarf…
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…
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 the unplanned detection of a white dwarf companion to the star HD 218261 in mid-infrared (10-16 $\mu$m) observations with JWST/MIRI. This star was observed as a calibrator for coronagraphic observations of the exoplanet host HR…
A subset of 51 Hipparcos astrometric binaries among FG dwarfs within 67pc has been surveyed with the NICI adaptive optics system at Gemini-S, directly resolving for the first time 17 sub-arcsecond companions and 7 wider ones. Using these…
We report the results from a pilot study to search for black holes and other dark companions in binary systems using direct imaging with SHARK-VIS and the iLocater pathfinder "Lili" on the Large Binocular Telescope. Starting from known…
We present near-infrared magnitudes for all white dwarfs (selected from the catalog of McCook & Sion) contained in the 2 Micron All Sky Survey Second Incremental Data Release(2MASS 2IDR). We show that the near-IR color-color diagram is an…