Related papers: Dynamical masses of the low-mass stellar binary AB…

We expand upon the results of Close et al. 2005 regarding the young, low-mass object AB Dor C and its role as a calibration point for theoretical tracks. We present an improved spectral reduction and a new orbital solution with two…

We observe 14 young low-mass substellar objects in young moving groups using the SINFONI IFS with LGS-AO to detect and characterize 3 candidate binary systems. Together with the adopted young moving group ages we employ isochrones from…

The Pleiades is a young open cluster that has not yet dynamically relaxed, making it an ideal target to observe various internal dynamical effects. By employing a well-defined sample of main-sequence (MS) cluster members, including both MS…

Observations of binaries have traditionally provided the means for ascertaining stellar masses. Here, we use the published data on 8 pre-main-sequence pairs to gauge the accuracy of our own, recently calculated, evolutionary tracks (Palla &…

We present results from the B-type Binaries Characterisation (BBC) programme, a multi-epoch spectroscopic study of 88 early B-type binary candidates in the 30 Doradus region of the Large Magellanic Cloud (LMC). From radial-velocity analysis…

We combine new Lucky Imaging astrometry from NTT/AstraLux Sur with already published astrometry from the AstraLux Large M-dwarf Multiplicity Survey to compute orbital elements and individual masses of the 2MASS J10364483+1521394 triple…

Young M-type binaries are particularly useful for precise isochronal dating by taking advantage of their extended pre-main sequence evolution. Orbital monitoring of these low-mass objects becomes essential in constraining their fundamental…

We present recent measurements of the orbital motion in the binaries, DF Tau and ZZ Tau, and in the triples, Elias 12, T Tau, and V853 Oph. We observed these systems with the Fine Guidance Sensors on the Hubble Space Telescope and with…

Astrometric observations of resolved binaries provide estimates of orbital periods and will eventually lead to measurement of dynamical masses. Only a few very low mass star and brown dwarf masses have been measured to date, and the…

We report on nine wide common proper motion systems containing late-type M, L, or T companions. We confirm six previously reported companions, and identify three new systems. The ages of these systems are determined using diagnostics for…

Because many classical Be stars may owe their nature to mass and angular-momentum transfer in a close binary, the present masses, temperatures, and radii of their components are of high interest for comparison to stellar evolution models.…

Orbital motion in binary and planetary systems is the main source of precise stellar and planetary mass measurements, and joint analysis of data from multiple observational methods can both lift degeneracies and improve precision. We set…

LP~349$-$25 is a well studied close stellar binary system comprised of two late M dwarf stars, both stars close to the limit between star and brown dwarf. This system was previously identified as a source of GHz radio emission. We observed…

We report the discovery of a substellar-mass co-moving companion to 2MASS J22501512+2325342, an M3 candidate member of the young (130--200 Myr) AB Doradus Moving Group (ABDMG). This L3 beta companion was discovered in a 2MASS search for…

Using speckle-interferometry we have carried out repeated measurements of relative positions for the components of 34 T Tauri binary systems. The projected separation of these components is low enough that orbital motion is expected to be…

Evolutionary models are widely used to infer the mass of stars, brown dwarfs, and giant planets. Their predictions are thought to be less reliable at young ages ($<$ 200 Myr) and in the low-mass regime ($\mathrm{<1~M_{\odot}}$). GJ 2060 AB…

We present Keck/NIRC2 and OSIRIS near-infrared imaging and spectroscopy of 2M0441+2301 AabBab, a young (1--3 Myr) hierarchical quadruple system comprising a low-mass star, two brown dwarfs, and a planetary-mass companion in Taurus. All four…

We report individual dynamical masses of $66.92 \pm 0.36 \; M_{Jup}$ and $53.25 \pm 0.29 \; M_{Jup}$ for the binary brown dwarfs $\varepsilon$ Indi Ba and Bb, measured from long term ($\approx 10$ yr) relative orbit monitoring and absolute…

The full two-body problem (F2BP) is often used to model binary asteroid systems, representing the bodies as two finite mass distributions whose dynamics are influenced by their mutual gravity potential. The emergent behavior of the F2BP is…

We measure precise orbits and dynamical masses and derive age constraints for six confirmed and one candidate Sirius-like systems, including the Hyades member HD 27483. Our orbital analysis incorporates radial velocities, relative…