Related papers: The quadruple pre-main sequence system LkCa3: Impl…
Context. In multiple pre-main-sequence systems the lifetime of circumstellar disks appears to be shorter than around single stars, and the actual dissipation process may depend on the binary parameters of the systems. Aims. We report high…
We present a drift scan survey covering a ~5 deg by 50 deg region toward the southern portion of the Taurus-Auriga molecular cloud. Data taken in the B,R,I filters with the Quest-2 camera on the Palomar 48-inch telescope were combined with…
We present results from our ongoing program to map the visual orbits of pre-main sequence binaries in the Taurus star forming region using adaptive optics imaging at the Keck Observatory. We combine our results with measurements reported in…
II UMa is a late F-type (F5) contact binary with a close-in tertiary and a distant visual companion. According to the four-color ($B$ $V$ $R_c$ $I_c$) light curves' solutions of II UMa, it is a high fill-out (f=$86.6\,\%$) and low mass…
We have discovered a compact hierarchical triple main-sequence star system, which is cataloged as Gaia DR3 1010268155897156864 or TIC 21502513. Hereafter, we call it ``G1010''. G1010 consists of a primary (the most massive) star and inner…
AR Aur is a detached eclipsing binary containing two late-B stars which are chemically peculiar, on a circular orbit of period 4.135 d. The primary is a HgMn star which shows temporal changes in its chemical abundances and spectral line…
We present a comprehensive photometric and spectroscopic analysis of the Algol-type binary \textit{Gaia} DR3 1892576067672499328. We identified the system as a spectroscopic binary based on medium-resolution LAMOST spectra. Combined with…
We report new multi-colour photometry and high-resolution spectroscopic observations of the long-period variable V501 Aur, previously considered to be a weak-lined T-Tauri star belonging to the Taurus-Auriga star-forming region. The…
One of the most effective ways to test stellar evolutionary models is to measure dynamical masses for binary systems at a range of temperatures. In this paper, we present orbits of three young K+M binary systems in Taurus (Hubble~4, FF~Tau,…
Hierarchical massive quadruple systems are ideal laboratories for examining the theories of star formation, dynamical evolution, and stellar evolution. The successive mergers of hierarchical quadruple systems might explain the mass gap…
We present new orbital measurements of the pre-main sequence triple system, V807 Tau, using adaptive optics imaging at the Keck Observatory. We computed an orbit for the close pair, V807 Tau Ba-Bb, with a period of 12.312 +/- 0.058 years…
The projected stellar rotational velocity ($v \sin i$) is critical for our understanding of processes related to the evolution of angular momentum in pre-main sequence stars. We present $v \sin i$ measurements of high-resolution infrared…
Recent sub-millimetric observations at the Plateau de Bure interferometer evidenced a cavity at ~ 46 AU in radius into the proto-planetary disk around the T Tauri star LkCa15 (V1079 Tau), located in the Taurus molecular cloud. Additional…
We report extensive radial-velocity measurements of the two giant components of the detached, 104-day period binary system of Capella. Our highly accurate three-dimensional orbital solution based on all existing spectroscopic and…
We report on interferometric and radial-velocity observations of the double-lined 51-d period binary (A) component of the quadruple pre-main sequence (PMS) system V773 Tau. With these observations we have estimated preliminary visual and…
We report the results of a spectroscopic survey of 20 close T Tauri binaries in the Taurus-Auriga dark cloud where the separations between primaries and their secondaries are less than the typical size of a circumstellar disk around a young…
This paper describes a systematic search for high-order multiplicity among wide visual Pre-Main Sequence (PMS) binaries. We conducted an Adaptive Optics survey of a sample of 58 PMS wide binaries from various star-forming regions, which…
We present the identification of two previously known young objects in the solar neighbourhood as a likely very wide binary. TYC 9486-927-1, an active, rapidly rotating early-M dwarf, and 2MASS J21265040-8140293, a low-gravity L3 dwarf…
We have analyzed photometric and spectroscopic data of a sample of 14 spatially resolved pre-main-sequence binaries (separations 0.6" to 1.7") in the nearby (150 pc) low-mass star-forming regions of Chamaeleon, Lupus, and rho Ophiuchi. The…
The first V Rc Ic bands light curves of MQ UMa are presented and analyzed using the Wilson-Devinney (W-D) program. It is discovered that MQ UMa is an A-subtype contact binary with a high fill-out (f=82 %) and a low mass ratio (q = 0:195),…