Related papers: Time-Variable Accretion in the TW Hya Star/Disk Sy…

The results of spectroscopic and photometric monitoring of the classical T Tauri star RY Tau are presented. The observation series span 220 nights from 2013 to 2024. During the observation period, the star's brightness varied within the…

EX Hya is one of the best studied, but still enigmatic intermediate polars. We present phase-resolved blue VLT/UVES high-resolution ($\lambda/\Delta \lambda\simeq16.000$) spectra of EX Hya taken in January 2004. Our analysis involves a…

Classical T Tauri stars (CTTS) are surrounded by actively accreting disks. According to current models material falls along the magnetic field lines from the disk with more or less free-fall velocity onto the star, where the plasma heats up…

We present an analysis of the 2011 photometric observations of TW Hya by the MOST satellite; this is the fourth continuous series of this type. The large-scale light variations are dominated by a strong, quasi-periodic 4.18 d oscillation…

We observe a significant change in the TW Hya disk interior to 40~AU via archival unpolarized multi-wavelength Hubble Space Telescope/STIS and NICMOS images with an inner working angle (IWA) of 0\farcs4 (22~AU). Our images show the outer…

We present Keck Interferometer observations of TW Hya that spatially resolve its emission at 2 micron wavelength. Analyzing these data together with existing K-band veiling and near-infrared photometric measurements, we conclude that the…

We present self-consistent models of gas in optically-thick dusty disks and calculate its thermal, density and chemical structure. The models focus on an accurate treatment of the upper layers where line emission originates, and at radii…

We report the first comprehensive study of emission line variability in an accreting young brown dwarf. We have collected 14 high-resolution optical spectra of 2MASSW J1207334-393254 (M8), a likely member of the nearby 8-million-year-old TW…

TWA 27B (2M1207b) is the first directly-imaged planetary-mass (MP ~ 5 MJ) companion (Chauvin et al. 2004) and was observed at 0.9--5.3 micron with JWST/NIRSpec (Luhman et al. 2023). To understand the accretion properties of TWA 27B, we…

At 60 pc, TW Hydra (TW Hya) is the closest example of a star with a gas-rich protoplanetary disk, though TW Hya may be relatively old (3-15 Myr). As such, TW Hya is especially appealing to test our understanding of the interplay between…

We present our second paper describing multi-wave-band, time-resolved spectroscopy of WZ Sge. We analyze the evolution of both optical and IR emission lines throughout the orbital period and find evidence, in the Balmer lines, for an…

We report two-dimensional spectroastrometry of Br gamma emission of TW Hya to study the kinematics of the ionized gas in the star-disk interface region. The spectroastrometry with the integral field spectrograph SINFONI at the Very Large…

We have obtained a series of high-resolution optical spectra for the brown dwarf 2MASSW J1207334-393254 (2M1207) using the ESO Very Large Telescope with the UVES spectrograph during two consecutive observing nights (time resolution of ~12…

The accretion/ejection processes in T-Tauri stars are fundamental to their physical evolution, while also impacting the properties and evolution of the circumstellar material at a time when planet formation takes place. To this date,…

We present ALMA Cycle~2 observations at $0.5^{\prime\prime}$ resolution of TW Hya of CS $J=5-4$ emission. The radial profile of the integrated line emission displays oscillatory features outwards of $1.5^{\prime\prime}$ ($\approx 90$ au). A…

We present new observations of CO J=2-1 emission from the protoplanetary disk around TW Hya. Emission is detected out to 240 au (4") and found to exhibit azimuthal variations up to 20% beyond 180 au (3"), with the west side of the disk…

We have developed a self-consistent model of the disk around the nearby 10 Myr old star TW Hya which matches the observed spectral energy distribution and 7mm images of the disk. The model requires a significant dust size evolution and a…

We compare line emission calculated from theoretical disk models with optical to sub-millimeter wavelength observational data of the gas disk surrounding TW Hya and infer the spatial distribution of mass in the gas disk. The model disk that…

(Abridged) High-resolution spectroscopic monitoring of RW Aur A was carried out in 1996, 1998 and 1999 with simultaneous B, V photometry. A multicomponent spectrum is revealed with a veiled photospheric spectrum, broad emissions, narrow…

We report here results of spectropolarimetric observations of the ~8Myr classical TTauri star (cTTS) TWHya carried out with ESPaDOnS at the Canada-France-Hawaii Telescope (CFHT) in the framework of the `Magnetic Protostars and Planets'…