Related papers: High-resolution Spectroscopy of [Ne II] Emission f…

We present infrared (IR) and optical echelle spectra of the Classical T Tauri star TW Hydrae. Using the optical data, we perform detailed spectrum synthesis to fit atomic and molecular absorption lines and determine key stellar parameters:…

We present a first emission line analysis of a high resolution X-ray spectrum of the stellar wind of theta 1 Ori C obtained with the High Energy Transmission grating Spectrometer onboard the Chandra X-ray Observatory. The spectra are…

Classical T Tauri stars show a plethora of in- and outflow signatures in a variety of wavelengths bands. In order to constrain gas velocities and temperatures we analyse the emission in the hot ion lines. We use all available archival FUSE…

We present high-contrast imaging data on the disk of the classical T Tauri star TW Hya. The images were obtained through the polarimetric differential imaging technique with the adaptive optics system NACO. Our commissioning data show the…

We want to improve knowledge of the structure of the inner few AU of the circumstellar disk around the nearby T Tauri star TW Hya. Earlier studies have suggested the existence of a large inner hole, possibly caused by interactions with a…

We present high spectral resolution ($R\approx108,000$) Stokes $V$ polarimetry of the Classical T Tauri stars (CTTSs) GQ Lup and TW Hya obtained with the polarimetric upgrade to the HARPS spectrometer on the ESO 3.6 m telescope. We present…

We analyze the far-ultraviolet (FUV) spectra of 33 classical T Tauri stars (CTTS), including 20 new spectra obtained with the Advanced Camera for Surveys Solar Blind Channel (ACS/SBC) on the Hubble Space Telescope. Of the sources, 28 are in…

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 report the discovery of quiescent emission from molecular hydrogen gas located in the circumstellar disks of six pre-main sequence stars, including two weak-line T Tauri stars (TTS), and one Herbig AeBe star, in the Chamaeleon I star…

We report on the analysis of high resolution X-ray spectra of two pre-main-sequence stars: TWA 5 (observed with XMM-Newton) and PZ Telescopii (observed with Chandra/HETGS). TWA 5 is a classical T Tauri star in the TW Hydrae association…

We present the results of an analysis of ultraviolet observations of T Tauri Stars (TTS). By analysing emission measures taken from the literature we derive rates of ionizing photons from the chromospheres of 5 classical TTS in the range…

We detect near-infrared H2 emission in DG Tau using the Infrared Camera and Spectrograph (IRCS) on the 8.2-m SUBARU telescope. The spectra obtained along the jet axis show that the centroidal position of the 1-0 S(1) emission is offset by…

We present detailed geometry and kinematics of the inner outflow toward HL Tau observed using Near Infrared Integral Field Spectograph (NIFS) at the Gemini-North 8-m Observatory. We analyzed H2 2.122 um emission and [Fe II] 1.644 um line…

We survey fluorescent H2 emission in HST/STIS spectra of the classical T Tauri stars (CTTSs) TW Hya, DF Tau, RU Lupi, T Tau, and DG Tau, and the weak-lined T Tauri star (WTTS) V836 Tau. From each of those sources we detect between 41-209…

High-energy radiation from T Tauri stars (TTS) influences the amount and longevity of gas in disks, thereby playing a crucial role in the creation of gas giant planets. Here we probe the high-energy ionizing radiation from TTS using…

We present the high resolution spectra of the youn and compact planerary nebula NGC 6790 obtained with the echelle spectrograph at Bohyunsan Optical Astronomy Observatory and report the discovery of Raman scattered He II 6545 in this…

Our knowledge of circumstellar disks has traditionally been based on studies of dust. However, gas dominates the disk mass and its study is key to understand the star and planet formation process. Spitzer can access gas emission lines in…

We present VLA and PdBI subarcsecond images (0.15"-0.6") of the radiocontinuum emission at 7 mm and of the SO2 J=19_{2,18}-18_{3,15} and J=27_{8,20}-28_{7,21} lines toward the Cepheus A HW2 region. The SO2 images reveal the presence of a…

We report the detection of quiescent H2 emission in a spatially resolved ring-like structure within 100 AU of T Tau N. We present evidence to show that the emission most likely arises from shocks in the atmosphere of a nearly face-on disk…

We describe the TEXES survey for mid-IR H2 pure rotational emission from young stars and report early successes. H2 emission is a potential tracer of warm gas in circumstellar disks. Three pure rotational lines are available from the…