Related papers: High resolution spectroscopy of Ne II emission fro…
We present high spatial resolution (~ 35 parsec) 5-38 um spectra of the central region of M82, taken with the Spitzer Infrared Spectrograph. From these spectra we determined the fluxes and equivalent widths of key diagnostic features, such…
This paper is one in a series reporting results from small telescope observations of variable young stars. Here, we study the repeating outbursts of three likely Be stars based on long-term optical, near-infrared, and mid-infrared…
Early observations of T Tauri stars suggested that stars with evidence of circumstellar accretion disks rotated slower than stars without such evidence, but more recent results are not as clear. Near-IR circumstellar disk indicators, though…
The mid-infrared (mid-IR) wavelength regime offers several advantages for following the late-time evolution of supernovae (SNe). First, the peaks of the SN spectral energy distributions shift toward longer wavelengths following the…
Here we present the Spitzer IRS spectrum of CS Cha, a member of the ~2 Myr old Chamaeleon star-forming region, which reveals an optically thick circumstellar disk truncated at ~43 AU, the largest hole modeled in a transitional disk to date.…
Time-resolved IR spectroscopy of WZ Sge was obtained using NIRSPEC on Keck II. We detect CO and H$_{\rm 2}$ emission from the accretion disk placing WZ Sge into a rarefied class of astronomical objects including YSOs and high luminosity…
Investigating the outflows emanating from young stellar objects (YSOs) on sub-arcsecond scales provides important clues to the nature of the underlying accretion-ejection process occurring near the central protostar. We have investigated…
Fast outflows and their interaction with slow shells (generally known as the fossil circumstellar envelope of asymptotic giant branch stars) play an important role in the structure and kinematics of protoplanetary and planetary nebulae…
We report on spectro-imaging observations of the Herbig-Haro 2 outflow with the ISOCAM camera onboard the Infrared Space Observatory (ISO). The [Ne II}] 12.81 microns and [Ne III]15.55 microns lines are detected only towards the jet working…
Gas plays a major role in the dynamical evolution of young stellar objects. Its interaction with the dust is the key to our understanding planet formation later on in the protoplanetary disc stage. Studying the gas content is a crucial step…
Optical and near-infrared variability is a well-known property of young stellar objects. However, a growing number of recent studies claim that a considerable fraction of them also exhibit mid-infrared flux changes. With the aim of studying…
We present spatially resolved near-IR spectroscopic observations of 15 young stars. Using a grism spectrometer behind the Keck Interferometer, we obtained an angular resolution of a few milli-arcseconds and a spectral resolution of 230,…
We report new Spitzer observations of intermediate mass stars in two regions of the Orion OB1 association located in the subassociations OB1a ($\sim$10 Myr) and OB1b ($\sim$5 Myr). In a representative sample of stars earlier than F5 of both…
We report the detection of a broad 22 microns emission feature in the Carina nebula H II region by the Infrared Space Observatory (ISO) Short Wavelength Spectrometer. The feature shape is similar to that of the 22 microns emission feature…
High-quality K-band spectra of strongly reddened point sources, deeply embedded in (ultra-) compact HII regions, have revealed a population of 20 young massive stars showing no photospheric absorption lines, but sometimes strong Br-gamma…
Strong nebular emission lines are a sensitive probe of star formation and extinction in galaxies, and the [O II] line detects star forming populations out to z>1. However, star formation rates from emission lines depend on calibration of…
Most of the mass in protoplanetary disks is in the form of gas. The study of the gas and its diagnostics is of fundamental importance in order to achieve a detailed description of the thermal and chemical structure of the disk. The…
High-quality K-band spectra of point sources, deeply embedded in massive star-forming regions, have revealed a population of 20 young massive stars showing no photospheric absorption lines, but only emission lines. The K-band spectra…
We aim to characterize the distribution and composition of circumstellar material around young massive stars, and to investigate exactly which physical structures in these objects are probed by long-baseline mid-infrared interferometric…
We present the results of ground-based imaging spectroscopy of the [Ne II] 12.8 micron line emitted from the ultracompact (UC) H II regions; W51d, G45.12+0.13, G35.20-1.74 and Monoceros R2, with 2arcsec spatial resolution. We found that the…