Related papers: A slowly accreting ~10 Myr old transitional disk i…

We present Spitzer Infrared Spectrograph spectra of 28 Class I protostars in the Taurus star-forming region. The 5 to 36 micron spectra reveal excess emission from the inner regions of the envelope and accretion disk surrounding these…

We present high-quality, medium resolution X-shooter/VLT spectra in the range 300-2500 nm for a sample of 12 very low-mass stars in the \sigma Orionis cluster. The sample includes stars with masses ranging from 0.08 to 0.3 M$_\odot$. The…

We present new KPNO 0.9-m optical and VLA HI spectral line observations of the Orion dwarf galaxy. This nearby (D ~ 5.4 Mpc), intermediate-mass (M_dyn = 1.1x10^10 Solar masses) dwarf displays a wealth of structure in its neutral ISM,…

We present high resolution adaptive optics (AO) corrected images of the silhouette disk Orion 218-354 taken with Magellan AO (MagAO) and its visible light camera, VisAO, in simultaneous differential imaging (SDI) mode at H-alpha. This is…

Source I in the Orion-KL nebula is believed to be the nearest example of a massive star still in the main accretion phase. It is thus one of the best cases for studying the properties of massive protostars to constrain high-mass star…

High spectral and spatial resolution observations of the HCO+ molecule toward the T Tau binary system obtained with the Owens Valley Millimeter Array reveal a broad emission line profile (V_LSR = 7.2 km/s, width = 2.0 km/s) upon which a…

We present initial results from a survey of the Orion A and B molecular clouds made with the InfraRed Array Camera (IRAC) onboard the Spitzer Space Telescope. This survey encompasses a total of 5.6 square degrees with the sensitivity to…

We present 5-35 $\mu$m spectra, taken with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope, of five FU Orionis objects: FU Ori, V1515 Cyg, V1057 Cyg, BBW 76, and V346 Nor. All but V346 Nor reveal amorphous silicate grains in…

VLT/FORS spectroscopy and 2MASS near-infrared photometry, together with previously known data, have been used to establish the membership and the properties of a sample of low-mass candidate members of the sigma Orionis cluster with masses…

We present high resolution (R=55,000) optical spectra obtained with MIKE on the 6.5 m Magellan Clay Telescope as well as Spitzer MIPS photometry and IRS low resolution (R~60) spectroscopy of the close (14 AU separation) binary, HD 101088, a…

(Note: this is a shortened version of the original "structured" A&A format abstract.) We performed a large optical spectroscopic and photometric survey of the Lynds~1630N and 1641 clouds. We provide a catalog of 132 confirmed young stars in…

We report here on the photometric and kinematic properties of a well defined group of nearly 200 low-mass pre-main sequence stars, concentrated within ~ 1 deg of the early-B star 25 Ori, in the Orion OB1a sub-association. We refer to this…

We present the results of our analysis of six orbits of HST/STIS time-tagged spectroscopy of the intermediate polar, EX Hydrae. The high time and wavelength resolution of the HST/STIS spectra provided an excellent opportunity to study the…

We construct a new set of self-consistent analytical disk models by taking into account both viscous and radiative sources of thermal energy. We analyze the non-isothermal structure of the disk across the mid-plane for optically thick…

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…

Outbursts due to dramatic increases in the mass accretion rate are the most extreme type of variability in young stellar objects. We searched for outbursts among 319 protostars in the Orion molecular clouds by comparing 3.6, 4.5, and 24…

We analyze Spitzer IRS spectra of 110 B-, A-, F-, and G-type stars with optically thin infrared excess in the Scorpius-Centaurus (ScoCen) OB association. The age of these stars ranges from 11-17 Myr. We fit the infrared excesses observed in…

Using a microlensing analysis of 11-years of OGLE V-band photometry of the four image gravitational lens Q2237+0305, we measure the inclination i of the accretion disk to be cos i > 0.66 at 68% confidence. Very edge on (cos i < 0.39)…

We present 4.5, 8, and 16um photometry from the Spitzer Space Telescope for 204 stars in the Upper Scorpius OB Association. The data are used to investigate the frequency and properties of circumstellar disks around stars with masses…

We report observations of a possible young transiting planet orbiting a previously known weak-lined T-Tauri star in the 7-10 Myr old Orion-OB1a/25-Ori region. The candidate was found as part of the Palomar Transient Factory (PTF) Orion…