Related papers: Probing Disk Accretion in Young Brown Dwarfs
We present photometry at 3-24um for all known members of the Upper Scorpius association (~11 Myr) based on all images of these objects obtained with the Spitzer Space Telescope and the Wide-field Infrared Survey Explorer. We have used these…
We present the results of a survey for stellar and substellar companions to 82 young stars in the nearby OB association Upper Scorpius. This survey used nonredundant aperture-mask interferometry to achieve typical contrast limits of…
Context: A rich population of low-mass brown dwarfs and isolated planetary mass objects has been reported recently in the Upper Scorpius and Ophiuchus star forming complex. Aims: We investigate the membership, nature and properties of 17 of…
Mass accretion rate determinations are fundamental for an understanding of the evolution of pre-main sequence star circumstellar disks. Magnetospheric accretion models are used to derive values of the mass accretion rates in objects of very…
Using the Spitzer Infrared Spectrograph, we have performed mid-infrared spectroscopy on the young binary brown dwarf 2MASS J04414489+2301513 (15 AU) in the Taurus star-forming region. The spectrum exhibits excess continuum emission that…
Age-benchmark brown dwarfs' and planetary-mass objects' spectroscopy is key to characterize substellar evolution. In this paper we present the JHK medium resolution (R~3000) spectra of 25 7-75 M_Jup (spectral types L3.0-M6.0) brown dwarfs…
We have performed a census of disks around brown dwarfs in the Sigma Ori cluster using all available images from IRAC onboard the Spitzer Space Telescope. To search for new low-mass cluster members with disks, we have measured photometry…
We have completed a systematic survey for disks around young brown dwarfs and very low mass stars. By choosing a well-defined sample and by obtaining sensitive thermal IR observations, we can make an unbiased measurement of the disk…
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…
Magnetohydrodynamic (MHD) and photoevaporative winds are thought to play an important role in the evolution and dispersal of planet-forming disks. Here, we analyze high-resolution ($\Delta v \sim$ 7 kms$^{-1}$) optical spectra from a sample…
We present the results of a radial velocity (RV) survey of 14 brown dwarfs (BDs) and very low-mass (VLM) stars in the Upper Scorpius OB association (UScoOB) and 3 BD candidates in the rho Ophiuchi dark cloud core. We obtained…
Context. Although many studies have been performed so far, there are still dozens of low-mass stars and brown dwarfs in the young sigma Orionis open cluster without detailed spectroscopic characterisation. Aims. We look for unknown strong…
Recent observations show a strong correlation between stellar mass and accretion rate in young stellar and sub-stellar objects, with the scaling $\dot{M}_{acc} \propto M_*^2$ holding over more than four orders of magnitude in accretion…
We have completed an optical spectroscopic survey of an unbiased, extinction-limited sample of candidate young stars covering 1.3 square degrees of the Rho Ophiuchi star forming region. While infrared, X-ray, and optical surveys of the…
An investigation of the magnetospheric accretion and outflow signatures in sub-stellar objects is a natural extension of similar studies conducted on classical T Tauri stars (CTTS), and helps understand if brown dwarfs (BDs) follow the same…
Accretion disks around young stars evolve in time with time scales of few million years. We present here a study of the accretion properties of a sample of 35 stars in the ~3 million year old star-forming region sigma Ori. Of these, 31 are…
We present the results of our studies of the aperiodic optical flux variability for SS Cyg, an accreting binary systemwith a white dwarf. The main set of observational data presented here was obtained with the ANDOR/iXon DU-888 photometer…
We have refined the census of stars and brown dwarfs in the Upper Sco association (~10 Myr, ~145 pc) by 1) updating the selection of candidate members from our previous survey to include the high-precision astrometry from the second data…
An observational review is provided of the properties of accretion disks around young stars. It concerns the primordial disks of intermediate- and high-mass young stellar objects in embedded and optically revealed phases. The properties…
We present high resolution optical spectroscopy of three candidate members of the Taurus-Auriga star forming region. Based on the spectral type, the strength, profile and width of the H(alpha) line, the detected lithium at 6708 angstrom,…