相关论文: The young low-mass star ISO-Oph-50: Extreme variab…

We analyze ISO archive data of the nearby bright emission-line star 51 Oph, previously classified as a proto-planetary system similar to beta Pic. The infrared spectrum reveals the presence of gas-phase emission bands of hot (approx 850 K)…

FU Orionis objects are a class of young stars with important bursts in luminosity and which show evidence of accretion and ejection activity. It is generally accepted that they are surrounded by a Keplerian circumstellar disk and an…

X-rays from massive stars are ubiquitous yet not clearly understood. In an XMM-Newton observation devoted to observe the first site of star formation in the $\rho$ Ophiuchi dark cloud, we detect smoothly variable X-ray emission from the…

Circumstellar disc evolution is paramount for the understanding of planet formation. The GASPS program aims at determining the circumstellar gas and solid mass around ~250 pre-main-sequence Herbig Ae and TTauri stars. We aim to understand…

We present new results from a significant extension of our previous high angular resolution (0.3" = 40 AU) Submillimeter Array survey of the 880 um continuum emission from dusty circumstellar disks in the ~1 Myr-old Ophiuchus star-forming…

We report on the eclipse mapping analysis of an ensemble of light curves of the dwarf nova V2051 Oph with the aim to study the spatial distribution of its steady-light and flickering sources. The data are combined to derive the orbital…

We systematically investigate the mid-infrared (MIR; $\lambda>3 ~\mu$m) time variability of uniformly selected $\sim800$ massive young stellar objects (MYSOs) from the Red MSX Source (RMS) survey. Out of the 806 sources, we obtain reliable…

Variability is a defining characteristic of young stellar systems, and optical variability has been heavily studied to select and characterize the photospheric properties of young stars. In recent years, multi-epoch observations sampling a…

We conducted an infrared search for faint companions around 351 young stellar objects in the rho Ophiucus molecular cloud and the Serpens molecular cloud. Nine objects in the Spitzer/IRAC archival images were identified as young stellar…

Recent monitoring programs of ultra cool field M and L dwarfs (low mass stars or brown dwarfs) have uncovered low amplitude photometric I-band variations which may be associated with an inhomogeneous distribution of photospheric…

We have obtained low-resolution optical (0.7-0.98 micron) and near-infrared (1.11-1.34 micron and 0.8-2.5 micron) spectra of twelve isolated planetary-mass candidates (J = 18.2-19.9 mag) of the 3-Myr sigma Orionis star cluster with a view…

Images obtained with the Gemini Multi-Object Spectrograph (GMOS) are used to investigate the stellar content and distance of the dwarf irregular galaxy Kar 50. The brightest object is an HII region, and the bright stellar content is…

We present 0.95--2.5 micron moderate (R = 500) resolution spectra of 19 ISOCAM detected sources in the Chamaeleon I dark cloud. Thirteen of these stars are candidate very low mass members of the cloud proposed by Persi et al. (2000 A&A…

Identifying the population of young stellar objects (YSOs) in high extinction regions is a prerequisite for studies of star formation. This task is not trivial, as reddened background objects can be indistinguishable from YSOs in…

We present J-band photometry and low-resolution optical spectroscopy (600-1000 nm) for one of the faintest substellar member candidates in the young sigma Ori cluster, SOri 47 (I=20.53, Bejar et al. 1999). Its very red (I-J)=3.3+/-0.1 color…

We present HST/NICMOS observations with 0.1" (15 AU) resolution of six young stellar objects in the Taurus star-formation region. The targets of our survey are three Class I IRAS sources (IRAS 04016+2610, IRAS 04248+2612, and IRAS…

We present a catalog of 167 newly discovered, irregular variables spanning a $\sim$7 deg${^2}$ area that encompasses the G 305 star-forming complex, one of the most luminous giant H II regions in the Galaxy. We aim to unveil and…

Binary properties are an important diagnostic of the star and brown dwarf formation processes. While wide binaries appear to be rare in the sub-stellar regime, recent observations have revealed Ophiuchus 162225-240515 (2MASS…

Due to the recent dramatic technological advances, infrared interferometry can now be applied to new classes of objects, resulting in exciting new science prospects, for instance, in the area of high-mass star formation. Although…

We present mid-infrared (MIR) observations, made with the TIMMI2 camera on the ESO 3.6 m telescope, toward 14 young massive star-forming regions. All regions were imaged in the N band, and nine in the Q band, with an angular resolution of ~…