Related papers: Observations of YSO Circumstellar Discs
The study of Young Stellar Objects (YSOs) is one of the most exciting topics that can be undertaken by long baseline optical interferometry. The magnitudes of these objects are at the edge of capabilities of current optical interferometers,…
The formation and early evolution of low mass young stellar objects (YSOs) are investigated using three-dimensional non-ideal magneto-hydrodynamics simulations. We investigate the evolution of YSOs up to ~ 10^4 yr after protostar formation,…
Young circumstellar disks that are still embedded in dense molecular envelopes may differ from their older counterparts, but are historically difficult to study because emission from a disk can be confused with envelope or outflow emission.…
The rarity of young massive stars combined with the fact that they are often deeply embedded has limited the understanding of their formation. Ground based mid-infrared (IR) interferometry is one way of securing the spatial resolution…
(abbreviated) We aim to determine the masses of the envelopes, disks, and central stars of young stellar objects (YSOs) in the Class I stage. We observed the embedded Class I objects IRS 63 and Elias 29 in the rho Ophiuchi star-forming…
The rarity and deeply embedded nature of stars with masses larger than 8 solar masses has limited our understanding of their formation. Previous work has shown that complementing spectral energy distributions with interferometric and…
The time-scale over which and the modality by which young stellar objects (YSOs) disperse their circumstellar discs dramatically influences the eventual formation and evolution of planetary systems. By means of extensive radiative transfer…
We are in a golden era observing Young Stellar Objects (YSOs), protoplanetary disks, and substellar objects, crucial for understanding their formation and evolution. This Ph.D. thesis explores two binary systems. Firstly, we study an…
The key question about early protostellar evolution is how matter is accreted from the large-scale molecular cloud, through the circumstellar disk onto the central star. A sample of 20 Class 0 and I protostars has been observed in continuum…
The very inner structure of massive young stellar objects (YSOs) is difficult to trace. With conventional observational methods we identify structures still several hundreds of AU in size. However, the (proto-)stellar growth takes place at…
We review the use of young low mass stars and protostars, or young stellar objects (YSOs), as tracers of star formation. Observations of molecular clouds at visible, infrared, radio and X-ray wavelengths can identify and characterize the…
Understanding the formation mechanisms of protoplanetary disks and multiple systems, and their pristine properties, is a key question for modern astrophysics. The properties of the youngest disks, embedded in rotating infalling protostellar…
Young massive stars influence their surroundings from local to galactic scales, but the observational challenges associated with their distance and embedded nature has, until the recent decade, made high-resolution studies of these objects…
We review recent advances in our understanding of the innermost regions of the circumstellar environment around young stars, made possible by the technique of long baseline interferometry at infrared wavelengths. Near-infrared observations…
The disks that surround young stars are mostly composed of molecular gas, which is harder to detect and interpret than the accompanying dust. Disk mass measurements have therefore relied on large and uncertain extrapolations from the dust…
Young stellar objects (YSOs) may undergo periods of active accretion (outbursts), during which the protostellar accretion rate is temporarily enhanced by a few orders of magnitude. Whether or not these accretion outburst YSOs possess…
We present K-band polarimetric images of several massive young stellar objects at resolutions $\sim$ 0.1-0.5 arcsec. The polarization vectors around these sources are nearly centro-symmetric, indicating they are dominating the illumination…
We report the results of a study of the intermediate and high mass stars in the young, rich star-forming complex IC 1805, based on a combination of optical, near-infrared, and mid-infrared photometry, and classification spectra. These data…
Near-infrared surveys of high-mass star-forming regions start to shed light onto their stellar content. A particular class of objects found in these regions, the so-called massive Young Stellar Objects (YSOs) are surrounded by dense…
Compact radio emission provides a reliable method for the detection of low luminosity young stellar objects (YSOs), and is particularly useful for detecting the earliest stages of protostellar evolution where the source itself may still be…