相关论文: Dust evolution in the circumstellar disc of the un…
HD 50138 is a southern star that presents the B[e] phenomenon, but its evolutionary stage is still not well known. This object presents spectral variability, which can be explained by outbursts or shell phases and spectropolarimetric…
In this paper we present mid-infrared spectra of a comprehensive set of Herbig Ae/Be stars observed with the Spitzer Space Telescope. The signal-to-noise ratio of these spectra is very high, ranging between about a hundred and several…
The recent findings of gas giant planets around young A-type stars suggest that disks surrounding Herbig Ae/Be stars will develop planetary systems. An interesting case is HD142527, for which previous observations revealed a complex…
Aims. We study a sample of eight B[e] stars with uncertain evolutionary status to shed light on the origin of their circumstellar dust. Methods. We performed a diagnostic analysis on the spectral energy distribution beyond infrared…
HD 50138 is a B[e] star surrounded by a large amount of circumstellar gas and dust. Its spectrum shows characteristics which may indicate either a pre- or a post-main-sequence system. Mapping the kinematics of the gas in the inner few au of…
The formation of dust gaps in protoplanetary disks is one of the most important signposts of disk evolution and possibly the formation of planets. We aim to characterize the 'flaring' disk structure around the Herbig Ae/Be stars HD 100453…
We present spectroscopic observations of a large sample of Herbig Ae stars in the 10 micrometer spectral region. We perform compositional fits of the spectra based on properties of homogeneous as well as inhomogeneous spherical particles,…
Crystalline silicates are an important tracer to the dust evolution in protoplanetary disks. In the inner disk, amorphous silicates are annealed by the high temperatures. These crystalline silicates are radially and vertically distributed…
Herbig Ae/Be objects are pre-main sequence stars surrounded by gas- and dust-rich circumstellar discs. These objects are in the throes of star and planet formation, and their characterisation informs us of the processes and outcomes of…
We investigate the nature of the innermost regions of seven circumstellar disks around pre-main-sequence stars. Our object sample contains disks apparently at various stages of their evolution. Both single stars and spatially resolved…
Young stars are formed within dusty discs. The grains in the disc are originally of the same size as interstellar dust. Models predict that these grains will grow in size through coagulation. Observations of the silicate features at micron…
An essential step to understanding protoplanetary evolution is the study of disks that contain gaps or inner holes. The pretransitional disk around the Herbig star HD 169142 exhibits multi-gap disk structure, differentiated gas and dust…
*Context The evolution of young massive protoplanetary disks toward planetary systems is expected to include the formation of gaps and the depletion of dust and gas. *Aims A special group of flaring disks around Herbig Ae/Be stars do not…
Planet formation has been known for many years to be tied to the spatial distribution of gas and dust in disks around young stars. To constrain planet formation models, imaging observations of protoplanetary disks are required. In this…
Forsterite is one of the crystalline dust species that is often observed in protoplanetary disks and solar system comets. Being absent in the interstellar medium, it must be produced during the disk lifetime. It can therefore serve as a…
A new class of pre-main sequence objects has been recently identified as pre-transitional disks. They present near-infrared excess coupled to a flux deficit at about 10 microns and a rising mid-infrared and far-infrared spectrum. These…
We present multi-instrument observations of the disc around the Herbig~Ae star, HD~145718, employing geometric and Monte Carlo radiative transfer models to explore the disc orientation, the vertical and radial extent of the near infrared…
Context. It is now generally accepted that the near-infrared excess of Herbig AeBe stars originates in the dust of a circumstellar disk. Aims. The aims of this article are to infer the radial and vertical structure of these disks at scales…
Inner regions of protoplanetary disks host many complex physical processes such as star-disk interactions, magnetic fields, planet formation, and the migration of new planets. To directly study this region requires milli-arcsecond angular…
We present Spitzer/IRS spectra of 31 TTS and IRAM/1.3mm observations for 34 low- and intermediate-mass stars in the Cep OB2 region. Including our previously published data, we analyze 56 TTS and the 3 intermediate-mass stars with silicate…