Related papers: The Thermal Structure of the Circumstellar Disk Su…
Star formation depends on the available gaseous "fuel" as well as galactic environment, with higher specific star formation rates where gas is predominantly molecular and where stellar (and dark matter) densities are higher. The partition…
We explore the thermal state of the neutron star in the Cassiopeia A supernova remnant using the recent result of Ho & Heinke (Nature, 462, 71 (2009)) that the thermal radiation of this star is well-described by a carbon atmosphere model…
Circumplanetary disks regulate the late accretion to the giant planet and serve as the birthplace for satellites. Understanding their characteristics via simulations also helps to prepare for their observations. Here we study disks around…
This paper introduces a new disk code, called ProDiMo, to calculate the thermo-chemical structure of protoplanetary disks and to interpret gas emission lines from UV to sub-mm. We combine frequency-dependent 2D dust continuum radiative…
Temperature is a crucial parameter in circumstellar disk evolution and planet formation, because it governs the resistance of the gas to gravitational instability and sets the chemical composition of the planet-forming material. We set out…
The disk atmosphere is one of the fundamental elements of theoretical models of a protoplanetary disk. However, the direct observation of the warm gas (>> 100 K) at large radius of a disk (>> 10 AU) is challenging, because the line emission…
A study on the photosphere and disc of the Be star $\beta$ Psc is presented. We recover almost 40 years of high-resolution spectroscopic observations and additional data gathered from the BeSS database. We evaluate the photospheric…
Using high-resolution, three-dimensional hydrodynamical simulations, we investigate the structure of the interstellar medium in the central hundred pc region in galaxies, taking into account self-gravity of the gas, radiative cooling from…
We study dynamics of circumstellar discs, with a focus on the $\beta$ Lyrae A binary system. This system with ongoing mass transfer has been extensively observed, using photometry, spectroscopy and interferometry. All these observations…
The cooling rate of young neutron stars gives direct insight into their internal makeup. Although the temperatures of several young neutron stars have been measured, until now a young neutron star has never been observed to decrease in…
Structure and spectral energy distributions (SEDs) of externally irradiated circumstellar disks are often computed on the basis of the two-temperature model of Chiang & Goldreich. We refine these calculations by using a more realistic…
AB Aur is a Herbig Ae star that hosts a prototypical transition disk. The disk shows a plethora of features connected with planet formation mechanisms. Understanding the physical and chemical characteristics of these features is crucial to…
Aims: We explore the long-term evolution of young protoplanetary disks with different approaches to computing the thermal structure determined by various cooling and heating processes in the disk and its surroundings. Methods: Numerical…
The chemical composition of gas and ice in disks around young stars set the bulk composition of planets. In contrast to protoplanetary disks (Class II), young disks that are still embedded in their natal envelope (Class 0 and I) are…
We present a numerical model describing a circularly symmetric gaseous disk around the Be star chi Ophiuchi. The model is constrained by long-baseline interferometric observations that are sensitive to the H-alpha Balmer line emission from…
Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar disk that is responsible for the observed infrared (IR) excess and emission lines. The influence of binarity on these phenomena remains controversial. We…
The formation of circumplanetary disks is central to our understanding of giant planet formation, influencing their growth rate during the post-runaway phase and observability while embedded in protoplanetary disks. We use 3D global…
gamma Cas has long been famous for its unique hard X-ray characteristics. We report herein on a 53 ks Chandra HETGS observation of this target. An inspection of our spectrum shows that it is quite atypical for a massive star, with…
We present a series of 2-d ($r,\phi$) hydrodynamic simulations of marginally self gravitating disks around protostars using an SPH code. We implement simple dynamical heating and we cool each location as a black body, using a photosphere…
Medium and high resolution spectroscopy of U Equulei from 1 to 4 microns during 1997-2003 has revealed information about its unusual circumstellar envelope, observed previously at optical and radio wavelengths. Strong absorption bands of…