Related papers: The weather report from IRC+10216: Evolving irregu…

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…

The physical structures of the outer atmospheres of red giants are not known. They are certainly complex and a range of recent observations are showing that we need to embrace to non-classical atmosphere models to interpret these regions.…

Linear carbon chains are common in various types of astronomical molecular sources. Possible formation mechanisms involve both bottom-up and top-down routes. We have carried out a combined observational and modeling study of the formation…

The nearby Mira-like variable L2 Pup is shown to be undergoing an unprecedented dimming episode. The stability of the period rules out intrinsic changes to the star, leaving dust formation along the line of sight as the most likely…

During the past five years, the Spitzer Space Telescope and improved ground-based facilities have enabled a huge increase in the number of circumstellar disks, around young stars of Solar mass or smaller, in which the composition of the…

We analyse the remnants of CK Vul (Nova Vul 1670) using optical imaging and spectroscopy. The imaging, obtained between 1991 and 2010, spans 5.6% of the life-time of the nebula. The flux of the nebula decreased during the last 2 decades.…

Over the last eight years, the Visual and Infrared Mapping Spectrometer (VIMS) aboard the Cassini orbiter has returned hyperspectral images in the 0.35-5.1 micron range of the icy satellites and rings of Saturn. These very different objects…

Exoplanets on eccentric orbits experience an incident stellar flux that can be markedly larger at periastron versus apoastron. This variation in instellation can lead to dramatic changes in atmospheric structure in regions of the atmosphere…

We present ten years of new photometric monitoring of the light variability of five evolved stars with strong mid-infrared emission from surrounding dust. Three are known carbon-rich proto-planetary nebulae (PPNe) with F$-$G spectral types;…

Certain regions of Saturn's rings exhibit periodic opacity variations with characteristic radial wavelengths of up to a few hundred meters that have been attributed to viscous overstabilities. The Visual and Infrared Mapping Spectrometer…

The atmospheric composition and vertical structure of the super-Earth GJ1214b has been a subject of debate since its discovery in 2009. Recent studies have indicated that high-altitude clouds might mask the lower layers. However, some data…

This chapter summarizes our current understanding of the ionosphere of Saturn. We give an overview of Saturn ionospheric science from the Voyager era to the present, with a focus on the wealth of new data and discoveries enabled by Cassini,…

The imaging of disks around young stars presents extreme challenges in high dynamic range, angular resolution, and sensitivity. Recent instrumental advances have met these challenges admirably, leading to a marked increase in imaging…

The advanced stages of several high-mass stars are characterized by episodic mass loss shed during phases of instability. Key for assigning these stars a proper evolutionary state is to assess the composition and geometry of their ejecta…

We have monitored the Seyfert galaxy NGC 3227 with the Rossi X-ray Timing Explorer (RXTE) since January 1999. During late 2000 and early 2001 we observed an unusual hardening of the 2-10 keV X-ray spectrum which lasted several months. The…

Infrared imaging properties of dusty winds around late-type stars are investigated in detail, employing a self-consistent model that couples the equations of motion and radiative transfer. Because of general scaling properties, the angular…

We have observed with the 30-m IRAM telescope, the CSO telescope and the ISOsatellite (Infrared Space Observatory) the rotational lines of CO at millimeter, submillimeter and far infrared wavelengths in the direction of C-rich stellar…

Phosphine (PH3) was tentatively identified a few years ago in the carbon star envelopes IRC+10216 and CRL2688 from observations of an emission line at 266.9 GHz attributable to the J=1-0 rotational transition. We report the detection of the…

Using ISO-ISOPHOT we carried out a survey of almost 150 stars to search for evidence of emission from dust orbiting young main sequence stars, both in clusters and isolated systems. Over half of the detections are new examples of dusty…

Stars form with gaseous and dusty circumstellar envelopes, which rapidly settle into disks that eventually give rise to planetary systems. Understanding the process by which these disks evolve is paramount in developing an accurate theory…