Planets are formed in disks around young stars. With an age of~ 10 Myr, TW Hya is one of
the nearest T Tauri stars that is still surrounded by a relatively massive disk. In addition a
large number of molecules has been found in the TW Hya disk, making TW Hya the perfect
test case in a large survey of disks with Herschel–PACS to directly study their gaseous
component. We aim to constrain the gas and dust mass of the circumstellar disk around TW
Hya. We observed the fine-structure lines of [O i] and [C ii] as part of the open-time large�…

In an effort to simultaneously study the gas and dust components of the disc surrounding the
young Herbig Ae star HD 169142, we present far-IR observations obtained with the PACS
instrument onboard the Herschel Space Observatory. This work is part of the open time key
program GASPS, which is aimed at studying the evolution of protoplanetary discs. To
constrain the gas properties in the outer disc, we observed the star at several key gas-lines,
including [OI] 63.2 and 145.5 μm,[CII] 157.7 μm, CO 72.8 and 90.2 μm, and oH 2 O 78.7 and�…

Context. Circumstellar discs are ubiquitous around young stars, but rapidly dissipate their
gas and dust on timescales of a few Myr. The Herschel Space Observatory allows for the
study of the warm disc atmosphere, using far-infrared spectroscopy to measure gas content
and excitation conditions, and far-IR photometry to constrain the dust distribution. Aims. We
aim to detect and characterize the gas content of circumstellar discs in four targets as part of
the Herschel science demonstration phase. Methods. We carried out sensitive medium�…