GAS in Protoplanetary Systems (GASPS) I. First results

Abstract

Context - Circumstellar discs are ubiquitous around young stars, but rapidly\ndissipate their gas and dust on timescales of a few Myr. The Herschel space\nobservatory allows for the study of the warm disc atmosphere, using\nfar-infrared spectroscopy to measure gas content and excitation conditions, and\nfar-IR photometry to constrain the dust distribution. Aims - We aim to detect\nand characterize the gas content of circumstellar discs in four targets as part\nof the Herschel science demonstration phase. Methods - We carried out sensitive\nmedium resolution spectroscopy and high sensitivity photometry at lambda\n~60-190 micron using the Photodetector Array Camera and Spectrometer instrument\non the Herschel space observatory. Results - We detect [OI] 63 micron emission\nfrom the young stars HD 169142, TW Hydrae, and RECX 15, but not HD 181327. No\nother lines, including [CII] 158 and [OI] 145, are significantly detected. All\nfour stars are detected in photometry at 70 and 160 micron. Extensive models\nare presented in associated papers.\n