Gas and dust in the TW Hydrae Association as seen by the Herschel Space Observatory
P. Riviere-Marichalar, C. Pinte, D. Barrado, W. F. Thi, C. Eiroa, I. Kamp, B. Montesinos, J. Donaldson, J. -C. Augereau, N. Huélamo, A. Roberge, D. Ardila, G. S… 展开作者
P. Riviere-Marichalar, C. Pinte, D. Barrado, W. F. Thi, C. Eiroa, I. Kamp, B. Montesinos, J. Donaldson, J. -C. Augereau, N. Huélamo, A. Roberge, D. Ardila, G. Sandell, J. P. Williams, W. R. F. Dent, F. Menard, J. Lillo-Box, G. Duchêne
Context. Circumstellar discs are the places where planets form, therefore knowledge of their evolution is crucial for our understanding of planet formation. The Herschel Space Observatory is providing valuable data for studying disc systems, thanks to its sensitivity and wavelength coverage. This paper is one of several devoted to analysing and modelling Herschel-PACS observations of various young stellar associations from the GASPS Open Time Key Programme. Aims. The aim of this paper is to elucidate the gas and dust properties of circumstellar discs in the 10 Myr TW Hya Association (TWA) using new far-infrared (IR) imaging and spectroscopy from Herschel-PACS. Methods. We obtained far-IR photometric data at 70, 100, and 160 microns of 14 TWA members; spectroscopic observations centred on the [OI] line at 63.18 microns were also obtained for 9 of the 14. The new photometry for each star was incorporated into its full spectral energy distribution (SED). Results. We detected excess IR emission that is characteristic of circumstellar discs from five TWA members, and computed upper limits for another nine. Two TWA members (TWA 01 and TWA 04B) also show [OI] emission at 63.18 microns. Discs in the TWA association display a variety of properties, with a wide range of dust masses and inner radii, based on modified blackbody modelling. Both transitional and debris discs are found in the sample. Models for sources with a detected IR excess give dust masses in the range from 0.15 Msun to 63 Msun.
The enigmatic nature of the circumstellar envelope and bow shock surrounding Betelgeuse as revealed by Herschel. I. Evidence of clumps, multiple arcs, and a linear bar-like structure
Herschel observations of EXtra-Ordinary Sources: The Terahertz spectrum of Orion KL seen at high spectral resolution
University of Michigan(密歇根大学);California Institute of Technology(加州理工学院);Jet Propulsion Laboratory, Caltech(加州理工学院喷气推进实验室);Observatoire de Paris(巴黎天文台);Université de Toulouse [UPS](图卢兹大学);CNRS/INSU(法国国家科学研究中心)
A set of twenty late-type (K5-M5) stars were observed with the Herschel Space Observatory at 100 and 160 microns with the goal of searching for far-infrared excesses indicative of the presence of circumstellar disks. Out of this sample, four stars (TYC 7443-1102-1, TYC 9340-437-1, GJ 784 and GJ 707) have infrared excesses above their stellar photospheres at either 100 or 160 micron or both. At 100 microns TYC 9340-437-1 is spatially resolved with a shape that suggests it is surrounded by a face-on disk. The 100 micron excess flux associated with GJ 707 is marginal at around 3sigma. The excess …
With the entire Small Magellanic Cloud (SMC) mapped by the Spitzer Space Telescope and Herschel Space Observatory, we were able to search 8-250 micron images in order to identify infrared (IR) emission associated with SMC supernova remnants (SNRs). A valid detection had to correspond with known X-ray, Halpha and radio emission from the SNRs. From the 24 known SNRs, we made 5 positive detections with another 5 possible detections. Two detections are associated with pulsars or pulsar wind nebula, and another three detections are part of the extended nebulous emission from the SNRs. We modelled d…