Book contents
- Frontmatter
- Contents
- Preface
- Conference Photograph
- Conference Participants
- Part one Stellar Evolution and Wind Theory
- Part two Wolf-Rayet Ring Nebulae
- Part three Supernovae
- Part four Asymptotic Giant Branch stars
- Mass loss from late type stars
- Kinematics and structure of circumstellar envelopes
- Circumstellar shells of Long–Period Variables
- Observation of circumstellar shells with the IRAM telescopes
- Part five Planetary Nebulae
- Part six Novae and Symbiotic Stars
- Poster Papers
- Author Index
- Object Index
Observation of circumstellar shells with the IRAM telescopes
from Part four - Asymptotic Giant Branch stars
Published online by Cambridge University Press: 07 September 2010
- Frontmatter
- Contents
- Preface
- Conference Photograph
- Conference Participants
- Part one Stellar Evolution and Wind Theory
- Part two Wolf-Rayet Ring Nebulae
- Part three Supernovae
- Part four Asymptotic Giant Branch stars
- Mass loss from late type stars
- Kinematics and structure of circumstellar envelopes
- Circumstellar shells of Long–Period Variables
- Observation of circumstellar shells with the IRAM telescopes
- Part five Planetary Nebulae
- Part six Novae and Symbiotic Stars
- Poster Papers
- Author Index
- Object Index
Summary
Abstract
Recent observations of circumstellar shells at arc second resolutions (i.e., 100 R•, in the case of IRC+10216) reveal clumpy structures, asymmetries and jets. The most recent maps of such objects, observed with the IRAM Plateau de Bure interferometer and Pico Veleta telescope, are presented.
Introduction
The dusty envelopes of late type stars are fascinating objects on their own; they are also interesting for what they teach us about IS chemistry. From their velocity field and density profile, we can study the mass loss during a crucial phase of stellar evolution: since the gas expands at nearly constant velocity in all, but the innermost envelope, the velocity maps yield a 3-D view of the molecule spatial distribution; the distributions of the different molecular species show how photochemical, molecule-molecule and grainsurface reactions proceed with time in a well behaved environment.
The closest massive envelopes lie a few hundred parsecs away and have small angular sizes. The construction of large millimeter-wave interferometers, in particular the IRAM Plateau de Bure interferometer (Guilloteau et al. 1992), has provided a major breakthrough in their investigation.
Molecular emission in IRC+10216
The most remarkable and probably closest massive envelope surrounds the bright IR object IRC+10216 (CW Leo). Its outer radius, observed in the mm lines of 12CO, the most abundant molecule and the best shielded from photodissociation after H2, is R = 3′ (Guélin & Cernicharo, in preparation).
- Type
- Chapter
- Information
- Circumstellar Media in Late Stages of Stellar Evolution , pp. 266 - 273Publisher: Cambridge University PressPrint publication year: 1994