Late Stages of Stellar Evolution - Herschel's contributions

Abstract

Cool objects glow in the infrared. The gas and solid-state species that escape the stellar gravitational attraction of evolved late-type stars in the form of a stellar wind are cool, with temperatures typically $\la$1500\,K, and can be ideally studied in the infrared. These stellar winds create huge extended circumstellar envelopes with extents approaching $10^{19}$\,cm. In these envelopes, a complex kinematical, thermodynamical and chemical interplay determines the global and local structural parameters. Unraveling the wind acceleration mechanisms and deriving the complicated structure of the envelopes is important to understand the late stages of evolution of ~97% of stars in galaxies as our own Milky Way. That way, we can also assess the significant chemical enrichment of the interstellar medium by the mass loss of these evolved stars. The Herschel Space Observatory is uniquely placed to study evolved stars thanks to the excellent capabilities of the three infrared and sub-millimeter instruments on board: PACS, SPIRE and HIFI. In this review, I give an overview of a few important results obtained during the first two years of Herschel observations in the field of evolved low and intermediate mass stars, and I will show how the Herschel observations can solve some historical questions on these late stages of stellar evolution, but also add some new ones.

arXiv commentReview for Advances in Space Research

References in corpus (54)

• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• The Herschel-SPIRE instrument and its in-flight performance
• Too little radiation pressure on dust in the winds of oxygen-rich AGB stars
• A far-infrared survey of bow shocks and detached shells around AGB stars and red supergiants
• Crystalline silicate dust around evolved stars II. The crystalline silicate complexes
• A close halo of large transparent grains around extreme red giant stars
• Oxygen Chemistry in the Circumstellar Envelope of the Carbon-Rich Star IRC+10216
• Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles I. Theoretical model -- Mass-loss history unravelled in VY CMa
• Atmospheric dynamics and the mass loss process in red supergiant stars
• MESS (Mass-loss of Evolved StarS), a Herschel Key Program
• Radiative hydrodynamics simulations of red supergiant stars: II. simulations of convection on Betelgeuse match interferometric observations
• The magnetic field of Betelgeuse: a local dynamo from giant convection cells?
• Warm water vapour in the sooty outflow from a luminous carbon star
• Herschel Inventory of The Agents of Galaxy Evolution (HERITAGE): the Large Magellanic Cloud dust
• 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
• Computing the dust distribution in the bowshock of a fast moving, evolved star
• Origin of quasi-periodic shells in dust forming AGB winds
• Photochemistry in the inner layers of clumpy circumstellar envelopes: formation of water in C-rich objects and of C-bearing molecules in O-rich objects
• Herschel/HIFI observations of O-rich AGB stars : molecular inventory
• First Surface-resolved Results with the IOTA Imaging Interferometer: Detection of Asymmetries in AGB stars
• A spectral line survey in the 2 mm and 1.3 mm windows toward the carbon rich envelope of IRC +10216
• Winds of M- and S-type AGB stars: an unorthodox suggestion for the driving mechanism
• 3D Simulations of Betelgeuse's Bow Shock
• Properties of detached shells around carbon stars: Evidence of interacting winds
• The close circumstellar environment of Betelgeuse - II. Diffraction-limited spectro-imaging from 7.76 to 19.50 microns with VLT/VISIR
• Circumstellar molecular composition of the oxygen-rich AGB star IK~Tau: II. In-depth non-LTE chemical abundance analysis
• Water content and wind acceleration in the envelope around the oxygen-rich AGB star IK Tau as seen by Herschel/HIFI
• Solar-Like Cycle in Asymptotic Giant Branch Stars
• Detection of a Far-Infrared Bow-Shock Nebula Around R Hya: the First MIRIAD Results
• The Astrosphere of the Asymptotic Giant Branch Star Irc+10216
• Sub-au imaging of water vapour clouds around four Asymptotic Giant Branch stars
• AKARI/FIS Mapping of the ISM-Wind Bow Shock around Alpha Ori
• Probing the inner wind of AGB stars: Interferometric observations of SiO millimetre line emission from the oxygen-rich stars R Dor and L2 Pup
• The distribution of SiO in the circumstellar envelope around IRC+10216
• Discovery of multiple dust shells beyond 1 arcmin in the circumstellar envelope of IRC+10216 using Herschel/PACS
• The mineral composition and spatial distribution of the dust ejecta of NGC 6302
• HIFI detection of HF in the carbon star envelope IRC +10216
• Water in IRC+10216: a genuine formation process by shock-induced chemistry in the inner wind
• Herschel's view into Mira's head
• The detached dust shells of AQ And, U Ant, and TT Cyg
• The widespread occurence of water vapor in the circumstellar envelopes of carbon-rich AGB stars: first results from a survey with Herschel/HIFI
• On the physical structure of IRC+10216. Ground-based and Herschel observations of CO and CCH
• Herschel PACS and SPIRE imaging of CW Leo
• Silicon in the dust formation zone of IRC +10216 as observed with PACS and SPIRE on board Herschel
• Detection of `parent' molecules from the inner wind of AGB stars as tracers of non-equilibrium chemistry
• The impact of the 18F(a,p)21Ne reaction on asymptotic giant branch nucleosynthesis
• X Her and TX Psc: Two cases of ISM interaction with stellar winds observed by Herschel
• PACS and SPIRE Spectroscopy of the Red Supergiant VY CMa
• Axial Symmetry and Rotation in the SiO Maser Shell of IK Tauri
• H2O vapor excitation in dusty AGB envelopes. A PACS view of OH 127.8+0.0
• Herschel/HIFI observations of IRC+10216: water vapor in the inner envelope of a carbon-rich AGB star
• The composition and nature of the dust shell surrounding the binary AFGL 4106
• Carbon molecules in the inner wind of the oxygen-rich Mira IK Tauri

Cited by in corpus (9)

• Models of the circumstellar medium of evolving, massive runaway stars moving through the Galactic plane
• Review of scientific topics for Millimetron space observatory
• Herschel/PACS observations of the 69 $\mu m$ band of crystalline olivine around evolved stars
• The problematically short superwind of OH/IR stars - Probing the outflow with the 69 μm spectral band of forsterite
• VLBI Astrometry of AGB Variables with VERA -- A Mira Type Variable T Lepus
• Terahertz-visible two-photon rotational spectroscopy of cold OD-
• Constraints on the H2O formation mechanism in the wind of carbon-rich AGB stars
• Model of the vibrationally excited H${}_2$O maser at 658 GHz in circumstellar envelopes around asymptotic giant branch stars
• H2O Maser Emission in Circumstellar Envelopes around AGB Stars: Physical Conditions in Gas-Dust Clouds