ALMA’s Acute View of pPNe: Through the Magnifying Glass... and What We Found There

We present recent Atacama Large Millimeter/submillimeter Array (ALMA)-based studies of circumstellar envelopes (CSEs) around Asymptotic Giant Branch (AGB) stars and pre-Planetary Nebulae (pPNe). In only a few years of operation, ALMA is revolutionising the field of AGB-to-PN research by providing unprecedentedly detailed information on the complex nebular architecture (at large but also on small scales down to a few ∼10 AU from the centre), dynamics and chemistry of the outflows/envelopes of low-to-intermediate mass stars in their late stages of the evolution. Here, we focus on continuum and molecular line mapping studies with high angular resolution and sensitivity of some objects that are key to understanding the complex PN-shaping process. In particular, we offer (i) a brief summary of ALMA observations of rotating disks in post-AGB objects and (ii) report on ALMA observations of OH 231.8+4.2 providing the most detailed and accurate description of the global nebular structure and kinematics of this iconic object to date.

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AGBs, Post-AGBs and the Shaping of Planetary Nebulae

Galaxies ◽

10.3390/galaxies6030099 ◽

2018 ◽

Vol 6 (3) ◽

pp. 99 ◽

Cited By ~ 1

Author(s):

Eric Lagadec

Keyword(s):

Angular Resolution ◽

Hubble Space Telescope ◽

Planetary Nebulae ◽

High Angular Resolution ◽

Agb Stars ◽

Intermediate Mass ◽

Intermediate Mass Stars ◽

Shaping Process ◽

Huge Variety ◽

Isotropic Radiation

During the last decades, observations, mostly with the Hubble Space Telescope, have revealed that round Planetary Nebulae were the exception rather than rule. A huge variety of features are observed, such as jets, discs, tori, showing that the ejection of material is not due to isotropic radiation pressure on a spherical shell and that more physics is involved. This shaping process certainly occur early in the evolution of these low and intermediate mass stars and must leave imprints in the evolutionary stages prior the PN phase. Thanks to news instruments on the most advanced telescopes (e.g., the VLTI, SPHERE/VLT and ALMA), high angular resolution observations are revolutionising our view of the ejection of gas and dust during the AGB and post-AGB phases. In this review I will present the newest results concerning the mass loss from AGB stars, post-AGB stars and related objects.

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Zooming into the complex dusty envelopes of C-rich AGB stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318006300 ◽

2018 ◽

Vol 14 (S343) ◽

pp. 456-457

Author(s):

Foteini Lykou ◽

Josef Hron ◽

Daniela Klotz

Keyword(s):

Temperature Distribution ◽

Near Infrared ◽

Angular Resolution ◽

High Angular Resolution ◽

Dust Formation ◽

Agb Stars ◽

Circumstellar Envelopes ◽

Recent Advances ◽

Multi Wavelength

AbstractRecent advances in high-angular resolution instruments (VLT and VLTI, ALMA) have enabled us to delve deep into the circumstellar envelopes of AGB stars from the optical to the sub-mm wavelengths, thus allowing us to study in detail the gas and dust formation zones (e.g., their geometry, chemistry and kinematics). This work focuses on four (4) C-rich AGB stars observed with a high-angular resolution technique in the near-infrared: a multi-wavelength tomographic study of the dusty layers of the circumstellar envelopes of these C-rich stars, i.e. the variations in the morphology and temperature distribution.

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Evolutionary timescales from the AGB to the CSPNe phase

Proceedings of the International Astronomical Union ◽

10.1017/s1743921318007330 ◽

2018 ◽

Vol 14 (S343) ◽

pp. 36-46

Author(s):

Marcelo M. Miller Bertolami

Keyword(s):

White Dwarf ◽

New Physics ◽

Asymptotic Giant Branch ◽

Agb Stars ◽

Intermediate Mass ◽

Intermediate Mass Stars

AbstractThe transition from the asymptotic giant branch (AGB) to the final white dwarf (WD) stage is arguably the least understood phase in the evolution of single low- and intermediate-mass stars (0.8 ≲ MZAMS/M⊙ ≲ 8…10). Here we briefly review the progress in the last 50 years of the modeling of stars during the post-AGB phase. We show that although the main features, like the extreme mass dependency of post-AGB timescales were already present in the earliest post-AGB models, the quantitative values of the computed post-AGB timescales changed every time new physics was included in the modeling of post-AGB stars and their progenitors. Then we discuss the predictions and uncertainties of the latest available models regarding the evolutionary timescales of post-AGB stars.

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Monash Chemical Yields Project (Monχey) Element production in low- and intermediate-mass stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316004725 ◽

2015 ◽

Vol 11 (A29B) ◽

pp. 164-165

Author(s):

Carolyn Doherty ◽

John Lattanzio ◽

George Angelou ◽

Simon W. Campbell ◽

Ross Church ◽

...

Keyword(s):

Chemical Evolution ◽

Heavy Element ◽

Internal Surface ◽

Asymptotic Giant Branch ◽

Agb Stars ◽

Galactic Chemical Evolution ◽

Intermediate Mass ◽

Mixing Processes ◽

Intermediate Mass Stars ◽

Solar Metallicity

AbstractThe Monχey project will provide a large and homogeneous set of stellar yields for the low- and intermediate- mass stars and has applications particularly to galactic chemical evolution modelling. We describe our detailed grid of stellar evolutionary models and corresponding nucleosynthetic yields for stars of initial mass 0.8 M⊙ up to the limit for core collapse supernova (CC-SN) ≈ 10 M⊙. Our study covers a broad range of metallicities, ranging from the first, primordial stars (Z = 0) to those of super-solar metallicity (Z = 0.04). The models are evolved from the zero-age main-sequence until the end of the asymptotic giant branch (AGB) and the nucleosynthesis calculations include all elements from H to Bi. A major innovation of our work is the first complete grid of heavy element nucleosynthetic predictions for primordial AGB stars as well as the inclusion of extra-mixing processes (in this case thermohaline) during the red giant branch. We provide a broad overview of our results with implications for galactic chemical evolution as well as highlight interesting results such as heavy element production in dredge-out events of super-AGB stars. We briefly introduce our forthcoming web-based database which provides the evolutionary tracks, structural properties, internal/surface nucleosynthetic compositions and stellar yields. Our web interface includes user- driven plotting capabilities with output available in a range of formats. Our nucleosynthetic results will be available for further use in post processing calculations for dust production yields.

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Constraining ν-process production of fluorine through cosmic ray nucleosynthesis

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2893 ◽

2019 ◽

Vol 490 (3) ◽

pp. 4307-4316 ◽

Cited By ~ 4

Author(s):

Keith A Olive ◽

Elisabeth Vangioni

Keyword(s):

Stellar Evolution ◽

Massive Star ◽

Cosmic Ray ◽

Asymptotic Giant Branch ◽

Agb Stars ◽

Intermediate Mass ◽

Intermediate Mass Stars ◽

Star Production ◽

Low Metallicity ◽

Galactic Cosmic Ray

ABSTRACT Fluorine is massive enough that it is not considered to be a light (Z ≤ 5) element, yet compared to its near neighbours, C, N, O, and Ne, it is far underproduced in the course of stellar evolution, making its origin more complex. In fact, the abundance of fluorine is the lowest among all elements between Z = 5 and 21 and is roughly 3–4 orders of magnitude below that of C, N, O, and Ne. There are several plausible sources for F beyond standard stellar evolution. These include the production in the asymptotic giant branch phase (AGB) in intermediate-mass stars, production in Wolf–Rayet stars, and the production through neutrino spallation in supernovae. The latter, known as the ν-process, is an important source for 11B, and may contribute to the abundance of 7Li as well. We combine a simple model of Galactic chemical evolution with a standard Galactic cosmic ray nucleosynthesis model to treat self-consistently the evolution of the Li, Be, and B isotopes. We include massive star production of F, as well as contributions from AGB stars, and the ν-process. Given the uncertainties in neutrino energies in supernovae, we normalize the ν-process using the observed 11B/10B ratio as a constraint. As a consequence, we are able to determine the relative importance of each contribution to the F abundance. We find that although the ν-process dominates at early times (low metallicity), the present-day F abundance is found to originate primarily from AGB stars.

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New models for the evolution of central stars of planetary nebulae: Faster and Brighter

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317001533 ◽

2016 ◽

Vol 12 (S323) ◽

pp. 179-183

Author(s):

Marcelo M. Miller Bertolami

Keyword(s):

Planetary Nebulae ◽

Asymptotic Giant Branch ◽

Agb Stars ◽

Intermediate Mass ◽

Short Article ◽

Intermediate Mass Stars ◽

New Models ◽

Central Stars

AbstractThe post-asymptotic giant branch (AGB) phase is arguably one of the least understood phases of the evolution of low- and intermediate- mass stars. The recent post-AGB evolutionary sequences computed by Miller Bertolami (2016) are at least three to ten times faster than those previously published by Vassiliadis & Wood (1994) and Blöcker (1995) which have been used in a large number of studies. This is true for the whole mass and metallicity range. The new models are also ~0.1–0.3 dex brighter than the previous models with similar remnant masses. In this short article we comment on the main reasons behind these differences, and discuss possible implications for other studies of post-AGB stars or planetary nebulae.

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Stellar yields – theory and observations

Proceedings of the International Astronomical Union ◽

10.1017/s1743921316004713 ◽

2015 ◽

Vol 11 (A29B) ◽

pp. 162-163

Author(s):

Amanda I. Karakas

Keyword(s):

Chemical Evolution ◽

Stellar Evolution ◽

Theoretical Calculations ◽

Theoretical Models ◽

Asymptotic Giant Branch ◽

Agb Stars ◽

Intermediate Mass ◽

Intermediate Mass Stars ◽

Chemically Peculiar ◽

Essential Tool

AbstractStellar yields are an essential tool for studies of chemical evolution. For low and intermediate-mass stars (0.8 up to 8-10M⊙) the richest nucleosynthesis occurs when the stars are on the asymptotic giant branch (AGB) of stellar evolution. We discuss the main nucleosynthesis outcomes, along with the uncertainties that affect the theoretical calculations. The uncertainties in the physics can be improved by comparing theoretical models to observations, including chemically peculiar metal-poor stars, along with AGB stars and their progeny.

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Asymptotic Giant Branch Evolution and the Initial-Final Mass Relation of Single CO White Dwarfs

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312014664 ◽

2011 ◽

Vol 7 (S281) ◽

pp. 36-43

Author(s):

Paola Marigo

Keyword(s):

Mass Loss ◽

White Dwarfs ◽

Asymptotic Giant Branch ◽

Mass Relation ◽

Evolutionary Models ◽

Agb Stars ◽

Intermediate Mass ◽

Intermediate Mass Stars ◽

Final Mass ◽

The Impact

AbstractCombining recent mass determinations of Galactic CO white dwarfs and their progenitors with the latest evolutionary models for Asymptotic Giant Branch (AGB) stars, I review the initial-final mass relation (IFMR) of low- and intermediate-mass stars. In particular, I analyze the impact on the IFMR produced by a few critical processes characterizing the AGB phase, namely: the second and third dredge-up events, hot-bottom burning, and mass loss. Their dependence on metallicity and related theoretical uncertainties are briefly discussed.

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Parameterizing the Third Dredge up in AGB Stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900208140 ◽

2003 ◽

Vol 209 ◽

pp. 82-82 ◽

Cited By ~ 1

Author(s):

A. I. Karakas ◽

J. C. Lattanzio ◽

O. R. Pols

Keyword(s):

Mass Loss ◽

Main Sequence ◽

Asymptotic Giant Branch ◽

Agb Stars ◽

Intermediate Mass ◽

The Third ◽

Intermediate Mass Stars

We present new evolutionary sequences for low and intermediate mass stars (1M⊙ to 6M⊙) for three different metallicities, z = 0.02, 0.008 and 0.004. We evolve the models from the pre-main sequence to the thermally-pulsing asymptotic giant branch (AGB) phase. We have two sequences of models for each mass, one which includes mass-loss and one without mass-loss. For an overview of AGB evolution and nucleosynthesis, see Herwig (2002) and Lattanzio (2002).

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(Sub)stellar companions shape the winds of evolved stars

Science ◽

10.1126/science.abb1229 ◽

2020 ◽

Vol 369 (6510) ◽

pp. 1497-1500 ◽

Cited By ~ 3

Author(s):

L. Decin ◽

M. Montargès ◽

A. M. S. Richards ◽

C. A. Gottlieb ◽

W. Homan ◽

...

Keyword(s):

Planetary Nebula ◽

Loss Rate ◽

Mass Loss Rate ◽

Asymptotic Giant Branch ◽

Binary Interaction ◽

Agb Stars ◽

Intermediate Mass ◽

Evolved Stars ◽

Intermediate Mass Stars ◽

Evolutionary Scenario

Binary interactions dominate the evolution of massive stars, but their role is less clear for low- and intermediate-mass stars. The evolution of a spherical wind from an asymptotic giant branch (AGB) star into a nonspherical planetary nebula (PN) could be due to binary interactions. We observed a sample of AGB stars with the Atacama Large Millimeter/submillimeter Array (ALMA) and found that their winds exhibit distinct nonspherical geometries with morphological similarities to planetary nebulae (PNe). We infer that the same physics shapes both AGB winds and PNe; additionally, the morphology and AGB mass-loss rate are correlated. These characteristics can be explained by binary interaction. We propose an evolutionary scenario for AGB morphologies that is consistent with observed phenomena in AGB stars and PNe.

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