Six intermediate-mass stars with far-infrared excess: a search for evolutionary connections

This is the first of a series of papers presenting the THROES (A caTalogue of HeRschel Observations of Evolved Stars) project, intended to provide a comprehensive overview of the spectroscopic results obtained in the far-infrared (55−670 μm) with the Herschel space observatory on low-to-intermediate mass evolved stars in our Galaxy. Here we introduce the catalogue of interactively reprocessed Photoconductor Array Camera and Spectrometer (PACS) spectra covering the 55−200 μm range for 114 stars in this category for which PACS range spectroscopic data is available in the Herschel Science Archive (HSA). Our sample includes objects spanning a range of evolutionary stages, from the asymptotic giant branch to the planetary nebula phase, displaying a wide variety of chemical and physical properties. The THROES/PACS catalogue is accessible via a dedicated web-based interface and includes not only the science-ready Herschel spectroscopic data for each source, but also complementary photometric and spectroscopic data from other infrared observatories, namely IRAS, ISO, or AKARI, at overlapping wavelengths. Our goal is to create a legacy-value Herschel dataset that can be used by the scientific community in the future to deepen our knowledge and understanding of these latest stages of the evolution of low-to-intermediate mass stars.

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Observing the linked depletion of dust and CO gas at 0.1–10 au in disks of intermediate-mass stars

Astronomy and Astrophysics ◽

10.1051/0004-6361/201732034 ◽

2018 ◽

Vol 609 ◽

pp. L2 ◽

Cited By ~ 14

Author(s):

A. Banzatti ◽

A. Garufi ◽

M. Kama ◽

M. Benisty ◽

S. Brittain ◽

...

Keyword(s):

Near Infrared ◽

Intermediate Mass ◽

Gas Emission ◽

Infrared Excess ◽

Intermediate Mass Stars ◽

Refractory Elements ◽

Definition Of ◽

Disk Region ◽

Co Emission ◽

Co Gas

We report on the discovery of correlations between dust and CO gas tracers of the 0.1–10 au region in planet-forming disks around young intermediate-mass stars. The abundance of refractory elements on stellar photospheres decreases as the location of hot CO gas emission recedes to larger disk radii, and as the near-infrared excess emission from hot dust in the inner disk decreases. The linked behavior between these observables demonstrates that the recession of infrared CO emission to larger disk radii traces an inner disk region where dust is being depleted. We also find that Herbig disk cavities have either low (~5–10%) or high (~20–35%) near-infrared excess, a dichotomy that has not been captured by the classic definition of “pre-transitional” disks.

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AGB Winds with Gas-Dust Drift in Stellar Evolution Codes

Universe ◽

10.3390/universe7050113 ◽

2021 ◽

Vol 7 (5) ◽

pp. 113

Author(s):

Lars Mattsson ◽

Christer Sandin

Keyword(s):

Stellar Evolution ◽

Loss Rate ◽

Mass Loss Rate ◽

Carbon Star ◽

Intermediate Mass ◽

Future Directions ◽

Physical Description ◽

Intermediate Mass Stars ◽

Dust Component ◽

Improved Model

A significant fraction of new metals produced in stars enter the interstellar medium in the form of dust grains. Including dust and wind formation in stellar evolution models of late-stage low- and intermediate-mass stars provides a way to quantify their contribution to the cosmic dust component. In doing so, a correct physical description of dust formation is of course required, but also a reliable prescription for the mass-loss rate. Here, we present an improved model of dust-driven winds to be used in stellar evolution codes and insights from recent detailed numerical simulations of carbon-star winds including drift (decoupling of dust and gas). We also discuss future directions for further improvement.

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IPHAS A-type Stars with Mid-IR Excesses in Spitzer Surveys

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310011932 ◽

2009 ◽

Vol 5 (H15) ◽

pp. 815-815

Author(s):

Antonio S. Hales ◽

Michael J. Barlow ◽

Janet E. Drew ◽

Yvonne C. Unruh ◽

Robert Greimel ◽

...

Keyword(s):

Cross Correlation ◽

Main Sequence ◽

Terrestrial Planet ◽

Circumstellar Disks ◽

Main Sequence Stars ◽

Intermediate Mass ◽

Mid Infrared ◽

Isaac Newton ◽

Intermediate Mass Stars ◽

Dust Disks

AbstractThe Isaac Newton Photometric H-Alpha Survey (IPHAS) provides (r′-Hα)-(r′-i′) colors, which can be used to select AV0-5 Main Sequence star candidates (age~20-200 Myr). By combining a sample of 23050 IPHAS-selected A-type stars with 2MASS, GLIMPSE and MIPSGAL photometry we searched for mid-infrared excesses attributable to dusty circumstellar disks. Positional cross-correlation yielded a sample of 2692 A-type stars, of which 0.6% were found to have 8-μm excesses above the expected photospheric values. The low fraction of main sequence stars with mid-IR excesses found in this work indicates that dust disks in the terrestrial planet zone of Main Sequence intermediate mass stars are rare. Dissipation mechanisms such as photo-evaporation, grain growth, collisional grinding or planet formation could possibly explain the depletion of dust detected in the inner regions of these disks.

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An IRTF-iSHELL Survey of 4.52–5.25 μm CO Spectra in Protoplanetary Disks of Intermediate-mass Stars: Preliminary Sample and Analysis

Research Notes of the AAS ◽

10.3847/2515-5172/abf43a ◽

2021 ◽

Vol 5 (4) ◽

pp. 80

Author(s):

Kirsten M. Abernathy ◽

Andrea Banzatti ◽

Stanley Jensen ◽

Sean Brittain ◽

Adwin Boogert ◽

...

Keyword(s):

Protoplanetary Disks ◽

Intermediate Mass ◽

Intermediate Mass Stars

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Sensitivity of the blue loops of intermediate-mass stars to nuclear reactions

10.1063/1.4768514 ◽

2012 ◽

Author(s):

Ghina M. Halabi ◽

Mounib El Eid

Keyword(s):

Nuclear Reactions ◽

Intermediate Mass ◽

Intermediate Mass Stars

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Disks and outflows around intermediate-mass stars and protostars

Astronomy and Astrophysics ◽

10.1051/0004-6361:20000358 ◽

2001 ◽

Vol 366 (3) ◽

pp. 873-890 ◽

Cited By ~ 67

Author(s):

A. Fuente ◽

R. Neri ◽

J. Martın-Pintado ◽

R. Bachiller ◽

A. Rodrıguez-Franco ◽

...

Keyword(s):

Intermediate Mass ◽

Intermediate Mass Stars

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Near–Infrared Imaging of Proto-Planetary Nebulae

Symposium - International Astronomical Union ◽

10.1017/s0074180900171293 ◽

1993 ◽

Vol 155 ◽

pp. 340-340 ◽

Cited By ~ 1

Author(s):

R.E.S. Clegg ◽

N. A. Walton ◽

M.J. Barlow

Keyword(s):

Molecular Hydrogen ◽

Near Infrared ◽

Infrared Imaging ◽

Planetary Nebulae ◽

Agb Stars ◽

Intermediate Mass ◽

Preliminary Results ◽

Near Ir ◽

Intermediate Mass Stars ◽

Hydrogen Lines

It is not really known how low and intermediate mass stars eject mass to form PNs. We present preliminary results from a programme of near–IR imaging, in which we study a sequence of objects, from extreme AGB stars through proto–planetaries to young, compact PNs. We aim to study the sequence of morphologies, to see where the onset of bipolar shaping occurs, and to use the IR molecular hydrogen lines to map neutral regions around ionized nebulae.

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