S stars and s-process in the Gaia era

  title={S stars and s-process in the Gaia era},
  author={S. Shetye and Sophie Van Eck and Alain Jorissen and Hans Van Winckel and Lionel Siess and Stephane Goriely and Ana Escorza and Drisya Karinkuzhi and Bertrand Plez},
  journal={Astronomy \& Astrophysics},
Context. S stars are late-type giants that are transition objects between M-type stars and carbon stars on the asymptotic giant branch (AGB). They are classified into two types: intrinsic or extrinsic, based on the presence or absence of technetium (Tc). The Tc-rich or intrinsic S stars are thermally pulsing (TP-)AGB stars internally producing s-process elements (including Tc) that are brought to their surface via the third dredge-up (TDU). The Tc-poor or extrinsic S stars gained their s… 

Observational evidence of third dredge-up occurrence in S-type stars with initial masses around 1 M⊙

Context. S stars are late-type giants with spectra showing characteristic molecular bands of ZrO in addition to the TiO bands typical of M stars. Their overabundance pattern shows the signature of

Binary evolution along the red giant branch with BINSTAR: The barium star perspective

Barium (Ba), CH, and extrinsic or Tc-poor S-type stars are evolved low- and intermediate-mass stars that show enhancement of slow-neutron-capture-process elements on their surface, an indication of

A Fresh Look at AGB Stars in Galactic Open Clusters with Gaia: Impact on Stellar Models and the Initial–Final Mass Relation

Benefiting from the Gaia second and early third releases of photometric and astrometric data, we examine the population of asymptotic giant branch (AGB) stars that appear in the fields of

S-type Stars Discovered in Medium-resolution Spectra of LAMOST DR9

In this paper, we report on 606 S-type stars identified from Data Release 9 of the LAMOST medium-resolution spectroscopic (MRS) survey; 539 of them are reported for the first time. The discovery of

Discovery of technetium- and niobium-rich S stars: The case for bitrinsic stars

Context. S stars are late-type giants with overabundances of s-process elements. They come in two flavors depending on the presence or lack of presence of technetium (Tc), an element without stable

Barium and related stars, and their white-dwarf companions

Barium (Ba) dwarfs and CH subgiants are the less evolved analogues of Ba and CH giants. They are F- to G-type main-sequence stars polluted with heavy elements by their binary companions when the

The Gaia-ESO Survey: detection and characterisation of single-line spectroscopic binaries

Context. Multiple stellar systems play a fundamental role in the formation and evolution of stellar populations in galaxies. Recent and ongoing large ground-based multi-object spectroscopic surveys

Low-mass low-metallicity AGB stars as an efficient i-process site explaining CEMP-rs stars

Context. Among carbon-enhanced metal-poor (CEMP) stars, some are found to be enriched in slow-neutron capture (s-process) elements (and are then tagged CEMP-s), some have overabundances in

Weighing stars from birth to death: mass determination methods across the HRD

The mass of a star is the most fundamental parameter for its structure, evolution, and final fate. It is particularly important for any kind of stellar archaeology and characterization of exoplanets.

Carbon and Oxygen Isotopic Ratios. II. Semiregular Variable M Giants

Carbon and oxygen isotopic ratios are reported for a sample of 51 SRb- and Lb-type variable asymptotic giant branch stars. Vibration-rotation first- and second-overtone CO lines in 1.5–2.5 μm spectra



S Stars without Technetium: The Binary Star Connection

An exploratory survey of non-Mira MS and S star radial velocities and the He I 10830 A triplet are used to test the assertion that S stars without Tc are spectroscopic binaries, probably with

The s process: Nuclear physics, stellar models, and observations

Nucleosynthesis in the $s$ process takes place in the He-burning layers of low-mass asymptotic giant branch (AGB) stars and during the He- and C-burning phases of massive stars. The $s$ process

To Ba or not to Ba: Enrichment in s-process elements in binary systems with WD companions of various masses

Context. The enrichment in s-process elements of barium stars is known to be due to pollution by mass transfer from a companion formerly on the thermally-pulsing asymptotic giant branch (AGB), now a

Heavy-element abundances in seven SC stars and several related stars

We employ spectra of resolution 20–35000 of seven SC stars, four S stars, two Ba stars and two K–M stars to derive abundances of a variety of elements from Sr to Eu relative to iron. Special


Known bright S stars, recognized as such by their enhanced s-process abundances and C/O ratio, are typically members of the asymptotic giant branch (AGB) or the red giant branch. Few modern digital

First stars V - Abundance patterns from C to Zn and supernova yields in the early Galaxy

In the framework of the ESO Large Programme "First Stars", very high-quality spectra of some 70 very metal-poor dwarfs and giants were obtained with the ESO VLT and UVES spectrograph. These stars are

Sensitivity of the s-process nucleosynthesis in AGB stars to the overshoot model

Context. S -process elements are observed at the surface of low- and intermediate-mass stars. These observations can be explained empirically by the so-called partial mixing of protons scenario

Additional late-type stars with technetium

The results of a survey of 279 late-type giants and supergiants for the spectral lines of the radioactive element technetium (Tc I) at 4297, 4262, and 4238 A are presented. The following conclusions


We present new theoretical stellar yields and surface abundances for three grids of metal-rich asymptotic giant branch (AGB) models. Post-processing nucleosynthesis results are presented for stellar

Hertzsprung-Russell diagram and mass distribution of barium stars (Corrigendum)

With the availability of parallaxes provided by the Tycho-Gaia Astrometric Solution, it is possible to construct the Hertzsprung-Russell diagram (HRD) of barium and related stars with unprecedented