Slowly, slowly in the wind

Saladino, M. I.; Pols, O. R.; Abate, C.

doi:10.1051/0004-6361/201834598

Cited by 43 publications

(27 citation statements)

References 65 publications

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“…Fig. 5 in Saladino et al 2019). Thus, the Doppler shifts in the line emission from this zone will not exclusively exhibit the typical features of a radial wind, but rather a mixed signal that includes signatures associated with rotation.…”

Section: Anatomy Of the Inner Windmentioning

confidence: 95%

“…5.3) in an AGB wind can be rather extreme (e.g. Saladino et al 2019). Therefore, the absence of v = 0 SiO signal between the location of the tentative companion and the most blue-shifted data points is probably indicative of the absence of suitable conditions for the generation of such emission, rather than the absence of matter.…”

Section: Maser Emission and Mass Of Tentative Companionmentioning

confidence: 99%

“…This means that they not only probe the post-interaction gas that is freely flowing outward (such as seen in CO), but also the pre-and peri-interaction gas, that is undergoing strong hydrodynamical perturbations due to the inferred binary interaction. Hydrodynamical models of spiral-inducing AGB binaries that focus on the wind-companion interaction zone (Mastrodemos & Morris 1998;Mohamed & Podsiadlowski 2012;Saladino et al 2019) show that, before transitioning to a radial wind, most stream lines within the orbital radius of the companion are nearly parallel to the orbital displacement vector (see e.g. Fig.…”

Section: Anatomy Of the Inner Windmentioning

confidence: 99%

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ATOMIUM: A high-resolution view on the highly asymmetric wind of the AGB starπ¹Gruis

Homan

Montargès

Pimpanuwat

et al. 2020

A&A

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The nebular circumstellar environments of cool evolved stars are known to harbour a rich morphological complexity of gaseous structures on different length scales. A large part of these density structures are thought to be brought about by the interaction of the stellar wind with a close companion. The S-type asymptotic giant branch (AGB) star π1Gruis, which has a known companion at ∼440 au and is thought to harbour a second, closer-by (< 10 au) companion, was observed with the Atacama Large Millimeter/submillimeter Array as part of the ATOMIUM Large programme. In this work, the brightest CO, SiO, and HCN molecular line transitions are analysed. The continuum map shows two maxima, separated by 0.04″ (6 au). The CO data unambiguously reveal that π1Gru’s circumstellar environment harbours an inclined, radially outflowing, equatorial density enhancement. It contains a spiral structure at an angle of ∼38 ± 3° with the line-of-sight. The HCN emission in the inner wind reveals a clockwise spiral, with a dynamical crossing time of the spiral arms consistent with a companion at a distance of 0.04″ from the AGB star, which is in agreement with the position of the secondary continuum peak. The inner wind dynamics imply a large acceleration region, consistent with a beta-law power of ∼6. The CO emission suggests that the spiral is approximately Archimedean within 5″, beyond which this trend breaks down as the succession of the spiral arms becomes less periodic. The SiO emission at scales smaller than 0.5″ exhibits signatures of gas in rotation, which is found to fit the expected behaviour of gas in the wind-companion interaction zone. An investigation of SiO maser emission reveals what could be a stream of gas accelerating from the surface of the AGB star to the companion. Using these dynamics, we have tentatively derived an upper limit on the companion mass to be ∼1.1 M⊙.

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Section: Anatomy Of the Inner Windmentioning

confidence: 95%

Section: Maser Emission and Mass Of Tentative Companionmentioning

confidence: 99%

Section: Anatomy Of the Inner Windmentioning

confidence: 99%

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ATOMIUM: A high-resolution view on the highly asymmetric wind of the AGB starπ¹Gruis

Homan

Montargès

Pimpanuwat

et al. 2020

A&A

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“…However, the alternative approach based on a synthetic sample of binary systems is not easy to implement, as it would require building not only a family of pre-mass-transfer systems (which is relatively straightforward), but also post-mass-transfer systems (since the GES sample must contain pre-and post-mass-transfer systems altogether), which is currently unrealistic since the evolutionary channels followed by some post-mass-transfer systems like barium stars are not yet fully understood (e.g. Izzard et al 2010;Saladino et al 2019). This is why we resort to the SB9 catalogue for our detection efficiency estimate.…”

Section: Completeness Correctionmentioning

confidence: 99%

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

Merle

Swaelmen

Eck

et al. 2020

A&A

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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 significantly increase the sample of spectroscopic binaries (SBs) allowing analyses of their statistical properties. Aims. We investigate the repeated spectral observations of the Gaia-ESO Survey internal data release 5 (GES iDR5) to identify and characterise SBs with one visible component (SB1s) in fields covering mainly the discs, the bulge, the CoRot fields, and some stellar clusters and associations. Methods. A statistical χ 2 -test is performed on spectra of the iDR5 subsample of approximately 43 500 stars characterised by at least two observations and a signal-to-noise ratio larger than three. In the GES iDR5, most stars have four observations generally split into two epochs. A careful estimation of the radial velocity (RV) uncertainties is performed. Our sample of RV variables is cleaned from contamination by pulsation-and/or convection-induced variables using Gaia DR2 parallaxes and photometry. Monte-Carlo simulations using the SB9 catalogue of spectroscopic orbits allow to estimate our detection efficiency and to correct the SB1 rate to evaluate the GES SB1 binary fraction and its relation to effective temperature and metallicity. Results. We find 641 (resp., 803) FGK SB1 candidates at the 5σ (resp., 3σ) level. The maximum RV differences range from 2.2 km s −1 at the 5σ confidence level (1.6 km s −1 at 3σ) to 133 km s −1 (in both cases). Among them a quarter of the primaries are giant stars and can be located as far as 10 kpc. The orbital-period distribution is estimated from the RV standard-deviation distribution and reveals that the detected SB1s probe binaries with log P[d] 4. We show that SB1s with dwarf primaries tend to have shorter orbital periods than SB1s with giant primaries. This is consistent with binary interactions removing shorter period systems as the primary ascends the red giant branch. For two systems, tentative orbital solutions with periods of 4 and 6 d are provided. After correcting for detection efficiency, selection biases, and the present-day mass function, we estimate the global GES SB1 fraction to be in the range 7-14% with a typical uncertainty of 4%. A small increase of the SB1 frequency is observed from K-towards F-type stars, in agreement with previous studies. The GES SB1 frequency decreases with metallicity at a rate of (−9 ± 3)% dex −1 in the metallicity range −2.7 ≤[Fe/H]≤ +0.6. This anticorrelation is obtained with a confidence level higher than 93% on a homogeneous sample covering spectral types FGK and a large range of metallicities. When the present-day mass function is accounted for, this rate turns to (−4 ± 2)% dex −1 with a confidence level higher than 88%. In addition we provide the variation of the SB1 fraction with metallicity separately for F, G, and K spectral types, as well as for dwarf and giant primaries.

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“…Circumbinary disks and accretion disks (around the secondary) are conspicuously found in numerical simulations of interacting binary systems (e.g. Mastrodemos, & Morris 1998; Liu et al 2017; Chen et al 2017; Saladino et al 2019, and references therein).…”

Section: Discussionmentioning

confidence: 98%

A rotating fast bipolar wind and disk system around the B[e]-type star MWC 922

Contreras

Báez-Rubio

Alcolea

et al. 2019

A&A

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We present interferometric observations with the Atacama Large Millimeter Array (ALMA) of the free-free continuum and recombination line emission at 1 and 3 mm of the "Red Square Nebula" surrounding the B[e]-type star MWC922. The unknown distance to the source is usually taken to be d=1.7-3 kpc. The unprecedented angular resolution (upto∼0.″02) and exquisite sensitivity of these data unveil, for the first time, the structure and kinematics of the emerging, compact ionized region at its center. We imaged the line emission of H30α and H39α, previously detected with single-dish observations, as well as of H51ϵ, H55γ, and H63δ, detected for the first time in this work. The line emission is seen over a full velocity range of ~180 km s−1 arising in a region of diameter <0.″14 (less than a few hundred au) in the maser line H30α, which is the most intense transition reported here. We resolve the spatio-kinematic structure of a nearly edge-on disk rotating around a central mass of ~10 M⊙ (d=1.7 kpc) or ~18 M⊙ (d=3 kpc), assuming Keplerian rotation. Our data also unveil a fast (~100 km s−1) bipolar ejection (a jet?) orthogonal to the disk. In addition, a slow (<15 km s−1) wind may be lifting off the disk. Both, the slow and the fast winds are found to be rotating in a similar manner to the ionized layers of the disk. This represents the first empirical proof of rotation in a bipolar wind expanding at high velocity (~100 km s−1). The launching radius of the fast wind is found to be <30-51 au i.e., smaller than the inner rim of the ionized disk probed by our observations. We believe that the fast wind is actively being launched, probably by a disk-mediated mechanism in a (accretion?) disk around a possible compact companion. We have modelled our observations using the radiative transfer code MORELI. This has enabled us to describe with unparalleled detail the physical conditions and kinematics in the inner layers of MWC 922, which has revealed itself as an ideal laboratory for studying the interplay of disk rotation and jet-launching. Although the nature of MWC 922 remains unclear, we believe it could be a ~15 M⊙ post-main sequence star in a mass-exchanging binary system. If this is the case, a more realistic value of the distance may be d~3 kpc.

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Slowly, slowly in the wind

Cited by 43 publications

References 65 publications

ATOMIUM: A high-resolution view on the highly asymmetric wind of the AGB starπ¹Gruis

ATOMIUM: A high-resolution view on the highly asymmetric wind of the AGB starπ¹Gruis

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

A rotating fast bipolar wind and disk system around the B[e]-type star MWC 922

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Slowly, slowly in the wind

Cited by 43 publications

References 65 publications

ATOMIUM: A high-resolution view on the highly asymmetric wind of the AGB starπ1Gruis

ATOMIUM: A high-resolution view on the highly asymmetric wind of the AGB starπ1Gruis

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

A rotating fast bipolar wind and disk system around the B[e]-type star MWC 922

Contact Info

Product

Resources

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ATOMIUM: A high-resolution view on the highly asymmetric wind of the AGB starπ¹Gruis

ATOMIUM: A high-resolution view on the highly asymmetric wind of the AGB starπ¹Gruis