Orbital properties of binary post-AGB stars

Oomen, Glenn-Michael; Winckel, H. Van; Pols, O. R.; Nelemans, G.; Escorza, A.; Manick, R.; Kamath, D.; Waelkens, Christoffel

doi:10.1051/0004-6361/201833816

Cited by 91 publications

(154 citation statements)

References 102 publications

Supporting

Mentioning

148

Contrasting

Order By: Relevance

“…Since the observed jet velocities are closer to the escape velocity of a main sequence star, we conclude that the companion in this system is most likely a main sequence star. This conclusion is also supported by Oomen et al (2018), who found that based on the initial mass of the companion it is likely a 1M main sequence star.…”

Section: The Best-fitting Jet Modelsupporting

confidence: 60%

A spatio-kinematic model for jets in post-AGB stars,

Bollen

Kamath

Winckel

et al. 2019

A&A

View full text Add to dashboard Cite

Aims. We aim to determine the geometry, density gradient, and velocity structure of jets in post-asymptotic giant branch (post-AGB) binaries. Methods. Our high cadence time series of high-resolution optical spectra of jet-creating post-AGB binary systems provide us with a unique tomography of the jet. We determine the spatio-kinematic structure of the jets based on these data by fitting the synthetic spectral line profiles created by our model to the observed, orbital phase-resolved, Hα-line profiles of these systems. The fitting routine is provided with an initial spectrum and is allowed to test three configurations, derived from three specific jet launching models: a stellar jet launched by the star, an X-wind, and a disk wind configuration. We apply a Markov-chain Monte Carlo routine in order to fit our model to the observations. Our fitting code is tested on the post-AGB binary IRAS19135+3937. Results. We find that a model using the stellar jet configuration gives a marginally better fit to our observations. The jet has a wide half-opening angle of about 76 • and reaches velocities up to 870 km s −1 .Conclusions. Our methodology is successful in determining some parameters for jets in post-AGB binaries. The model for IRAS19135+3937 includes a transparent, low density inner region (for a half-opening angle < 40 • ). The source feeding the accretion disk around the companion is most likely the circumbinary disk. We will apply this jet fitting routine to other jet-creating post-AGB stars in order to provide a more complete description of these objects.

show abstract

Section: The Best-fitting Jet Modelsupporting

confidence: 60%

A spatio-kinematic model for jets in post-AGB stars,

Bollen

Kamath

Winckel

et al. 2019

A&A

View full text Add to dashboard Cite

show abstract

“…Finally, η is the ratio of the specific angular momentum of the disc to that of the binary, while I L is a constant that describes the distribution of angular momentum in the disc (Rafikov 2016a). By taking typical values for a post-AGB binary with L * = 5000 L , a b = 2 AU, and M b = 1.7 M (Oomen et al 2018), and assuming a disc mass of 10 −2 M Kluska et al 2018), we can derive the typical accretion rate onto a post-AGB binary. Here, we take ζ = 0.1, η = 2, α = 0.01, and I L = 1 (see Rafikov 2016b).…”

Section: Accretionmentioning

confidence: 99%

“…Gezer et al 2015). Recent work by Oomen et al (2018) on a sample of post-AGB binaries shows that only post-AGB stars with high temperatures (T eff > 5000 K) in relatively wide orbits (a 1 0.3 AU) are depleted.…”

Section: Introductionmentioning

confidence: 99%

Modelling depletion by re-accretion of gas from a dusty disc in post-AGB stars

Oomen

Winckel

Pols

et al. 2019

A&A

Self Cite

View full text Add to dashboard Cite

Many disc-type post-asymptotic giant branch (post-AGB) stars are chemically peculiar, showing underabundances of refractory elements in their photospheres that correlate with condensation temperature. The aim of this paper is to investigate how accretion from a circumbinary disc can cause this phenomenon of depletion and how this impacts the evolution of post-AGB stars. We used the MESA code to evolve stars in the post-AGB phase, while including accretion of metal-poor gas. We compared the models to a sample of 58 observed disc-type post-AGB stars with chemical abundance data. For each of these stars, we estimated the luminosity and the mass using the Gaia distance. We modelled the accretion rate onto the binary from a viscously evolving disc for a range of initial accretion rates and disc masses. We find that large initial accretion rates ( 3 × 10 −7 M /yr) and large initial disc masses (∼ 10 −2 M ) are needed to reproduce the observed depleted post-AGB stars. Based on these high accretion rates, the evolution timescale of post-AGB stars can be significantly extended by a factor between two and five. We distinguish depletion patterns that are unsaturated (plateau profile) from those that are saturated, and we expect that post-red giant branch (post-RGB) stars are much more likely to show an unsaturated abundance pattern compared to post-AGB stars. Finally, because of the slower evolution of the low-mass post-RGB stars, we find that these systems can become depleted at lower effective temperatures (< 5000 K). We conclude that accretion from a circumbinary disc successfully accounts for the chemical peculiarity of post-AGB stars.

show abstract

“…No systems with periods in the range ∼ 28 − 480 d have been found yet. Oomen et al (2018) published a sample of 33 post-AGB binaries. They have periods similar to the long-period sdB binaries and show other characteristics also seen in the long-period sdB binaries (e.g.…”

Section: Comparison With Related (Eclipsing) Binary Populationsmentioning

confidence: 99%

The EREBOS project: Investigating the effect of substellar and low-mass stellar companions on late stellar evolution

Schaffenroth

Barlow

Geier

et al. 2019

A&A

View full text Add to dashboard Cite

Eclipsing post-common envelope binaries are highly important for resolving the poorly understood, very short-lived common envelope phase of stellar evolution. Most hot subdwarfs (sdO/Bs) are the bare helium-burning cores of red giants which have lost almost all of their hydrogen envelopes. This mass loss is often triggered by common envelope interactions with close stellar or even sub-stellar companions. Cool companions to hot subdwarf stars such as late-type stars and brown dwarfs are detectable from characteristic light curve variations -reflection effects and often eclipses. In the recently published catalog of eclipsing binaries in the Galactic Bulge and in the ATLAS (Asteroid Terrestrial-impact Last Alert System) survey, we discovered 125 new eclipsing systems showing a reflection effect by visual inspection of the light curves and using a machine-learning algorithm, in addition to the 36 systems discovered before by the OGLE (Optical Gravitational Lesing Experiment) team. The EREBOS (Eclipsing Reflection Effect Binaries from Optical Surveys) project aims at analyzing all newly discovered eclipsing binaries of the HW Vir type (hot subdwarf + close, cool companion) based on a spectroscopic and photometric follow up to derive the mass distribution of the companions, constrain the fraction of sub-stellar companions and determine the minimum mass needed to strip off the red-giant envelope. To constrain the nature of the primary we derived the absolute magnitude and the reduced proper motion of all our targets with the help of the parallaxes and proper motions measured by the Gaia mission and compared those to the Gaia white dwarf candidate catalogue. For a sub-set of our targets with observed spectra the nature could be derived by measuring the atmospheric parameter of the primary confirming that less than 10% of our systems are not sdO/Bs with cool companions but white dwarfs or central stars of planetary nebula. This large sample of eclipsing hot subdwarfs with cool companions allowed us to derive a significant period distribution for hot subdwarfs with cool companions for the first time showing that the period distribution is much broader than previously thought and ideally suited to find the lowest mass companions to hot subdwarf stars. The comparison with related binary populations shows that the period distribution of HW Vir systems is very similar to WD+dM systems and central stars of planetary nebula with cool companions. In the future several new photometric surveys will be carried out, which will increase the sample of this project even more giving the potential to test many aspects of common envelope theory and binary evolution.

show abstract

Orbital properties of binary post-AGB stars

Cited by 91 publications

References 102 publications

A spatio-kinematic model for jets in post-AGB stars,

A spatio-kinematic model for jets in post-AGB stars,

Modelling depletion by re-accretion of gas from a dusty disc in post-AGB stars

The EREBOS project: Investigating the effect of substellar and low-mass stellar companions on late stellar evolution

Contact Info

Product

Resources

About