The primordial binary population

Kouwenhoven, M. B. N.; Brown, A. G. A.; Zinnecker, H.; Kaper, L.; Zwart, Simon F. Portegies

doi:10.1051/0004-6361:20048124

Cited by 182 publications

(300 citation statements)

References 57 publications

Supporting

Mentioning

263

Contrasting

Order By: Relevance

“…The distribution function of mass ratios is generally described as a power law ( f (μ) ∝ μ γ ), but the value of γ is still much debated in the literature (Duquennoy & Mayor 1991;Shatsky & Tokovinin 2002;Kouwenhoven et al 2005) and therefore we will take it as a free parameter 1 . Figure 6 shows the evolution with time of the type Ia SN rate for different models and different SFRs, analogously to Fig.…”

Section: Type Ia Sn Ratesmentioning

confidence: 99%

The chemical evolution of galaxies within the IGIMF theory: the [α/Fe] ratios and downsizing

Recchi

Calura²,

Kroupa³

2009

A&A

106

View full text Add to dashboard Cite

Context. The chemical evolution of galaxies is investigated within the framework of the star formation rate (SFR) dependent integrated galactic initial mass function (IGIMF). Aims. We study how the global chemical evolution of a galaxy and in particular how [α/Fe] abundance ratios are affected by the predicted steepening of the IGIMF with decreasing SFR. Methods. We use analytical and semi-analytical calculations to evaluate the mass-weighted and luminosity-weighted [α/Fe] ratios in early-type galaxies of different masses.Results. The models with variable IGIMF produce an [α/Fe] vs. velocity dispersion relation which has the same slope as the observations of massive galaxies, irrespective of the model parameters, provided that the star formation duration inversely correlates with the mass of the galaxy (downsizing). These models also produce steeper [α/Fe] vs. σ relations in low-mass early-type galaxies and this trend is consistent with the observations. Constant IMF models are able to reproduce the [α/Fe] ratios in large elliptical galaxies as well, but they do not predict this change of slope for small galaxies. In order to obtain the best fit between our results and observations, the downsizing effect (i.e. the shorter duration of the star formation in larger galaxies) must be milder than previously thought.

show abstract

Section: Type Ia Sn Ratesmentioning

confidence: 99%

The chemical evolution of galaxies within the IGIMF theory: the [α/Fe] ratios and downsizing

Recchi

Calura²,

Kroupa³

2009

A&A

106

View full text Add to dashboard Cite

show abstract

“…Raghavan et al 2010;Janson et al 2012), but with a strong bias towards equal masses at small binary separations (De Rosa et al 2014). However, Kouwenhoven et al (2005) found that for a sample of young A-stars, the mass ratio is biased towards unequal masses, indicating that accretion at young ages plays an important role in changing the primordial mass ratio into the one observed in older systems. This is supported by simulations that find accretion occurs primarily onto the secondary (e.g.…”

Section: Introductionmentioning

confidence: 97%

Precession and accretion in circumbinary discs: the case of HD 104237

Dunhill

Cuadra

Dougados

2015

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We present the results of smoothed particle hydrodynamics (SPH) simulations of the disc around the young, eccentric stellar binary HD 104237. We find that the binary clears out a large cavity in the disc, driving a significant eccentricity at the cavity edge. This then precesses around the binary at a rate of˙ = 0.48 • T −1 b , which for HD 104237 corresponds to a precession period of 40 years. We find that the accretion pattern into the cavity and onto the binary changes with this precession, resulting in a periodic accretion variability driven purely by the physical parameters of the binary and its orbit. For each star we find that this results in order of magnitude changes in the accretion rate. We also find that the accretion variability allows the primary to accrete gas at a higher rate than the secondary for approximately half of each precession period. Using a large number of 3-body integrations of test particles orbiting different binaries, we find good agreement between the precession rate of a test particle and our SPH disc precession. These rates also agree very well with the precession rates predicted by the analytic theory of Leung & Lee (2013), showing that their prescription can be accurately used to predict long-term accretion variability timescales for eccentric binaries accreting from a disc. We discuss the implications of our result, and suggest that this process provides a viable way of preserving unequal mass ratios in accreting eccentric binaries in both the stellar and supermassive black hole regimes.

show abstract

“…It is widely recognised that the majority of main sequence stars and pre-main sequence stars are in binary systems and that these binaries have various distributions in mass ratio q, binary separation, and binary frequency (Duquennoy & Mayor 1991;Ghez et al 1993;Kouwenhoven et al 2005;Raghavan et al 2010;Kraus et al 2011;De Rosa et al 2014). For main sequence stars, Duquennoy & Mayor (1991) provided statistics of G-dwarf binary systems.…”

Section: Introductionmentioning

confidence: 99%

“…For young stellar objects (YSOs), the number of binaries with intermediate mass YSOs decreases with increasing q (Kouwenhoven et al 2005). In contrast, the number of binaries with low-mass YSOs increases with increasing q (Kraus et al 2011), and have a log-normal separation distribution.…”

Section: Introductionmentioning

confidence: 99%

Evolution of binary seeds in collapsing protostellar gas clouds

Satsuka

Tsuribe

Tanaka

et al. 2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

We perform three dimensional smoothed particle hydrodynamics (SPH) simulations of gas accretion onto the seeds of binary stars to investigate their short-term evolution. Taking into account of dynamically evolving envelope with non-uniform distribution of gas density and angular momentum of accreting flow, our initial condition includes a seed binary and a surrounding gas envelope, modelling the phase of core collapse of gas cloud when the fragmentation has already occurred. We run multiple simulations with different values of initial mass ratio q 0 (the ratio of secondary over primary mass) and gas temperature. For our simulation setup, we find a critical value of q c = 0.25 which distinguishes the later evolution of mass ratio q as a function of time. If q 0 q c , the secondary seed grows faster and q increases monotonically towards unity. If q 0 q c , on the other hand, the primary seed grows faster and q is lower than q 0 at the end of the simulation. Based on our numerical results, we analytically calculate the long-term evolution of the seed binary including the growth of binary by gas accretion. We find that the seed binary with q 0 q c evolves towards an equal-mass binary star, and that with q 0 q c evolves to a binary with an extreme value of q. Binary separation is a monotonically increasing function of time for any q 0 , suggesting that the binary growth by accretion does not lead to the formation of close binaries.

show abstract

The primordial binary population

Cited by 182 publications

References 57 publications

The chemical evolution of galaxies within the IGIMF theory: the [α/Fe] ratios and downsizing

The chemical evolution of galaxies within the IGIMF theory: the [α/Fe] ratios and downsizing

Precession and accretion in circumbinary discs: the case of HD 104237

Evolution of binary seeds in collapsing protostellar gas clouds

Contact Info

Product

Resources

About