Populations of tidal and pulsating variables in eclipsing binaries

TL;DR

The paper addresses how to rapidly characterize a large population of main-sequence eclipsing binaries (EBs) with pulsations by combining Gaia DR3 $T_{ m eff}$ and $L$ with asteroseismic grids and a manual pulsator vetting workflow. It employs conditional normalising flows trained on the M24 asteroseismic grids to infer fundamental and interior parameters ($M$, $M_c$, $R$, $X_{ m c}/X_{ m i}$) for thousands of targets, while analyzing binarity-induced biases and validating against 2MASS $K_s$ magnitudes. The results show that $M$ and $M_c$ scale with $T_{ m eff}$, that $X_{ m c}/X_{ m i}$ has a broad distribution with ZAMS/TAMS pile-ups, and that g-mode and hybrid pulsators tend to occupy short-period, tidally influenced regimes, with only modest evidence that tides drive the observed pulsation distributions. The work provides a foundational, scalable framework for exploiting future large-scale binary surveys and for integrating asteroseismology into population-level analyses, while highlighting limitations related to model grids and binarity corrections.

Abstract

In this work, we seek to characterise a large sample of 14377 main sequence eclipsing binaries in terms of their stellar, asteroseismic, and orbital properties. We conduct manual vetting on a 4000-target subset of our full 14377-target sample to identify targets with pressure or gravity modes. We infer stellar properties including the mass, convective core mass, radius, and central H fraction for the primary using Gaia Data Release 3 effective temperature and luminosity estimates and a grid of asteroseismically calibrated stellar models. We use surface brightness ratio and radius ratio estimates from previous eclipse analysis to study the effect of binarity on our results. Our manual vetting identifies 751 candidate g-mode pulsators, 131 p-mode pulsators, and a further 48 hybrid pulsators. The inferred stellar properties of the hybrid and p-mode pulsators are highly correlated, while the orbital properties of the hybrid pulsators align best with the g-mode pulsators. The g-mode pulsators themselves show a distribution that peaks around the classical g dor instability region but extends continuously towards higher masses, with no detectable divide between the classical g dor and SPB instability regions. There is evidence at the population level for a heightened level of tidal efficiency in stars showing g-mode or hybrid variability. Correcting the primary mass inference for binarity based on eclipse measurements of the surface brightness and radius ratios results in a relatively small shift towards lower masses. This work provides a working initial characterisation of this sample from which more detailed analyses folding in asteroseismic information can be built. It also provides a foundational understanding of the limitations and capabilities of this kind of rapid, scalable analysis that will be highly relevant in planning the exploitation of future large-scale binary surveys.

Figures (19)

• Figure 1: HRD of all systems with Gaia measurements for the effective temperature and luminosity, with adjoining histograms showing the density distributions for luminosity and temperature for each subclass for each panel. The upper left panel also shows solar metallicity ($Z$=0.014) evolutionary tracks from 1.2 to 9 M$_\odot$ from M24 (solid red/yellow) computed using an exponentially-decaying core-boundary mixing prescription ($f_{\rm ov}$ of 0.015), along with full 1.3 M$_\odot$, 5 M$_\odot$, and 9 M$_\odot$ MIST tracks (grey dashed, choi2016). The coloured variation in each of the M24 tracks shows the effect of varying the rotation from 5-55% (red-yellow) of the initial Keplerian critical rotation frequency.
• Figure 2: $\log$ P vs eccentricity for all inspected stars.
• Figure 3: Orbital period (left) and eccentricity (right) versus our tidal morphology parameter (TMP, see equation \ref{['eq:tmp']}). Upper panels show the tidal-variability subclasses, while the bottom panels show the pulsator subclasses introduced in Fig. \ref{['fig:hrdiag']}
• Figure 4: Mass vs temperature. Mass is inferred using M24's $Z$=0.014 stellar grid using Gaia log$(T_{\rm eff})$ and log$(L)$ estimates.
• Figure 5: Distributions for the radius (upper left), core mass (upper right), central H fraction relative to the initial H fraction $X_{\rm c}/X_{\rm i}$ (lower left) and core mass fraction (lower left) plotted against log$(T_{\rm eff})$.