As a significant fraction of stars are in multiple systems, binaries play a crucial role in stellar evolution. Among short-period (<1 day) binary characteristics, age remains one of the most difficult to measure. In this paper, we constrain the lifetime of short-period binaries through their kinematics. With the kinematic information from Gaia Data Release 2 and light curves from {\it Wide-field Infrared Survey Explorer} (WISE), we investigate the eclipsing binary fraction as a function of kinematics for a volume-limited main-sequence sample. We find that the eclipsing binary fraction peaks at a tangential velocity of $10^{1.3-1.6}$ km/s, and decreases towards both low and high velocity end. This implies that thick disk and halo stars have eclipsing binary fraction $\gtrsim 10$ times smaller than the thin-disk stars. This is further supported by the dependence of eclipsing binary fraction on the Galactic latitude. Using Galactic models, we show that our results are inconsistent with any known dependence of binary fraction on metallicity. Instead, our best-fit models suggest that the formation of these short-period binaries is delayed by 0.6-3 Gyr, and the disappearing time is less than the age of the thick disk. The delayed formation time of $\gtrsim0.6$ Gyr implies that these short-period main-sequence binaries cannot be formed by pre-main sequence interaction and the Kozai-Lidov mechanism alone, and suggests that magnetic braking plays a key role in their formation. Because the main-sequence lifetime of our sample is longer than 14 Gyr, if the disappearance of short-period binaries in the old population is due to their finite lifetime, our results imply that most ($\gtrsim90$%) short-period binaries in our sample merge during their main-sequence stage.
Using the recent GAIA eDR3 catalogue we construct a sample of solar neighbourhood isolated wide binaries satisfying a series of strict signal-to-noise data cuts, exclusion of random association criteria and detailed colour-magnitude diagram selections, to minimise the presence of any kinematic contaminating effects having been discussed in the literature to date. Our final high-purity sample consists of 423 binary pairs within 130 pc of the sun and in all cases high-quality GAIA single-stellar fits for both components of each binary (final average RUWE values of 0.99), both also restricted to …
The population of Be/X-ray binaries shows strong evidence of bimodality, especially in the spin period of neutron stars. Several physical mechanisms may produce this bimodality. The most favored candidate mechanisms are two distinct supernova channels or different accretion modes of the neutron stars in Be/X-ray binaries. Investigating the kinematics of these systems may provide some additional insight into the physics of this bimodality. If the two Be/X-ray binary subpopulations arise from two distinct supernova types, then the two subpopulations should have different peculiar (systemic) velo…
The spotted detached eclipsing binary (DEB) offers insights into starspots on the binary. Three spotted DEBs, KIC 8097825, KIC 6859813, and KIC 5527172, which were observed by the Kepler photometry and LAMOST spectroscopy, are studied in this work. The physical parameters of binaries are determined by binary modeling. The sizes, lifetimes, and single/double-dip ratio (SDR) of starspots are derived by starspot analysis. KIC 8097825 has large starspots. KIC 6859813 has a spot rotation period shorter than its orbital period but the system should be synchronized inferred from timescale estimation.…
Reaching the boundary between stellar kinematic groups and very wide binaries. II. alpha Lib + KU Lib: a common proper motion system in Castor separated by 1.0 pc
We explore the hypothesis that B type emission-line stars (Be stars) have their origin in mass-transfer binaries by measuring the fraction of runaway Be stars. We assemble the largest-to-date catalogue of 632 Be stars with 6D kinematics, exploiting the precise astrometry of the Tycho-Gaia Astrometric Solution (TGAS) from the first Gaia Data Release. Using binary stellar evolution simulations, we make predictions for the runaway and equatorial rotation velocities of a runaway Be star population. Accounting for observational biases, we calculate that if all classical Be stars originated through …
We present a detailed analysis of the kinematic properties of the multiple populations (MPs) in the low-mass Galactic globular cluster NGC6362 based on a sample of about 500 member stars for which radial velocities (RVs), Fe and Na abundances have been homogeneously derived. At distances from the cluster center larger than about 0.5 $r_h$, we find that first (FG - Na-poor) and second generation (SG - Na-rich) stars show hints of different line-of-sight velocity dispersion profiles, with FG stars being dynamically hotter. This is the first time that differences in the velocity dispersion of MPs…
Reaching the boundary between stellar kinematic groups and very wide binaries. III. Sixteen new stars and eight new wide systems in the beta Pictoris moving group
We investigated almost 500 stars distributed among 193 binary or multiple systems made of late-F, G-, or early-K primaries and late-K or M dwarf companion candidates. For all of them, we compiled or measured coordinates, J-band magnitudes, spectral types, distances, and proper motions.With these data, we established a sample of 192 physically bound systems. In parallel, we carried out observations with HERMES/Mercator and obtained high resolution spectra for the 192 primaries and five secondaries. We used these spectra and the automatic StePar code for deriving precise stellar atmospheric para…
Aims: With the latest Gaia DR3 data, we analyse the widest pairs in the Washington Double Star (WDS) catalogue with angular separations, $ρ$, greater than 1000 arcsec. Methods: We confirmed the pair's membership to stellar systems based on common proper motions, parallaxes, and (when available) radial velocities, together with the locii of the individual components in colour-magnitude diagrams. We also looked for additional closer companions to the ultrawide pairs, either reported by WDS or found by us with a new Gaia astrometric search. In addition, we determined masses for each star (and whi…
The narrow, neutral Fe Kα fluorescence emission line in X-ray binaries (XRBs) is a powerful probe of the geometry, kinematics and Fe abundance of matter around the accretion flow. In a recent study it has been claimed, using $Chandra$ High-Energy Transmission Grating (HETG) spectra for a sample of XRBs, that the circumnuclear material is consistent with a solar-abundance, uniform, spherical distribution. It was also claimed that the Fe Kα line was unresolved in all cases by the HETG. However, these conclusions were based on ad hoc models that did not attempt to relate the global column density…
Precise and Accurate Mass and Radius Measurements of Thirty Galactic Metal-Poor Stars in Detached Eclipsing Binaries
University of California, Berkeley（加州大学伯克利分校）；The Ohio State University（俄亥俄州立大学）；Center for Cosmology and Astroparticle Physics, The Ohio State University（俄亥俄州立大学宇宙学与天体粒子物理中心）；California Institute of Technology（加州理工学院）；Leibniz-Institut for Astrophysics Potsdam (AIP)（波茨坦莱布尼茨天体物理研究所）；Tufts University（塔夫茨大学）
The population of young stars near the Supermassive black hole (SMBH) in the Galactic Center (GC) has presented an unexpected challenge to theories of star formation. Kinematics measurements of these stars have revealed a stellar disk structure (with an apparent 20% disk membership) that has provided important clues to the origin of these mysterious young stars. However many of the apparent disk properties are difficult to explain, including the low disk membership fraction and the high eccentricities, given the youth of this population. Thus far, all efforts to derive the properties of this d…
About a century ago, Jeans (1919) discovered that if binary stars reach a state approximating energy equipartition, for example through many dynamical encounters that exchange energy, their eccentricity distribution can be described by : dN/de = 2e. This is referred to as the thermal eccentricity distribution, and has been widely used for initial conditions in theoretical investigations of binary stars. However, observations suggest that the eccentricity distributions of most observed binaries, and particularly those with masses < 5 Msun, are flatter than thermal and follow more closely to a u…
Hot Jupiters (HJs), gas giant planets orbiting their host stars with periods on the order of days, commonly occur in the Galaxy, including relatively massive ($1.6-2.4$ $M_\odot$, i.e., A-type main sequence stars) and evolved stars. The majority of A-type main sequence stars have stellar binary companions, which can strongly affect the dynamical evolution of planets around either star. In this work, we investigate the effects of gravitational perturbations by a far away stellar companion on the orbital evolution of gas giant planets orbiting A-type stars, the so-called Eccentric Kozai-Lidov (E…
In astrometric binaries, the presence of a dark, unseen star can be inferred from the gravitational pull it induces on its luminous binary companion. While the orbit of such binaries can be characterized with precise astrometric measurements, constraints made from astrometry alone are not enough to measure the component masses. In this work, we determine the precision with which Gaia can astrometrically measure the orbits and -- with additional observations -- the component masses, for luminous stars hosting hidden companions. Using realistic mock Gaia observations, we find that Gaia can preci…
Identifying long-period eclipsing binaries with space-based photometry is still a challenge even in the century of space telescopes due to the relatively short observation sequences and short lifetime of these missions. The Transiting Exoplanet Survey Satellite (TESS) space telescope is an appropriate tool to supplement previous space-based observations. In this paper we report the first results of the eclipse timing variation (ETV) analyses of eclipsing binaries (EBs) measured by CoRoT and TESS space telescopes. Among the 1428 EB candidates we found 4 new potential triple candidates, for whic…
The presence of a dissipative dark matter (DM) sector may allow for the trapping of a significant DM mass inside stars, either during structure formation or by accretion over their lifetime, influencing stellar behavior well into the Main Sequence stage. Motivated by this scenario, we place an upper bound on the fractional DM mass within current-day Main Sequence stars. Using double-lined spectroscopic binaries (SB2 stars), gravitational masses are extracted and contrasted with luminous masses, derived using a modified mass-luminosity relation which accounts for the effect of DM. High-accuracy…
Most stars form in a clustered environment. Both single and binary stars will sometimes encounter planetary systems in such crowded environments. Encounter rates for binaries may be larger than for single stars, even for binary fractions as low as 10-20 per cent. In this work, we investigate scatterings between a Sun-Jupiter pair and both binary and single stars as in young clusters. We first perform a set of simulations of encounters involving wide ranges of binaries and single stars, finding that wider binaries have larger cross sections for the planet's ejection. Secondly, we consider such …
