We produce and analyse eclipse time variation (ETV) curves for some 2600 Kepler binaries. We find good to excellent evidence for a third body in 222 systems via either the light-travel-time (LTTE) or ...dynamical effect delays. Approximately half of these systems have been discussed in previous work, while the rest are newly reported here. Via detailed analysis of the ETV curves using high-level analytic approximations, we are able to extract system masses and information about the three-dimensional characteristics of the triple for 62 systems which exhibit both LTTE and dynamical delays; for the remaining 160 systems, we give improved LTTE solutions. New techniques of pre-processing the flux time series are applied to eliminate false positive triples and to enhance the ETV curves. The set of triples with outer orbital periods shorter than ∼2000 d is now sufficiently numerous for meaningful statistical analysis. We find that (i) there is a peak near i
m ≃ 40° in the distribution of the triple versus inner binary mutual inclination angles that provides strong confirmation of the operation of Kozai–Lidov cycles with tidal friction; (ii) the median eccentricity of the third-body orbits is e
2 = 0.35; (iii) there is a deficit of triple systems with binary periods ≲1 d and outer periods between ∼50 and 200 d which might help guide the refinement of theories of the formation and evolution of close binaries; and (iv) the substantial fraction of Kepler binaries which have third-body companions is consistent with a very large fraction of all binaries being part of triples.
ABSTRACT
In this work we report the discovery and analysis of three new triply eclipsing triple star systems found with the TESS mission during its observations of the northern skies: TICs 193993801, ...388459317, and 52041148. We utilized the TESS precision photometry of the binary eclipses and third-body eclipsing events, ground-based archival and follow-up photometric data, eclipse timing variations, archival spectral energy distributions, as well as theoretical evolution tracks in a joint photodynamical analysis to deduce the system masses and orbital parameters of both the inner and outer orbits. In one case (TIC 193993801) we also obtained radial velocity measurements of all three stars. This enabled us to ‘calibrate’ our analysis approach with and without ‘truth’ (i.e. RV) data. We find that the masses are good to 1–3 per cent accuracy with RV data and 3–10 per cent without the use of RV data. In all three systems we were able to find the outer orbital period before doing any detailed analysis by searching for a longer-term periodicity in the ASAS-SN archival photometry data – just a few thousand ASAS-SN points enabled us to find the outer periods of 49.28 d, 89.86 d, and 177.0 d, respectively. From our full photodynamical analysis we find that all three systems are coplanar to within 1°−3°. The outer eccentricities of the three systems are 0.003, 0.10, and 0.62, respectively (i.e. spanning a factor of 200). The masses of the three stars {Aa, Ab, and B} in the three systems are: {1.31, 1.19, 1.34}, {1.82, 1.73, 2.19}, and {1.62, 1.48, 2.74} M⊙, respectively.
ABSTRACT
In this work, we report the discovery and analysis of six new compact triply eclipsing triple star systems found with the TESS mission: TICs 37743815, 42565581, 54060695, 178010808, ...242132789, and 456194776. All of these exhibit distinct third-body eclipses where the inner eclipsing binary (EB) occults the third (‘tertiary’) star, or vice versa. We utilized the TESS photometry, archival photometric data, and available archival spectral energy distribution curves (SED) to solve for the properties of all three stars, as well as many of the orbital elements. We describe in detail our SED fits, search of the archival data for the outer orbital period, and the final global photodynamical analyses. From these analyses, we find that all six systems are coplanar to within 0°−5°, and are viewed nearly edge on (i.e. within a couple of degrees). The outer orbital periods and eccentricities of the six systems are {Pout (days), e}: {68.7, 0.36}, {123, 0.16}, {60.7, 0.01}, {69.0, 0.29}, {41.5, 0.01}, {93.9, 0.29}, respectively, in the order the sources are listed above. The masses of all 12 EB stars were in the range of 0.7–1.8 M⊙ and were situated near the main sequence. By contrast, the masses and radii of the tertiary stars ranged from 1.5 to 2.3 M⊙ and 2.9 to 12 R⊙, respectively. We use this information to estimate the occurrence rate of compact flat triple systems..
HD 181068 is the brighter of the two known triply eclipsing hierarchical triple stars in the Kepler field. It has been continuously observed for more than 2 yr with the Kepler space telescope. Of the ...nine quarters of the data, three have been obtained in short-cadence mode, that is one point per 58.9 s. Here we analyse this unique data set to determine absolute physical parameters (most importantly the masses and radii) and full orbital configuration using a sophisticated novel approach. We measure eclipse timing variations (ETVs), which are then combined with the single-lined radial velocity measurements to yield masses in a manner equivalent to double-lined spectroscopic binaries. We have also developed a new light-curve synthesis code that is used to model the triple, mutual eclipses and the effects of the changing tidal field on the stellar surface and the relativistic Doppler beaming. By combining the stellar masses from the ETV study with the simultaneous light-curve analysis we determine the absolute radii of the three stars. Our results indicate that the close and the wide subsystems revolve in almost exactly coplanar and prograde orbits. The newly determined parameters draw a consistent picture of the system with such details that have been beyond reach before.
KIC 8560861 (HD 183648) is a marginally eccentric (e = 0.05) eclipsing binary with an orbital period of P
orb = 31.973 d, exhibiting mmag amplitude pulsations on time-scales of a few days. We present ...the results of the complex analysis of high- and medium-resolution spectroscopic data and Kepler Q0 – Q16 long cadence photometry. The iterative combination of spectral disentangling, atmospheric analysis, radial velocity and eclipse timing variation studies, separation of pulsational features of the light curve, and binary light curve analysis led to the accurate determination of the fundamental stellar parameters. We found that the binary is composed of two main-sequence stars with an age of 0.9 ± 0.2 Gyr, having masses, radii and temperatures of M
1 = 1.93 ± 0.12 M⊙, R
1 = 3.30 ± 0.07 R⊙, T
eff1 = 7650 ± 100 K for the primary, and M
2 = 1.06 ± 0.08 M⊙, R
2 = 1.11 ± 0.03 R⊙, T
eff2 = 6450 ± 100 K for the secondary. After substracting the binary model, we found three independent frequencies, two of which are separated by twice the orbital frequency. We also found an enigmatic half orbital period sinusoidal variation that we attribute to an anomalous ellipsoidal effect. Both of these observations indicate that tidal effects are strongly influencing the luminosity variations of HD 183648. The analysis of the eclipse timing variations revealed both a parabolic trend, and apsidal motion with a period of
$P_\mathrm{apse}^\mathrm{obs}=10\,400\pm 3\,000$
y, which is ten times faster than what is theoretically expected. These findings might indicate the presence of a distant, unseen companion.
A study of nine compact triply eclipsing triples Rappaport, S A; Borkovits, T; Gagliano, R ...
Monthly notices of the Royal Astronomical Society,
03/2023, Letnik:
521, Številka:
1
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
In this work, we report the independent discovery and analysis of nine new compact triply eclipsing triple star systems found with the Transiting Exoplanet Survey Satellite (TESS) mission: ...TICs 47151245, 81525800, 99013269, 229785001, 276162169, 280883908, 294803663, 332521671, and 356324779. Each of these nine systems exhibits distinct third-body eclipses where the third (‘tertiary’) star occults the inner eclipsing binary (EB), or vice versa. We utilize a photodynamical analysis of the TESS photometry, archival photometric data, TESS eclipse timing variations of the EBs, available archival spectral energy distribution (SED) curves, and, in some cases, newly acquired radial velocity observations, to solve for the parameters of all three stars, as well as most of the orbital elements. From these analyses we find that the outer orbits of all nine systems are viewed nearly edge on (i.e. within ≲4°), and six of the systems are coplanar to within 5°; the others have mutual inclination angles of 20°, 41°, and possibly 179° (i.e. a retrograde outer orbit). The outer orbital periods range from 47.8 to 604 d, with eccentricities spanning 0.004–0.61. The masses of all 18 EB stars are in the range of 0.9–2.6 M⊙ and are mostly situated near the main sequence. By contrast, the masses and radii of the tertiary stars range from 1.4 to 2.8 M⊙ and 1.5 to 13 R⊙, respectively. We make use of the system parameters from these nine systems, plus those from a comparable number of compact triply eclipsing triples published previously, to gain some statistical insight into their properties.
ABSTRACT
We report the discovery with the Transiting Exoplanet Survey Satellite (TESS) of a third set of eclipses from V994 Herculis (V994 Her, TIC 424508303), previously only known as a doubly ...eclipsing system. The key implication of this discovery and our analyses is that V994 Her is the second fully characterized (2+2) + 2 sextuple system, in which all three binaries eclipse. In this work, we use a combination of ground-based observations and TESS data to analyse the eclipses of binaries A and B in order to update the parameters of the inner quadruple’s orbit (with a derived period of 1062 ± 2 d). The eclipses of binary C that were detected in the TESS data were also found in older ground-based observations, as well as in more recently obtained observations. The eclipse timing variations of all three pairs were studied in order to detect the mutual perturbations of their constituent stars, as well as those of the inner pairs in the (2 + 2) core. At the longest periods they arise from apsidal motion, which may help constraining parameters of the component stars’ internal structure. We also discuss the relative proximity of the periods of binaries A and B to a 3:2 mean motion resonance. This work represents a step forward in the development of techniques to better understand and characterize multiple star systems, especially those with multiple eclipsing components.
We present the dynamic eclipse mapping method designed specifically to reconstruct the surface intensity patterns of non-radial stellar oscillations on components of eclipsing binaries. The method ...needs a geometric model of the binary, accepts the light curve and the detected pulsation frequencies on input, and on output yields estimates of the pulsation patterns, in the form of images, thus allowing a direct identification of the surface mode numbers (ℓ, m). Since it has minimal modelling requirements and can operate on photometric observations in arbitrary wavelength bands, dynamic eclipse mapping is well suited to analyse the wide-band time series collected by space observatories.
We have investigated the performance and the limitations of the method through extensive numerical tests on simulated data, in which almost all photometrically detectable modes with a latitudinal complexity ℓ− |m| ≤ 4 were properly restored. The method is able by its nature to simultaneously reconstruct multimode pulsations from data covering a sufficient number of eclipses as well as pulsations on components with a tilted rotation axis of a known direction. It can also be applied in principle to isolate the contribution of hidden modes from the light curve.
Sensitivity tests show that moderate errors in the geometric parameters and the assumed limb darkening can be partially tolerated by the inversion, in the sense that the lower degree modes are still recoverable. Tidally induced or mutually resonant pulsations, however, are an obstacle that neither the eclipse mapping nor any other inversion technique can ever surpass.
We conclude that, with reasonable assumptions, dynamic eclipse mapping could be a powerful tool for mode identification, especially in moderately close eclipsing binary systems, where the pulsating component is not seriously affected by tidal interactions so that the pulsations are intrinsic to them, and not a consequence of the binarity.
ABSTRACT
We present extensive ultraviolet (UV) and optical photometric and optical spectroscopic follow-up of supernova (SN) 2021gno by the ‘Precision Observations of Infant Supernova Explosions’ ...(POISE) project, starting less than 2 d after the explosion. Given its intermediate luminosity, fast photometric evolution, and quick transition to the nebular phase with spectra dominated by Ca ii lines, SN 2021gno belongs to the small family of Calcium-rich transients. Moreover, it shows double-peaked light curves, a phenomenon shared with only four other Calcium-rich events. The projected distance from the centre of the host galaxy is not as large as other objects in this family. The initial optical light-curve peaks coincide with a very quick decline of the UV flux, indicating a fast initial cooling phase. Through hydrodynamical modelling of the bolometric light curve and line velocity evolution, we found that the observations are compatible with the explosion of a highly stripped massive star with an ejecta mass of $0.8\, M_\odot$ and a 56Ni mass of 0.024 M⊙. The initial cooling phase (first light-curve peak) is explained by the presence of an extended circumstellar material comprising ∼$10^{-2}\, {\rm M}_{\odot }$ with an extension of $1100\, R_{\odot }$. We discuss if hydrogen features are present in both maximum-light and nebular spectra, and their implications in terms of the proposed progenitor scenarios for Calcium-rich transients.
Context. Despite the fact that VW Cephei is one of the most well-studied contact binaries in the literature, there is no fully consistent model available that can explain every observed property of ...this system. Aims. Our aims are to obtain new spectra along with photometric measurements, to analyze what kind of changes may have happened in the system in the past two decades, and to propose new ideas for explaining them. Methods. For the period analysis we determined ten new times of minima from our light curves, and constructed a new O–C diagram of the system. Radial velocities of the components were determined using the cross-correlation technique. The light curves and radial velocities were modeled simultaneously with the PHOEBE code. All observed spectra were compared to synthetic spectra and equivalent widths (EWs) of the Hα line were measured on their differences. Results. We re-determine the physical parameters of the system according to our new light curve and spectral models. We confirm that the primary component is more active than the secondary, and there is a correlation between spottedness and the chromospheric activity. We propose that the flip-flop phenomenon occurring on the primary component could be a possible explanation of the observed nature of the activity. To explain the period variation of VW Cep, we test two previously suggested scenarios: the presence of a fourth body in the system, and the Applegate-mechanism caused by periodic magnetic activity. We conclude that although none of these mechanisms can be ruled out entirely, the available data suggest that mass transfer with a slowly decreasing rate provides the most likely explanation for the period variation of VW Cep.
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