- ID:
- ivo://CDS.VizieR/J/ApJS/197/2
- Title:
- Transit timing observations from Kepler. I.
- Short Name:
- J/ApJS/197/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The architectures of multiple planet systems can provide valuable constraints on models of planet formation, including orbital migration, and excitation of orbital eccentricities and inclinations. NASA's Kepler mission has identified 1235 transiting planet candidates. The method of transit timing variations (TTVs) has already confirmed seven planets in two planetary systems. We perform a transit timing analysis of the Kepler planet candidates. We find that at least ~11% of planet candidates currently suitable for TTV analysis show evidence suggestive of TTVs, representing at least ~65 TTV candidates. In all cases, the time span of observations must increase for TTVs to provide strong constraints on planet masses and/or orbits, as expected based on N-body integrations of multiple transiting planet candidate systems (assuming circular and coplanar orbits).
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/208/22
- Title:
- Transit timing variation for 12 planetary pairs
- Short Name:
- J/ApJS/208/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extract transit timing variation (TTV) signals for 12 pairs of transiting planet candidates that are near first-order mean motion resonances (MMR), using publicly available Kepler light curves (Q0-Q14). These pairs show significant sinusoidal TTVs with theoretically predicted periods, which demonstrate these planet candidates are orbiting and interacting in the same system. Although individual masses cannot be accurately extracted based only on TTVs because of the well-known degeneracy between mass and eccentricity, TTV phases and amplitudes can still place upper limits on the masses of the candidates, confirming their planetary nature. Furthermore, the mass ratios of these planet pairs can be relatively tightly constrained using these TTVs. The planetary pair in KOI 880 seems to have particularly high mass and density ratios, which might indicate very different internal compositions of these two planets. Some of these newly confirmed planets are also near MMR with other candidates in the system, forming unique resonance chains (e.g., KOI 500).
- ID:
- ivo://CDS.VizieR/J/ApJS/210/25
- Title:
- Transit timing variation for 15 planetary pairs. II.
- Short Name:
- J/ApJS/210/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Following on from Paper I (Cat. J/ApJS/208/22) in this series, I report the confirmation of a further 30 planets in 15 multiple-planet systems via transit timing variations (TTVs), using the publicly available Kepler light curves (Q0-Q16). All 15 pairs are near first-order mean motion resonances, showing sinusoidal TTVs consistent with theoretically predicted periods, which demonstrate they are orbiting and interacting in the same systems. Although individual masses cannot be accurately extracted based only on TTVs (because of the well known degeneracy between mass and eccentricity), the measured TTV phases and amplitudes can still place relatively tight constraints on their mass ratios and upper limits on their masses, which confirm their planetary nature. Some of these systems (KOI-274, KOI-285, KOI-370, and KOI-2672) are relatively bright and thus suitable for further follow-up observations.
- ID:
- ivo://CDS.VizieR/J/AJ/161/202
- Title:
- Transit timing variations of Kepler-90g and h
- Short Name:
- J/AJ/161/202
- Date:
- 10 Dec 2021
- Publisher:
- CDS
- Description:
- Exoplanet transit-timing variations (TTVs) caused by gravitational forces between planets can be used to determine planetary masses and orbital parameters. Most of the observed TTVs are small and sinusoidal in time, leading to degeneracies between the masses and orbital parameters. Here we report a TTV analysis of Kepler-90g and Kepler-90h, which exhibit large TTVs up to 25hr. With optimization, we find a unique solution that allows us to constrain all of the orbital parameters. The best-fit masses for Kepler-90g and 90h are 15.0_-0.8_^+0.9^M{Earth} (Earth mass) and 203_-5_^+5^M_{Earth}, respectively, with Kepler-90g having an unusually low apparent density of 0.15{+/-}0.05g/cm^3^. The uniqueness of orbital parameter solution enables a long-term dynamical integration, which reveals that although their periods are close to 2:3 orbital resonance, they are not locked in resonance, and the configuration is stable over billions of years. The dynamical history of the system suggests that planet interactions are able to raise the eccentricities and break the resonant lock after the initial formation.
- ID:
- ivo://CDS.VizieR/J/AJ/154/5
- Title:
- Transit timing variations of 145 Kepler planets
- Short Name:
- J/AJ/154/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We conduct a uniform analysis of the transit timing variations (TTVs) of 145 planets from 55 Kepler multiplanet systems to infer planet masses and eccentricities. Eighty of these planets do not have previously reported mass and eccentricity measurements. We employ two complementary methods to fit TTVs: Markov chain Monte Carlo simulations based on N-body integration, and an analytic fitting approach. Mass measurements of 49 planets, including 12 without previously reported masses, meet our criterion for classification as robust. Using mass and radius measurements, we infer the masses of planets' gaseous envelopes for both our TTV sample and transiting planets with radial velocity observations. Insight from analytic TTV formulae allows us to partially circumvent degeneracies inherent to inferring eccentricities from TTV observations. We find that planet eccentricities are generally small, typically a few percent, but in many instances are nonzero.
- ID:
- ivo://CDS.VizieR/J/ApJ/893/27
- Title:
- TRENDS high-contrast imaging survey. VIII.
- Short Name:
- J/ApJ/893/27
- Date:
- 19 Jan 2022 00:39:50
- Publisher:
- CDS
- Description:
- The physical properties of faint stellar and substellar objects often rely on indirect, model-dependent estimates. For example, the masses of brown dwarfs are usually inferred using evolutionary models, which are age dependent and have yet to be properly calibrated. With the goal of identifying new benchmark objects to test low-mass stellar and substellar models, we have carried out a comprehensive adaptive optics survey as part of the TaRgetting bENchmark-objects with the Doppler Spectroscopy (TRENDS) high-contrast imaging program. Using legacy radial velocity measurements from the High Resolution Echelle Spectrometer at Keck, we have identified several dozen stars that show long-term Doppler accelerations. We present follow-up high-contrast observations from the campaign and report the discovery of 31 comoving companions, as well as 11 strong candidate companions, to solar-type stars with well-determined parallax and metallicity values. Benchmark objects of this nature lend themselves to orbit determinations, dynamical mass estimates, and independent compositional assessment. This compendium of benchmark objects will serve as a convenient test group to substantiate theoretical evolutionary and atmospheric models near the hydrogen fusing limit.
- ID:
- ivo://CDS.VizieR/J/MNRAS/389/925
- Title:
- Triple and quadruple stars
- Short Name:
- J/MNRAS/389/925
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The statistics of catalogued quadruple stars consisting of two binaries (hierarchy 2+2), is studied in comparison with triple stars, with respective sample sizes of 81 and 725. Seven representative quadruple systems are discussed in greater detail.
- ID:
- ivo://CDS.VizieR/J/AJ/127/2915
- Title:
- Triple systems (cool primary + hot binary)
- Short Name:
- J/AJ/127/2915
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the course of comparing parameters of evolved cool star plus hot main-sequence star binaries with theoretical isochrones, some discrepancies are found between implied stellar masses and the spectroscopic binary mass function or the measured angular separation. These are naturally explained if there is a third star in the system. Multiplicity is also required to explain some comparisons of "cool plus hot binary" IUE and optical spectral energy distribution analysis with measured flux ratios, especially Tycho's two-color photometry of separate components. Out of a sample of 136 cool-plus-hot binary star systems under study, measurements are now indicating several systems considered double (HD 5373, 23089, 26673, 29094, 49126, 71129, 149379, 179002, 187299), and probably a few others (including HD 136415), to have at least three stellar components. Several other cases of suspected triple systems are confirmed. For comparison, there are eight known triples included in the project. In all, about 25% of the systems contain three or more components within a few arcseconds. Estimated separations are provided, which may be of use when not known from interferometry. In general, the triple systems have one post-main-sequence component and two upper main-sequence components, usually revolving around each other. One new triple system, HD 149379, has as its middle component an F giant in the brief first crossing of the Hertzsprung gap.
- ID:
- ivo://CDS.VizieR/J/A+A/356/541
- Title:
- T Tauri stars in the Sco-Cen OB association
- Short Name:
- J/A+A/356/541
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a search for binarity among young stars, performed in the Scorpius-Centaurus OB association on a sample of 118 X-ray selected T Tauri stars. We use speckle interferometry and direct-imaging observations to find companions in the separation range 0.13-6". After corrections to account for confusion with background stars and for the bias induced by the X-ray selection, we find a multiplicity (number of binaries or multiples divided by number of systems) of 32.6+/-6.1)%, and a number of companions per system of (35.2+/-6.3)%. This is higher by a factor of 1.59+/-0.34 compared to main-sequence stars, but slightly lower than in a sample in the Taurus-Auriga star-forming region that was selected and studied similary. In Scorpius-Centaurus, we find fewer binaries with nearly equal brightness than in Taurus-Auriga. There are significant differences between the period distributions in the two subgroups Upper Scorpius A and B: The peak of the distribution of stars in US-A is at about 10^5^ days, while that of stars in US-B is around 10^6.5^ days. We compared our results with the optical multiplicity survey of Brandner et al. (1996A&A...307..121B), whose sample contains 49 stars that were also observed by us, and find no infrared companions. The flux ratio distributions of close and wide binaries in our sample show no significant difference.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/186
- Title:
- TTVs from Kepler. VI. Statistical tests
- Short Name:
- J/ApJ/756/186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze the deviations of transit times from a linear ephemeris for the Kepler Objects of Interest (KOI) through quarter six of science data. We conduct two statistical tests for all KOIs and a related statistical test for all pairs of KOIs in multi-transiting systems. These tests identify several systems which show potentially interesting transit timing variations (TTVs). Strong TTV systems have been valuable for the confirmation of planets and their mass measurements. Many of the systems identified in this study should prove fruitful for detailed TTV studies.
