- 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).
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- 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/A+A/655/A66
- Title:
- Transit Timing Variations bias in transit surveys
- Short Name:
- J/A+A/655/A66
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Transit Timing Variations (TTVs) can provide useful information for systems observed by transit, by putting constraints on the masses and eccentricities of the observed planets, or even constrain the existence of non-transiting companions. However, TTVs can also act as a detection bias that can prevent the detection of small planets in transit surveys, that would otherwise be detected by standard algorithm such as the Boxed Least Square algorithm (BLS) if their orbit was not perturbed. This bias is especially present for surveys with long baseline, such as Kepler, some of the TESS sectors, and the upcoming PLATO mission. Here we introduce a detection method that is robust to large TTVs, and illustrate it by recovering and confirming a pair of resonant super-Earths with 10 hour TTVs around Kepler-1705 (prev. KOI-4772). The method is based on a neural network trained to recover the tracks of low-SNR perturbed planets in river diagrams. We then recover the transit parameters of these candidates by fitting the lightcurve. The individual transit signal-to-noise of Kepler-1705b and c are about three time smaller than all the previously-known planets with TTVs of 3 hours or more, pushing the boundary in the recovering of these small, dynamically active planets. Recovering this type of object is essential to have a complete picture of the observed planetary systems, solving for a bias not often taken into account in statistical studies of exoplanet populations. In addition, TTVs are a means of obtaining mass estimates which can be essential to studying the internal structure of planets discovered by transit surveys. Finally, we show that due to the strong orbital perturbations, it is possible that the spin of the outer resonant planet of Kepler-1705 is trapped in a sub or super-synchronous spin-orbit resonance. This would have important consequences on the climate of the planet since a non-synchronous spin implies that the flux of the star is spread over the whole planetary surface.
- 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/A+A/555/A92
- Title:
- Transit timing variations on Qatar-1
- Short Name:
- J/A+A/555/A92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Variations in the timing of transiting exoplanets provide a powerful tool detecting additional planets in the system. Thus, the aim of this paper is to discuss the plausibility of transit timing variations on the Qatar-1 system by means of primary transit light curves analysis. Furthermore, we provide an interpretation of the timing variation. We observed Qatar-1 between March 2011 and October 2012 using the 1.2m OLT telescope in Germany and the 0.6m PTST telescope in Spain. We present 26 primary transits of the hot Jupiter Qatar-1b. In total, our light curves cover a baseline of 18 months. We also refine the ephemeris of Qatar-1b, which we find to be T0=2456157.42204+/-0.0001BJD_TDB_ and P=1.4200246+/-0.0000007 days, and improve the system orbital parameters.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A100
- Title:
- Transmission spectroscopy of HAT-P-32b
- Short Name:
- J/A+A/590/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained low-resolution, multi-object spectra of the planet host star HAT-P-32 and multiple comparison stars during a transit event of HAT-P-32b. The spectral flux was binned in 62 narrow channels from 3300 to 10000{AA} and used to create differential photometric light curves. These light curves were analysed for a wavelength dependence of the effective planetary radius.
- ID:
- ivo://CDS.VizieR/I/134
- Title:
- Trapezium Multiple Systems
- Short Name:
- I/134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/658/A170
- Title:
- TRAPPIST-1 best-fit parameters
- Short Name:
- J/A+A/658/A170
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We analyze solutions drawn from the recently published posterior distribution of the TRAPPIST-1 system, which consists of seven Earth-size planets appearing to be in a resonant chain around a red dwarf. We show that all the planets are simultaneously in 2-planet and 3-planet resonances, apart from the innermost pair for which the 2-planet resonant angles circulate. By means of a frequency analysis, we highlight that the transit-timing variation (TTV) signals possess a series of common periods varying from days to decades, which are also present in the variations of the dynamical variables of the system. Shorter periods (e.g., the TTVs characteristic timescale of 1.3yr) are associated with 2-planet mean-motion resonances, while longer periods arise from 3-planet resonances. By use of N-body simulations with migration forces, we explore the origin of the resonant chain of TRAPPIST-1 and find that for particular disc conditions, a chain of resonances -- similar to the observed one -- can be formed which accurately reproduces the observed TTVs. Our analysis suggests that while the 4-yr collected data of observations hold key information on the 2-planet resonant dynamics, further monitoring of TRAPPIST-1 will soon provide signatures of three-body resonances, in particular the 3.3 and 5.1yr periodicities expected for the current best-fit solution. Additional observations would help to assess whether the innermost pair of planets is indeed resonant (its proximity to the 8:5 resonance being challenging to explain), and therefore give additional constraints on formation scenarios.
- ID:
- ivo://CDS.VizieR/J/A+A/658/A133
- Title:
- TRAPPIST-1 h NIR spectrum
- Short Name:
- J/A+A/658/A133
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The TRAPPIST-1 planetary system is favorable for transmission spectroscopy and offers the unique opportunity to study rocky-planets with possibly non-primary envelopes. We present here the transmission spectrum of the seventh planet of the TRAPPIST-1 system, TRAPPIST-1 h (R_P_=0.752R_{Earth}_, Teq=173K) using Hubble Space Telescope (HST), Wide Field Camera 3 Grism 141 (WFC3/G141) data. Our purpose is to reduce the HST observations of the seventh planet of TRAPPIST-1 system and by testing simple atmospheric hypothesis put new constraint on the composition and the nature of the planet. First we extracted and corrected the raw data to obtain a transmission spectrum in the Near-IR band (1.1-1.7um). TRAPPIST-1 is a cold M-dwarf and its activity could affect the transmission spectrum. We correct for stellar modulations using three different stellar contamination models, while some fit better the data, they are statistically not significant and the conclusion remains unchanged concerning the presence or not of an atmosphere. Finally, using a Bayesian atmospheric retrieval code we put new constraints on the atmosphere composition of TRAPPIST-1h. According to the retrieval analysis, there is no evidence of molecular absorption in the Near-InfraRed (NIR) spectrum. This suggests the presence of a high cloud deck or a layer of photochemical hazes in a primary atmosphere or a secondary atmosphere dominated by heavy species like nitrogen. This result could even be the consequence of the lack of an atmosphere as the spectrum is better fitted using a flat-line. Variations of transit depth around 1.3um are likely due to remaining scattering noise and results are not improved while changing the spectral resolution. TRAPPIST-1 h has probably lost its atmosphere or possesses a layer of clouds and hazes blocking the NIR signal. We can not distinguish yet between a primary cloudy or a secondary clear envelope using HST/WFC3 data but we can reject, in most cases with more than 3{sigma} confidence, the hypothesis of a clear atmosphere dominated by hydrogen and helium. By testing forced secondary atmospheric scenario, we find that a CO-rich atmosphere (i.e with a volume mixing ratio of 0.2) is one of the best fit to the spectrum with a Bayes Factor of 1.01 corresponding to a 2.1{sigma} detection.
