Kepler Object of Interest Network von Essen, C.; Ofir, A.; Dreizler, S. ...
Astronomy and astrophysics (Berlin),
07/2018, Letnik:
615
Journal Article
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During its four years of photometric observations, the
Kepler
space telescope detected thousands of exoplanets and exoplanet candidates. One of
Kepler
’s greatest heritages has been the confirmation ...and characterization of hundreds of multi-planet systems via transit timing variations (TTVs). However, there are many interesting candidate systems displaying TTVs on such long timescales that the existing
Kepler
observations are of insufficient length to confirm and characterize them by means of this technique. To continue with
Kepler
’s unique work, we have organized the “
Kepler
Object of Interest Network” (KOINet), a multi-site network formed of several telescopes located throughout America, Europe, and Asia. The goals of KOINet are to complete the TTV curves of systems where
Kepler
did not cover the interaction timescales well, to dynamically prove that some candidates are true planets (or not), to dynamically measure the masses and bulk densities of some planets, to find evidence for non-transiting planets in some of the systems, to extend
Kepler
’s baseline adding new data with the main purpose of improving current models of TTVs, and to build a platform that can observe almost anywhere on the northern hemisphere, at almost any time. KOINet has been operational since March 2014. Here we show some promising first results obtained from analyzing seven primary transits of KOI-0410.01, KOI-0525.01, KOI-0760.01, and KOI-0902.01, in addition to the
Kepler
data acquired during the first and second observing seasons of KOINet. While carefully choosing the targets we set demanding constraints on timing precision (at least 1 min) and photometric precision (as good as one part per thousand) that were achieved by means of our observing strategies and data analysis techniques. For KOI-0410.01, new transit data revealed a turnover of its TTVs. We carried out an in-depth study of the system, which is identified in the NASA Data Validation Report as a false positive. Among others, we investigated a gravitationally bound hierarchical triple star system and a planet–star system. While the simultaneous transit fitting of ground- andspace-based data allowed for a planet solution, we could not fully reject the three-star scenario. New data, already scheduled in the upcoming 2018 observing season, will set tighter constraints on the nature of the system.
In the context of the Transit Monitoring in the South project, we present nine new transit observations of the exoplanet OGLE-TR-113b observed with the Gemini South, Magellan Baade, Danish-1.54 m and ...Southern Astrophysical Research telescopes. We perform a homogeneous analysis of these new transits together with 10 literature transits to probe into the potential detection of an orbital decay previously reported for this planet. Our new observations extend the transit monitoring baseline for this system by 6 yr, to a total of more than 13 yr. With our timing analysis we obtained a
$\dot{P}=-1.0 \pm 6.0$
ms yr−1, which rejects previous hints of a larger orbital decay for OGLE-TR-113b. With our updated value of
$\dot{P}$
we can discard tidal quality factors of Q
⋆ < 105 for its host star. Additionally, we calculate a 1σ dispersion of the transit timing variations of 42 s over the 13 yr baseline, which discards additional planets in the system more massive than 0.5–3.0 M⊕ in 1:2, 5:3, 2:1 and 3:1 Mean Motion Resonances with OGLE-TR-113b. Finally, with the joint analysis of the 19 light curves we update transit parameters, such as the relative semimajor axis
$a / R_s = 6.44^{+0.04}_{-0.05}$
, the planet-to-star radius ratio
$R_p / R_s =0.14436^{+0.00096}_{-0.00088}$
, and constrains its orbital inclination to
$i =89.27^{+0.51}_{-0.68}$
deg.
We report five new transit epochs of the extrasolar planet OGLE-TR-111b, observed in the v-HIGH and Bessell delta bands with the FORS1 and FORS2 at the ESO Very Large Telescope between 2008 April and ...May. The new transits have been combined with all previously published transit data for this planet to provide a new transit timing variations (TTVs) analysis of its orbit. We find no TTVs with amplitudes larger than 1.5 minutes over a four-year observation time baseline, in agreement with the recent result by Adams et al. Dynamical simulations fully exclude the presence of additional planets in the system with masses greater than 1.,0.4, and 0.5 M {circled plus} at the 3:2, 1:2, and 2:1 resonances, respectively. We also place an upper limit of about 30 M {circled plus} on the mass of potential second planets in the region between the 3:2 and 1:2 mean-motion resonances.
Context. GJ 1214 b is one of the few known transiting super-Earth-sized exoplanets with a measured mass and radius. It orbits an M-dwarf, only 14.55 pc away, making it a favorable candidate for ...follow-up studies. However, the composition of GJ 1214 b’s mysterious atmosphere has yet to be fully unveiled. Aims. Our goal is to distinguish between the various proposed atmospheric models to explain the properties of GJ 1214 b: hydrogen-rich or hydrogen-He mix, or a heavy molecular weight atmosphere with reflecting high clouds, as latest studies have suggested. Methods. Wavelength-dependent planetary radii measurements from the transit depths in the optical/NIR are the best tool to investigate the atmosphere of GJ 1214 b. We present here (i) photometric transit observations with a narrow-band filter centered on 2.14 μm and a broad-band I-Bessel filter centered on 0.8665 μm, and (ii) transmission spectroscopy in the H and K atmospheric windows that cover three transits. The photometric and spectrophotometric time series obtained were analyzed with MCMC simulations to measure the planetary radii as a function of wavelength. We determined radii ratios of 0.1173-0.0024+0.0022 for I-Bessel and 0.11735-0.00076+0.00072 at 2.14 μm. Results. Our measurements indicate a flat transmission spectrum, in agreement with the last atmospheric models that favor featureless spectra with clouds and high molecular weight compositions.
Kepler Object of Interest Network Freudenthal, J.; von Essen, C.; Ofir, A. ...
Astronomy and astrophysics (Berlin),
08/2019, Letnik:
628
Journal Article
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Context. The Kepler Object of Interest Network (KOINet) is a multi-site network of telescopes around the globe organised for follow-up observations of transiting planet candidate Kepler objects of ...interest with large transit timing variations (TTVs). The main goal of KOINet is the completion of their TTV curves as the Kepler telescope stopped observing the original Kepler field in 2013. Aims. We ensure a comprehensive characterisation of the investigated systems by analysing Kepler data combined with new ground-based transit data using a photodynamical model. This method is applied to the Kepler-82 system leading to its first dynamic analysis. Methods. In order to provide a coherent description of all observations simultaneously, we combine the numerical integration of the gravitational dynamics of a system over the time span of observations with a transit light curve model. To explore the model parameter space, this photodynamical model is coupled with a Markov chain Monte Carlo algorithm. Results. The Kepler-82b/c system shows sinusoidal TTVs due to their near 2:1 resonance dynamical interaction. An additional chopping effect in the TTVs of Kepler-82c hints to a further planet near the 3:2 or 3:1 resonance. We photodynamically analysed Kepler long- and short-cadence data and three new transit observations obtained by KOINet between 2014 and 2018. Our result reveals a non-transiting outer planet with a mass of mf = 20.9 ± 1.0 M⊕ near the 3:2 resonance to the outermost known planet, Kepler-82c. Furthermore, we determined the densities of planets b and c to the significantly more precise values ρb = 0.98−0.14+0.10 g cm−3 $\rho_{\textrm{b}}=0.98_{-0.14}^{+0.10}\;\text{g cm}^{-3}$ ρ b = 0.98 −0.14 +0.10 g cm −3 and ρc = 0.494−0.077+0.066 g cm−3 $\rho_{\textrm{c}}=0.494_{-0.077}^{+0.066}\;\text{g cm}^{-3}$ ρ c = 0.494 −0.077 +0.066 g cm −3 .
Context. The launch of the exoplanet space missions obtaining exquisite photometry from space has resulted in the discovery of thousands of planetary systems with very different physical properties ...and architectures. Among them, the exoplanet CoRoT-29b was identified in the light curves the mission obtained in summer 2011, and presented an asymmetric transit light curve, which was tentatively explained via the effects of gravity darkening. Aims. Transits of CoRoT-29b are measured with precision photometry, to characterize the reported asymmetry in their transit shape. Methods. Using the OSIRIS spectrograph at the 10-m GTC telescope, we perform spectro-photometric differential observations, which allow us to both calculate a high-accuracy photometric light curve, and a study of the color-dependence of the transit. Results. After careful data analysis, we find that the previously reported asymmetry is not present in either of two transits, observed in July 2014 and July 2015 with high photometric precisions of 300 ppm over 5 min. Due to the relative faintness of the star, we do not reach the precision necessary to perform transmission spectroscopy of its atmosphere, but we see no signs of color-dependency of the transit depth or duration. Conclusions. We conclude that the previously reported asymmetry may have been a time-dependent phenomenon, which did not occur in more recent epochs. Alternatively, instrumental effects in the discovery data may need to be reconsidered.
Distractibility is the propensity to behaviorally react to irrelevant information. Although children are more distractible the younger they are, the precise contribution of attentional and motor ...components to distractibility and their developmental trajectories have not been characterized yet. We used a new behavioral paradigm to identify the developmental dynamics of components contributing to distractibility in a large cohort of French participants balanced, between age groups, in gender and socioeconomic status (N = 352; age: 6–25). Results reveal that each measure of these components, namely voluntary attention, distraction, impulsivity, and motor control, present a distinct maturational timeline. In young children, increased distractibility is mostly the result of reduced sustained attention capacities and enhanced distraction, whereas in teenagers, it is the result of decreased motor control and increased impulsivity.
Future technological and product developments will be measured by their improved resource and energy efficiency, as well as their competitiveness, while allowing for effective climate and ...environmental protection.
In this study, hybrid metal-plastic composites are developed combining lightweight design with high material stiffness. Therein, modifications of the polymer core with rubber powder are used to increase the damping properties for lower structure borne-sound as well as sustain high stiffness and low weight. For the elastomer filling, different polymer base materials are compared. Assuring a gentle processing of the thermal sensitive powder, an energy-efficient one-step direct manufacturing has been successfully developed.
SURVEY OF THE PAGODA TIMBER ROOF IN DERNEBURG CASTLE Perria, E.; Sieder, M.; Hoyer, S. ...
International archives of the photogrammetry, remote sensing and spatial information sciences.,
05/2017, Letnik:
XLII-5/W1
Journal Article
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The work analyses the historical roof of Derneburg Castle, in the municipality of Holle, Hildesheim’s district, Lower Saxony, Germany. The roof is assembled according to Laves Balken’s system (Laves ...beam’s system), developed by the architect Georg Ludwig Friedrich Laves (1788–1864). The system has the peculiarity to consist of beams that are split along the half of the cross section, and maintained diverged by wooden wedges, distributed along the length of the beam. The system increases the height of the beam, and elevates the bending capacity of it (Weber, 1964). The work has been developed in the frame of an interdisciplinary project in the fields of architecture, engineering and photogrammetry. Main aim of the project is the developing of a structural model to understand the load-carrying capacity of Laves Balken’s system from the laser-scanning model. For this reason, extensive surveys and photo documentation were collected on three areas of the roof construction, characterized by three peculiar usage of Laves Balken’s system. The work presents the survey of the pagoda-roof that covers the tower of the castle, and problems that can be encountered during the survey of very complex timber constructions.
We report 12 new transit observations of the exoplanet WASP-4b from the Transit Monitoring in the South (TraMoS) project. These transits are combined with all previously published transit data for ...this planet to provide an improved radius measurement of R
p = 1.395 ± 0.022R
jup and improved transit ephemerides. In a new homogeneous analysis in search for transit timing variations (TTVs) we find no evidence of those with rms amplitudes larger than 20 s over a 4-yr time span. This lack of TTVs rules out the presence of additional planets in the system with masses larger than about 2.5, 2.0 and 1.0 M⊕ around the 1:2, 5:3 and 2:1 orbital resonances. Our search for the variation of other parameters, such as orbital inclination and transit depth, also yields negative results over the total time span of the transit observations. Finally, we perform a simple study of stellar spots configurations of the system and conclude that the star rotational period is about 34 d.
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