77 research outputs found

    Kepler-16: A Transiting Circumbinary Planet

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    We report the detection of a planet whose orbit surrounds a pair of low-mass stars. Data from the Kepler spacecraft reveal transits of the planet across both stars, in addition to the mutual eclipses of the stars, giving precise constraints on the absolute dimensions of all three bodies. The planet is comparable to Saturn in mass and size, and is on a nearly circular 229-day orbit around its two parent stars. The eclipsing stars are 20% and 69% as massive as the sun, and have an eccentric 41-day orbit. The motions of all three bodies are confined to within 0.5 degree of a single plane, suggesting that the planet formed within a circumbinary disk.Comment: Science, in press; for supplemental material see http://www.sciencemag.org/content/suppl/2011/09/14/333.6049.1602.DC1/1210923.Doyle.SOM.pd

    Two warm, low-density sub-Jovian planets orbiting bright stars in K2 campaigns 13 and 14

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    We report the discovery of two planets transiting the bright stars HD 89345 (EPIC 248777106, V=9.376V=9.376, K=7.721K=7.721) in K2 Campaign 14 and HD 286123 (EPIC 247098361, V=9.822V=9.822, K=8.434K=8.434) in K2 Campaign 13. Both stars are G-type stars, one of which is at or near the end of its main sequence lifetime, and the other that is just over halfway through its main sequence lifetime. HD 89345 hosts a warm sub-Saturn (0.66 RJR_J, 0.11 MJM_J, Teq=1100T_\mathrm{eq}=1100 K) in an 11.81-day orbit. The planet is similar in size to WASP-107b, which falls in the transition region between ice giants and gas giants. HD 286123 hosts a Jupiter-sized, low-mass planet (1.06 RJR_J, 0.39 MJM_J, Teq=1000T_\mathrm{eq}=1000 K) in an 11.17-day, mildly eccentric orbit, with e=0.255±0.035e=0.255\pm0.035. Given that they orbit relatively evolved main-sequence stars and have orbital periods longer than 10 days, these planets are interesting candidates for studies of gas planet evolution, migration, and (potentially) re-inflation. Both planets have spent their entire lifetimes near the proposed stellar irradiation threshold at which giant planets become inflated, and neither shows any sign of radius inflation. They probe the regime where inflation begins to become noticeable and are valuable in constraining planet inflation models. In addition, the brightness of the host stars, combined with large atmospheric scale heights of the planets, makes these two systems favorable targets for transit spectroscopy to study their atmospheres and perhaps provide insight into the physical mechanisms that lead to inflated hot Jupiters.Comment: 16 pages, 12 figures; accepted for publication in A

    Estudio de casos: tensiones y desafíos en la elaboración de la normativa escolar en Chile

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    Resumen La convivencia escolar es un escenario que ha estado en la reflexión y ha sido transversal en las distintas esferas educativas en los últimos años. De hecho, en el año 2011, el Ministerio de Educación estableció la Ley de Violencia Escolar como una forma de diseñar e implementar líneas de acción que propendan a fortalecer la relación entre los miembros de la comunidad educativa contribuyendo con ello a propiciar un ambiente que permita el desarrollo armónico de todos los actores educativos que forman parte del centro escolar. Con referencia a lo anterior, se realizó un estudio de casos de carácter interpretativo el cual consideró una intervención socioeducativa en un centro escolar público con la finalidad de implementar de manera representativa un marco normativo para la convivencia escolar armónica con la participación de todos los agentes educativos, considerando para ello los diversos significados y comportamientos indagados y consensuados, de manera de hacer un aporte al ámbito escolar, contribuyendo por ende al cumplimiento de los objetivos propuestos por el Ministerio de Educación de Chile. Las etapas contempladas en la investigación permitieron ir explorando y sistematizando los aportes de los participantes destacando aquellos acuerdos asociados a los comportamientos evidenciados y que son frecuentes en el centro educativo (disruptivos, psicológico o físico), con el objeto de incorporarlos en la política reguladora de las conductas escolares y conformar con ello un marco conductual que aporte a una convivencia armoniosa en el centro educativo

    Differences in gait patterns, pain, function and quality of life between males and females with knee osteoarthritis: a clinical trial

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    <p>Abstract</p> <p>Background</p> <p>The aim of this study was to gain a deeper understanding of the gender differences in knee osteoarthritis (OA) by evaluating the differences in gait spatio-temporal parameters and the differences in pain, quality of life and function between males and females suffering from knee OA.</p> <p>Methods</p> <p>49 males and 85 females suffering from bilateral medial compartment knee OA participated in this study. Each patient underwent a computerized gait test and completed the WOMAC questionnaire and the SF-36 health survey. Independent t-tests were performed to examine the differences between males and females in age, BMI, spatio-temporal parameters, the WOMAC questionnaire and the SF-36 health survey.</p> <p>Results</p> <p>Males and females had different gait patterns. Although males and females walked at the same walking speed, cadence and step length, they presented significant differences in the gait cycle phases. Males walked with a smaller stance and double limb support, and with a larger swing and single limb support compared to females. In addition, males walked with a greater toe out angle compared to females. While significant differences were not found in the WOMAC subscales, females consistently reported higher levels of pain and disability.</p> <p>Conclusion</p> <p>The spatio-temporal differences between genders may suggest underlying differences in the gait strategies adopted by males and females in order to reduce pain and cope with the loads acting on their affected joints, two key aspects of knee OA. These gender effects should therefore be taken into consideration when evaluating patients with knee OA.</p> <p>Trial Registration</p> <p>The study is registered in the NIH clinical trial registration, protocol No. NCT00599729.</p

    An Eccentric Massive Jupiter Orbiting a Subgiant on a 9.5-day Period Discovered in the <i>Transiting Exoplanet Survey Satellite</i> Full Frame Images

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    We report the discovery of TOI-172 b from the Transiting Exoplanet Survey Satellite (TESS) mission, a massive hot Jupiter transiting a slightly evolved G star with a 9.48-day orbital period. This is the first planet to be confirmed from analysis of only the TESS full frame images, because the host star was not chosen as a two-minute cadence target. From a global analysis of the TESS photometry and follow-up observations carried out by the TESS Follow-up Observing Program Working Group, TOI-172 (TIC 29857954) is a slightly evolved star with an effective temperature of T eff = 5645 ± 50 K, a mass of M ⋆ = {1.128}-0.061+0.065 M ⊙, radius of R ⋆ = {1.777}-0.044+0.047 R ⊙, a surface gravity of log g ⋆ = {3.993}-0.028+0.027, and an age of {7.4}-1.5+1.6 {Gyr}. Its planetary companion (TOI-172 b) has a radius of R P = {0.965}-0.029+0.032 R J, a mass of M P = {5.42}-0.20+0.22 M J, and is on an eccentric orbit (e={0.3806}-0.0090+0.0093). TOI-172 b is one of the few known massive giant planets on a highly eccentric short-period orbit. Future study of the atmosphere of this planet and its system architecture offer opportunities to understand the formation and evolution of similar systems

    Another Shipment of Six Short-Period Giant Planets from TESS

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    We present the discovery and characterization of six short-period, transiting giant planets from NASA's Transiting Exoplanet Survey Satellite (TESS) -- TOI-1811 (TIC 376524552), TOI-2025 (TIC 394050135), TOI-2145 (TIC 88992642), TOI-2152 (TIC 395393265), TOI-2154 (TIC 428787891), & TOI-2497 (TIC 97568467). All six planets orbit bright host stars (8.9 <G< 11.8, 7.7 <K< 10.1). Using a combination of time-series photometric and spectroscopic follow-up observations from the TESS Follow-up Observing Program (TFOP) Working Group, we have determined that the planets are Jovian-sized (RP_{P} = 1.00-1.45 RJ_{J}), have masses ranging from 0.92 to 5.35 MJ_{J}, and orbit F, G, and K stars (4753 << Teff_{eff} << 7360 K). We detect a significant orbital eccentricity for the three longest-period systems in our sample: TOI-2025 b (P = 8.872 days, ee = 0.220±0.0530.220\pm0.053), TOI-2145 b (P = 10.261 days, ee = 0.1820.049+0.0390.182^{+0.039}_{-0.049}), and TOI-2497 b (P = 10.656 days, ee = 0.1960.053+0.0590.196^{+0.059}_{-0.053}). TOI-2145 b and TOI-2497 b both orbit subgiant host stars (3.8 << log\log g <<4.0), but these planets show no sign of inflation despite very high levels of irradiation. The lack of inflation may be explained by the high mass of the planets; 5.350.35+0.325.35^{+0.32}_{-0.35} MJ_{\rm J} (TOI-2145 b) and 5.21±0.525.21\pm0.52 MJ_{\rm J} (TOI-2497 b). These six new discoveries contribute to the larger community effort to use {\it TESS} to create a magnitude-complete, self-consistent sample of giant planets with well-determined parameters for future detailed studies.Comment: 20 Pages, 6 Figures, 8 Tables, Accepted by MNRA

    A joint procedural position statement on imaging in cardiac sarcoidosis: from the Cardiovascular and Inflammation & Infection Committees of the European Association of Nuclear Medicine, the European Association of Cardiovascular Imaging, and the American Society of Nuclear Cardiology

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    A TESS Dress Rehearsal: Planetary Candidates and Variables from K2 Campaign 17

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    We produce light curves for all ∼34,000 targets observed with K2 in Campaign 17 (C17), identifying planet candidates, eclipsing binaries, and other periodic variables. The forward-facing direction of the C17 field means follow-up can begin immediately now that the campaign has concluded and interesting targets have been identified. The C17 field has a large overlap with C6, so this latest campaign also offers an infrequent opportunity to study a large number of targets already observed in a previous K2 campaign. The timing of the C17 data release, shortly before science operations begin with the Transiting Exoplanet Survey Satellite (TESS), also lets us exercise some of the tools and methods developed for identification and dissemination of planet candidates from TESS. We find excellent agreement between these results and those identified using only K2-based tools. Among our planet candidates are several planet candidates with sizes <4 R ⊕ and orbiting stars with Kp ≲ 10 (indicating good RV targets of the sort TESS hopes to find) and a Jupiter-sized single-transit event around a star already hosting a 6 day planet candidate

    A Possible Alignment Between the Orbits of Planetary Systems and their Visual Binary Companions

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    Astronomers do not have a complete picture of the effects of wide-binary companions (semimajor axes greater than 100 au) on the formation and evolution of exoplanets. We investigate these effects using new data from Gaia Early Data Release 3 and the Transiting Exoplanet Survey Satellite mission to characterize wide-binary systems with transiting exoplanets. We identify a sample of 67 systems of transiting exoplanet candidates (with well-determined, edge-on orbital inclinations) that reside in wide visual binary systems. We derive limits on orbital parameters for the wide-binary systems and measure the minimum difference in orbital inclination between the binary and planet orbits. We determine that there is statistically significant difference in the inclination distribution of wide-binary systems with transiting planets compared to a control sample, with the probability that the two distributions are the same being 0.0037. This implies that there is an overabundance of planets in binary systems whose orbits are aligned with those of the binary. The overabundance of aligned systems appears to primarily have semimajor axes less than 700 au. We investigate some effects that could cause the alignment and conclude that a torque caused by a misaligned binary companion on the protoplanetary disk is the most promising explanation
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