| 1. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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| 2. |
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| 3. |
- Barragan, O., et al.
(författare)
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The young HD 73583 (TOI-560) planetary system: two 10-M-circle plus mini-Neptunes transiting a 500-Myr-old, bright, and active K dwarf
- 2022
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 514:2, s. 1606-1627
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Tidskriftsartikel (refereegranskat)abstract
- We present the discovery and characterization of two transiting planets observed by TESS in the light curves of the young and bright (V = 9.67) star HD73583 (TOI-560). We perform an intensive spectroscopic and photometric space- and ground-based follow-up in order to confirm and characterize the system. We found that HD73583 is a young (similar to 500 Myr) active star with a rotational period of 12.08 +/- 0.11 d, and a mass and radius of 0.73 +/- 0.02 M-circle dot and 0.65 +/- 0.02 R-circle dot, respectively. HD 73583 b (P-b = 6.3980420(-0.0000062)(+0.0000067 )d) has a mass and radius of 10.2(-3.1)(+3.4) M-circle plus and 2.79 +/- 0.10 R-circle plus, respectively, which gives a density of 2.58(-0.81)(+0.95) g cm(-3). HD 73583 c (P-c = 18.87974(-0.00074)(+0.00086) d) has a mass and radius of 9.7(-1.7)(+1.8) M-circle plus and 2.39(-0.09)(+0.10) R-circle plus, respectively, which translates to a density of 3.88(-0.80)(+0.91) g cm(-3). Both planets are consistent with worlds made of a solid core surrounded by a volatile envelope. Because of their youth and host star brightness, they both are excellent candidates to perform transmission spectroscopy studies. We expect ongoing atmospheric mass-loss for both planets caused by stellar irradiation. We estimate that the detection of evaporating signatures on H and He would be challenging, but doable with present and future instruments.
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| 4. |
- Cabrera, J., et al.
(författare)
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Transiting exoplanets from the CoRoT space mission: XXVII. CoRoT-28b, a planet orbiting an evolved star, and CoRoT-29b, a planet showing an asymmetric transit
- 2015
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 579
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Tidskriftsartikel (refereegranskat)abstract
- © ESO, 2015. Context. We present the discovery of two transiting extrasolar planets by the satellite CoRoT. Aims. We aim at a characterization of the planetary bulk parameters, which allow us to further investigate the formation and evolution of the planetary systems and the main properties of the host stars. Methods. We used the transit light curve to characterize the planetary parameters relative to the stellar parameters. The analysis of HARPS spectra established the planetary nature of the detections, providing their masses. Further photometric and spectroscopic ground-based observations provided stellar parameters (log g, Teff, vsini) to characterize the host stars. Our model takes the geometry of the transit to constrain the stellar density into account, which when linked to stellar evolutionary models, determines the bulk parameters of the star. Because of the asymmetric shape of the light curve of one of the planets, we had to include the possibility in our model that the stellar surface was not strictly spherical. Results. We present the planetary parameters of CoRoT-28b, a Jupiter-sized planet (mass 0.484 ± 0.087 MJup; radius 0.955 ± 0.066 RJup) orbiting an evolved star with an orbital period of 5.208 51 ± 0.000 38 days, and CoRoT-29b, another Jupiter-sized planet (mass 0.85 ± 0.20 MJup; radius 0.90 ± 0.16 RJup) orbiting an oblate star with an orbital period of 2.850 570 ± 0.000 006 days. The reason behind the asymmetry of the transit shape is not understood at this point. Conclusions. These two new planetary systems have very interesting properties and deserve further study, particularly in the case of the star CoRoT-29.
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| 5. |
- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 6. |
- Csizmadia, S., et al.
(författare)
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Transiting exoplanets from the CoRoT space mission XXVIII. CoRoT-33b, an object in the brown dwarf desert with 2:3 commensurability with its host star
- 2015
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 584
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Tidskriftsartikel (refereegranskat)abstract
- We report the detection of a rare transiting brown dwarf with a mass of 59 M-Jup and radius of 1.1 R-Jup around the metal-rich, [Fe/H] = +0.44, G9V star CoRoT-33. The orbit is eccentric (e = 0.07) with a period of 5.82 d. The companion, CoRoT-33b, is thus a new member in the so-called brown dwarf desert. The orbital period is within 3% to a 3:2 resonance with the rotational period of the star. CoRoT-33b may be an important test case for tidal evolution studies. The true frequency of brown dwarfs close to their host stars (P
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| 7. |
- Bordé, P., et al.
(författare)
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Transiting exoplanets from the CoRoT space mission: XXIX. The hot Jupiters CoRoT-30 b and CoRoT-31 b
- 2020
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 635
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Tidskriftsartikel (refereegranskat)abstract
- We report the discovery as well as the orbital and physical characterizations of two new transiting giant exoplanets, CoRoT-30 b and CoRoT-31 b, with the CoRoT space telescope. Methods. We analyzed two complementary data sets: photometric transit light curves measured by CoRoT, and radial velocity curves measured by the HARPS spectrometer. To derive the absolute masses and radii of the planets, we modeled the stars from available magnitudes and spectra. Results. We find that CoRoT-30 b is a warm Jupiter on a close-to-circular 9.06-day orbit around a G3V star with a semi-major axis of about 0.08 AU. It has a radius of 1.01 ± 0.08 RJ, a mass of 2.90 ± 0.22 MJ, and therefore a mean density of 3.45 ± 0.65 g cm-3. The hot Jupiter CoRoT-31 b is on a close-to-circular 4.63-day orbit around a G2 IV star with a semi-major axis of about 0.05 AU. It has a radius of 1.46 ± 0.30 RJ, a mass of 0.84 ± 0.34 MJ, and therefore a mean density of 0.33 ± 0.18 g cm-3. Conclusions. Neither system seems to support the claim that stars hosting planets are more depleted in lithium. The radii of both planets are close to that of Jupiter, but they differ in mass; CoRoT-30 b is ten times denser than CoRoT-31 b. The core of CoRoT-30 b would weigh between 15 and 75 Earth masses, whereas relatively weak constraints favor no core for CoRoT-31 b. In terms of evolution, the characteristics of CoRoT-31 b appear to be compatible with the high-eccentricity migration scenario, which is not the case for CoRoT-30 b. The angular momentum of CoRoT-31 b is currently too low for the planet to evolve toward synchronization of its orbital revolution with stellar rotation, and the planet will slowly spiral-in while its host star becomes a red giant. CoRoT-30 b is not synchronized either: it looses angular momentum owing to stellar winds and is expected reach steady state in about 2 Gyr. CoRoT-30 and 31, as a pair, are a truly remarkable example of diversity in systems with hot Jupiters.
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| 8. |
- Eisner, N. L., et al.
(författare)
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Planet Hunters Tess I: TOI 813, a subgiant hosting a transiting Saturn-sized planet on an 84-day orbit
- 2020
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 494:1, s. 750-763
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Forskningsöversikt (refereegranskat)abstract
- We report on the discovery and validation of TOI 813 b (TIC55525572b), a transiting exoplanet identified by citizen scientists in data from NASA's Transiting Exoplanet Survey Satellite (TESS) and the first planet discovered by the Planet Hunters TESS project. The host star is a bright (V = 10.3 mag) subgiant (R* = 1.94 R☉, M☉ = 1.32 M☉). It was observed almost continuously by TESS during its first year of operations, during which time four individual transit events were detected. The candidate passed all the standard light curve-based vetting checks, and ground-based follow-up spectroscopy and speckle imaging enabled us to place an upper limit of 2 MJup (99 per cent confidence) on the mass of the companion, and to statistically validate its planetary nature. Detailed modelling of the transits yields a period of 83.8911+0.0027-0.0031 d, a planet radius of 6.71 ± 0.38 R⊕ and a semimajor axis of 0.423+0031-0.037 AU. The planet's orbital period combined with the evolved nature of the host star places this object in a relatively underexplored region of parameter space. We estimate that TOI 813 b induces a reflex motion in its host star with a semi-amplitude of ∼6 m s−1, making this a promising system to measure the mass of a relatively long-period transiting planet.
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| 9. |
- Bonomo, A. S., et al.
(författare)
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A deeper view of the CoRoT-9 planetary system A small non-zero eccentricity for CoRoT-9b likely generated by planet-planet scattering
- 2017
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 603, s. A43-
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Tidskriftsartikel (refereegranskat)abstract
- CoRoT-9b is one of the rare long-period (P = 95 : 3 days) transiting giant planets with a measured mass known to date. We present a new analysis of the CoRoT-9 system based on five years of radial-velocity (RV) monitoring with HARPS and three new space-based transits observed with CoRoT and Spitzer. Combining our new data with already published measurements we redetermine the CoRoT-9 system parameters and find good agreement with the published values. We uncover a higher significance for the small but non-zero eccentricity of CoRoT-9b (e = 0 : 133(-0.037)(+0.042)) and find no evidence for additional planets in the system. We use simulations of planet-planet scattering to show that the eccentricity of CoRoT-9b may have been generated by an instability in which a similar to 50 M-circle plus planet was ejected from the system. This scattering would not have produced a spin-orbit misalignment, so we predict that the CoRoT-9b orbit should lie within a few degrees of the initial plane of the protoplanetary disk. As a consequence, any significant stellar obliquity would indicate that the disk was primordially tilted.
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| 10. |
- Barragán, O., et al.
(författare)
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Radial velocity confirmation of K2-100b: A young, highly irradiated, and low-density transiting hot Neptune
- 2019
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 490:1, s. 698-708
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Tidskriftsartikel (refereegranskat)abstract
- We present a detailed analysis of HARPS-N radial velocity observations of K2-100, a young and active star in the Praesepe cluster, which hosts a transiting planet with a period of 1.7 d. We model the activity-induced radial velocity variations of the host star with a multidimensional Gaussian Process framework and detect a planetary signal of 10.6 ± 3.0 m s−1, which matches the transit ephemeris, and translates to a planet mass of 21.8 ± 6.2 M. We perform a suite of validation tests to confirm that our detected signal is genuine. This is the first mass measurement for a transiting planet in a young open cluster. The relatively low density of the planet, 2.04+−006661 g cm−3, implies that K2-100b retains a significant volatile envelope. We estimate that the planet is losing its atmosphere at a rate of 1011–1012 g s−1 due to the high level of radiation it receives from its host star.
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| 11. |
- Canocchi, Gloria, 1998-, et al.
(författare)
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Discovering planets with PLATO : Comparison of algorithms for stellar activity filtering
- 2023
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 672
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Tidskriftsartikel (refereegranskat)abstract
- Context. To date, stellar activity is one of the main limitations in detecting small exoplanets via the transit photometry technique. Since this activity is enhanced in young stars, traditional filtering algorithms may severely underperform in attempting to detect such exoplanets, with shallow transits often obscured by the photometric modulation of the light curve.Aims. This paper aims to compare the relative performances of four algorithms developed by independent research groups specifically for the filtering of activity in the light curves of young active stars, prior to the search for planetary transit signals: Notch and LOCoR (N&L), Young Stars Detrending (YSD), K2 Systematics Correction (K2SC), and VARLET. Our comparison also includes the two best-performing algorithms implemented in the Wōtan package: Tukey’s biweight and Huber spline algorithms.Methods. For this purpose, we performed a series of injection-retrieval tests of planetary transits of different types, from Jupiter down to Earth-sized planets, moving both on circular and eccentric orbits. These experiments were carried out over a set of 100 realistically simulated light curves of both quiet and active solar-like stars (i.e., F and G types) that will be observed by the ESA Planetary Transits and Oscillations of stars (PLATO) space telescope, starting 2026.Results. From the experiments for transit detections, we found that N&L is the best choice in many cases, since it misses the lowest number of transits. However, this algorithm is shown to underperform when the planetary orbital period closely matches the stellar rotation period, especially in the case of small planets for which the biweight and VARLET algorithms work better. Moreover, for light curves with a large number of data-points, the combined results of two algorithms, YSD and Huber spline, yield the highest recovery percentage. Filtering algorithms allow us to obtain a very precise estimate of the orbital period and the mid-transit time of the detected planets, while the planet-to-star radius is underestimated most of the time, especially in cases of grazing transits or eccentric orbits. A refined filtering that takes into account the presence of the planet is thus compulsory for proper planetary characterization analyses.
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| 12. |
- Deleuil, M., et al.
(författare)
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Planets, candidates, and binaries from the CoRoT/Exoplanet programme: The CoRoT transit catalogue
- 2018
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 619
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Tidskriftsartikel (refereegranskat)abstract
- The CoRoT space mission observed 163 665 stars over 26 stellar fields in the faint star channel. The exoplanet teams detected a total of 4123 transit-like features in the 177 454 light curves. We present the complete re-analysis of all these detections carried out with the same softwares so that to ensure their homogeneous analysis. Although the vetting process involves some human evaluation, it also involves a simple binary flag system over basic tests: Detection significance, presence of a secondary, difference between odd and even depths, colour dependence, V-shape transit, and duration of the transit. We also gathered the information from the large accompanying ground-based programme carried out on the planet candidates and checked how useful the flag system could have been at the vetting stage of the candidates. From the initial list of transit-like features, we identified and separated 824 false alarms of various kind, 2269 eclipsing binaries among which 616 are contact binaries and 1653 are detached ones, 37 planets and brown dwarfs, and 557 planet candidates. We provide the catalogue of all these transit-like features, including false alarms. For the planet candidates, the catalogue gives not only their transit parameters but also the products of their light curve modelling: Reduced radius, reduced semi-major axis, and impact parameter, together with a summary of the outcome of follow-up observations when carried out and their current status. For the detached eclipsing binaries, the catalogue provides, in addition to their transit parameters, a simple visual classification. Among the planet candidates whose nature remains unresolved, we estimate that eight (within an error of three) planets are still to be identified. After correcting for geometric and sensitivity biases, we derived planet and brown dwarf occurrences and confirm disagreements with Kepler estimates, as previously reported by other authors from the analysis of the first runs: Small-size planets with orbital period less than ten days are underabundant by a factor of three in the CoRoT fields whereas giant planets are overabundant by a factor of two. These preliminary results would however deserve further investigations using the recently released CoRoT light curves that are corrected of the various instrumental effects and a homogeneous analysis of the stellar populations observed by the two missions.
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| 13. |
- Hebb, L., et al.
(författare)
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MML 53 : a new low-mass, pre-main sequence eclipsing binary in the Upper Centaurus-Lupus region discovered by SuperWASP
- 2010
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 522:2, s. A37-
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Tidskriftsartikel (refereegranskat)abstract
- We announce the discovery of a new low-mass, pre-main sequence eclipsing binary, MML 53. Previous observations of MML 53 found it to be a pre-main sequence spectroscopic multiple associated with the 15-22 Myr Upper Centaurus-Lupus cluster. We identify the object as an eclipsing binary for the first time through the analysis of multiple seasons of time series photometry from the SuperWASP transiting planet survey. Re-analysis of a single archive spectrum shows MML 53 to be a spatially unresolved triple system of young stars which all exhibit significant lithium absorption. Two of the components comprise an eclipsing binary with period, P = 2.097891(6) +/- 0.000005 and mass ratio, q similar to 0.8. Here, we present the analysis of the discovery data.
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| 14. |
- Frisch, M, et al.
(författare)
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Cultural bias in the AAP's 2012 Technical Report and Policy Statement on male circumcision
- 2013
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Ingår i: Pediatrics. - : American Academy of Pediatrics (AAP). - 1098-4275 .- 0031-4005. ; 131:4, s. 796-800
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Tidskriftsartikel (refereegranskat)abstract
- The American Academy of Pediatrics recently released its new Technical Report and Policy Statement on male circumcision, concluding that current evidence indicates that the health benefits of newborn male circumcision outweigh the risks. The technical report is based on the scrutiny of a large number of complex scientific articles. Therefore, while striving for objectivity, the conclusions drawn by the 8 task force members reflect what these individual physicians perceived as trustworthy evidence. Seen from the outside, cultural bias reflecting the normality of nontherapeutic male circumcision in the United States seems obvious, and the report’s conclusions are different from those reached by physicians in other parts of the Western world, including Europe, Canada, and Australia. In this commentary, a different view is presented by non–US-based physicians and representatives of general medical associations and societies for pediatrics, pediatric surgery, and pediatric urology in Northern Europe. To these authors, only 1 of the arguments put forward by the American Academy of Pediatrics has some theoretical relevance in relation to infant male circumcision; namely, the possible protection against urinary tract infections in infant boys, which can easily be treated with antibiotics without tissue loss. The other claimed health benefits, including protection against HIV/AIDS, genital herpes, genital warts, and penile cancer, are questionable, weak, and likely to have little public health relevance in a Western context, and they do not represent compelling reasons for surgery before boys are old enough to decide for themselves.
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| 15. |
- Grandjean, A., et al.
(författare)
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Constraining the properties of HD 206893 B A combination of radial velocity, direct imaging, and astrometry data
- 2019
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 627
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Tidskriftsartikel (refereegranskat)abstract
- Context. High contrast imaging enables the determination of orbital parameters for substellar companions (planets, brown dwarfs) from the observed relative astrometry and the estimation of model and age-dependent masses from their observed magnitudes or spectra. Combining astrometric positions with radial velocity gives direct constraints on the orbit and on the dynamical masses of companions. A brown dwarf was discovered with the VLT/SPHERE instrument at the Very Large Telescope (VLT) in 2017, which orbits at similar to 11 au around HD 206893. Its mass was estimated between 12 and 50 M-J from evolutionary models and its photometry. However, given the significant uncertainty on the age of the system and the peculiar spectrophotometric properties of the companion, this mass is not well constrained. Aims. We aim at constraining the orbit and dynamical mass of HD 206893 B. Methods. We combined radial velocity data obtained with HARPS spectra and astrometric data obtained with the high contrast imaging VLT/SPHERE and VLT/NaCo instruments, with a time baseline less than three years. We then combined those data with astrometry data obtained by HIPPARCOS and Gaia with a time baseline of 24 yr. We used a Markov chain Monte Carlo approach to estimate the orbital parameters and dynamical mass of the brown dwarf from those data. Results. We infer a period between 21 and 33 yr and an inclination in the range 20-41 degrees from pole-on from HD 206893 B relative astrometry. The RV data show a significant RV drift over 1.6 yr. We show that HD 206893 B cannot be the source of this observed RV drift as it would lead to a dynamical mass inconsistent with its photometry and spectra and with HIPPARCOS and Gaia data. An additional inner (semimajor axis in the range 1.4-2.6 au) and massive (similar to 15 M-J) companion is needed to explain the RV drift, which is compatible with the available astrometric data of the star, as well as with the VLT/SPHERE and VLT/NaCo nondetection.
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| 16. |
- Lottman, Henri B., et al.
(författare)
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Long-term effects of dextranomer endoscopic injections for treatment of urinary incontinence : an update of a prospective study of 31 patients
- 2006
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Ingår i: Journal of Urology. - 0022-5347 .- 1527-3792. ; 175:4, s. 1485-9
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: A prospective study was initiated 7 years previously to assess the efficacy of endoscopic dextranomer based implants for pediatric structural incontinence. Preliminary results revealed that at 3 years 50% of the patients were either dry or significantly improved. We report long-term results in the same cohort of patients. MATERIALS AND METHODS: A total of 33 children and adolescents 5 to 18 years old with severe incontinence due to sphincteric incompetence (exstrophy-epispadias complex in 13, neuropathic bladder in 16, bilateral ectopic ureter in 4) were enrolled. Of the patients 13 underwent 2 and 4 underwent 3 treatment sessions to achieve a definitive result. Mean injected volume was 3.9 ml (range 1.6 to 12) per session. At each evaluation patients were considered cured (dryness interval 4 hours), significantly improved (minimal incontinence requiring no more than 1 pad daily and no further treatment required) or treatment failures (no significant improvement). Videourodynamics were used to study the evolution of the bladder capacity, activity and compliance. A total of 31 patients were followed 3 to 7 years after the last injection. RESULTS: At 3 years after treatment 15 of 30 patients (50%) were dry or improved. One patient who had leakage after 3 years of dryness due to bladder deterioration subsequently underwent ileocystoplasty. At 4 years 12 of 25 patients (48%) were dry or improved. At 5 years 9 of 21 patients (43%) were dry, as were 4 of 11 (36%) at 6 years and 2 of 5 (40%) at 7 years of followup. The success rate according to pathological evaluation was comparable in neuropathic bladders (7 of 14, or 50%), exstrophy (3 of 6, or 50%) and epispadias (3 of 7, or 43%). Of 12 patients who underwent bladder neck plasty before the injection of bulking agent 7 (58%) were either dry or improved. The success rate was higher in males (13 of 23, or 57%) than in females (3 of 8, or 38%). Also, at puberty 2 males who were improved became dry. Bladder capacity increased in 12 of 18 initially small bladders and remained normal and stable in 9, while 4 initially dry patients had development of recurrent leakage secondary to bladder deterioration and underwent augmentation. Otherwise, there were no long-term side effects observed related to the injection of the bulking agent. CONCLUSIONS: Endoscopic treatment of severe organic urinary incontinence with dextranomer is durable for up to 7 years of followup in 40% of the patients.
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