Strong HI Lyman-α\alpha variations from the 11 Gyr-old host star Kepler-444: a planetary origin ?

Kepler-444 provides a unique opportunity to probe the atmospheric composition and evolution of a compact system of exoplanets smaller than the Earth. Five planets transit this bright K star at close orbital distances, but they are too small for their putative lower atmosphere to be probed at optical/infrared wavelengths. We used the Space Telescope Imaging Spectrograph instrument onboard the Hubble Space Telescope to search for the signature of the planet's upper atmospheres at six independent epochs in the Ly-$\alpha$ line. We detect significant flux variations during the transits of both Kepler-444e and f (~20%), and also at a time when none of the known planets was transiting (~40%). Variability in the transition region and corona of the host star might be the source of these variations. Yet, their amplitude over short time scales (~2-3 hours) is surprisingly strong for this old (11.2+-1.0Gyr) and apparently quiet main-sequence star. Alternatively, we show that the in-transits variations could be explained by absorption from neutral hydrogen exospheres trailing the two outer planets (Kepler-444e and f). They would have to contain substantial amounts of water to replenish such hydrogen exospheres, which would reveal them as the first confirmed ocean-planets. The out-of-transit variations, however, would require the presence of a yet-undetected Kepler-444g at larger orbital distance, casting doubt on the planetary origin scenario. Using HARPS-N observations in the sodium doublet, we derived the properties of two Interstellar Medium clouds along the line-of-sight toward Kepler-444. This allowed us to reconstruct the stellar Ly-$\alpha$ line profile and to estimate the XUV irradiation from the star, which would still allow for a moderate mass loss from the outer planets after 11.2Gyr. Follow-up of the system at XUV wavelengths will be required to assess this tantalizing possibility.Comment: Accepted for publication in A&A Name of the system added to the title in most recent versio

Review of 14 drowning publications based on the Utstein style for drowning

Abstract Background The Utstein style for drowning (USFD) was published in 2003 with the aim of improving drowning research. To support a revision of the USFD, the current study aimed to generate an inventory of the use of the USFD parameters and compare the findings of the publications that have used the USFD. Methods A search in Pubmed, Embase, the Cochrane Library, Web of Science and Scopus was performed to identify studies that used the USFD and were published between 01-10-2003 and 22-03-2015. We also searched in Pubmed, Embase, the Cochrane Library, Web of Science, and Scopus for all publications that cited the two publications containing the original ILCOR advisory statement introducing and recommending the USFD. In total we identified 14 publications by groups that explicitly used elements of the USFD for collecting and reporting their data. Results Of the 22 core and 19 supplemental USFD parameters, 6–19 core (27–86%) and 1–12 (5–63%) supplemental parameters were used; two parameters (5%) have not been used in any publication. Associations with outcome were reported for nine core (41%) and five supplemental (26%) USFD parameters. The USFD publications also identified non-USFD parameters related to outcome: initial cardiac rhythm, time points and intervals during resuscitation, intubation at the drowning scene, first hospital core temperature, serum glucose and potassium, the use of inotropic/vasoactive agents and the Paediatric Index of Mortality 2-score. Conclusions Fourteen USFD based drowning publications have been identified. These publications provide valuable information about the process and quality of drowning resuscitation and confirm that the USFD is helpful for a structured comparison of the outcome of drowning resuscitation

Surviving the storm:manual vs. mechanical chest compressions onboard a lifeboat during bad weather conditions

Objective: It is challenging for rescuers to perform cardiopulmonary resuscitation (CPR) onboard lifeboats, particularly during rough weather. A mechanical chest compression device (MCD) may provide better quality chest compressions. The aim of this study was to compare the quality of chest compressions performed by lifeboat-crewmembers with those of a MCD during rough-sea conditions.Methods: Lifeboat-crewmembers were scheduled to provide compression-onlyCPR on a resuscitation-mannequin during two sets of five 6-min epochs on alifeboat at sea in two different weather-conditions. Simultaneously a MCD wasused for compression-only CPR on another mannequin onboard the lifeboat. Ona third occasion compressions by MCD only were measured due to COVID-19restrictions. The primary outcome variable was the quality of chest compression,evaluated using published variables and standards (mean compression depthand compression frequency, percentage correct compression depth, percentageof not leaning on the thorax, percentage of correct hand placement on thethorax, hands-off-time).Results: Six male lifeboat-crewmembers (mean age 35 years) performed CPRduring two different weather conditions. In weather-conditions one (wind∼6–7 Beaufort/wave-height: 100–150 cm) quality of manual compressions wassignificantly worse than mechanical compressions for mean compression depth(p < 0.05) and compression frequency (p < 0.05), percentage correct compression depth (p < 0.05), percentage of not leaning on the thorax (p < 0.05), and hands off time (p < 0.05). Crewmembers could only perform CPR for a limited time-period (sea-conditions/seasickness) and after one set of five epochs measurements were halted. In weather-condition two (wind ∼9 Beaufort/wave-height ∼200 cm) similar results were found during two epochs, after which measurements were halted (sea-conditions/seasickness). In weather-condition three (wind ∼7 Beaufort/wave-height ∼300–400 cm) MCD compressions were according to resuscitation-guidelines except for three epochs during which the MCD was displaced.Conclusion: Crewmembers were only able to perform chest-compressions for alimited time because of the weather-conditions. The MCD was able to providegood quality chest compressions during all but three epochs during the studyperiod. More research is needed to determine whether MCD-use in real-lifecircumstances improves outcome. Inclusion of data on use of a MCD on lifeboatsshould be considered in future revisions of the USFD and resuscitation guidelines

Detection of Helium in the Atmosphere of the Exo-Neptune HAT-P-11b

The helium absorption triplet at a wavelength of 10,833 \AA\ has been proposed as a way to probe the escaping atmospheres of exoplanets. Recently this feature was detected for the first time using Hubble Space Telescope (HST) WFC3 observations of the hot Jupiter WASP-107b. We use similar HST/WFC3 observations to detect helium in the atmosphere of the hot Neptune HAT-P-11b at the $4\sigma$ confidence level. We compare our observations to a grid of 1D models of hydrodynamic escape to constrain the thermospheric temperatures and mass loss rate. We find that our data are best fit by models with high mass loss rates of $\dot{M} \approx 10^{9}$ - $10^{11}$ g s$^{-1}$. Although we do not detect the planetary wind directly, our data are consistent with the prediction that HAT-P-11b is experiencing hydrodynamic atmospheric escape. Nevertheless, the mass loss rate is low enough that the planet has only lost up to a few percent of its mass over its history, leaving its bulk composition largely unaffected. This matches the expectation from population statistics, which indicate that close-in planets with radii greater than 2 R$_{\oplus}$ form and retain H/He-dominated atmospheres. We also confirm the independent detection of helium in HAT-P-11b obtained with the CARMENES instrument, making this the first exoplanet with the detection of the same signature of photoevaporation from both ground- and space-based facilities.Comment: 12 pages, 9 figures, accepted for publication in ApJ

Return to Baseline After an Interpretation Training as a Dynamic Predictor for Treatment Response in Social Anxiety Disorder

Background: Despite considerable research efforts, consistent predictors of cognitive behavioral therapy (CBT) outcome for social anxiety disorder (SAD) are scarce. A dynamic focus on individual symptom reactivity and resilience patterns may show promise in predicting treatment response. This pilot study is the first to investigate whether rate of return to baseline after a one-session positive interpretation training indicates resilience and predicts CBT-response among individuals with SAD. Method: Participants (N = 39) completed an interpretation bias assessment before and after training, and once a day for three days after the training, followed by a six-week CBT-program. Participants completed SAD-assessments pre-treatment, during treatment, and post-treatment. Return to baseline was operationalized as the individualized slope of negative and positive interpretations across interpretation bias assessments. Results: Intention-to-treat analyses showed no significant relation between both negative and positive interpretation bias and CBT-response. Similarly, for completers-only, most analyses also showed no such relationship. Conclusion: These findings suggest that slower return to baseline as a resilience index does not have predictive value for CBT-outcome in individuals with SAD. Future studies should incorporate experience-sampling to capture subtle changes in interpretation bias.</p

Wind of Change: retrieving exoplanet atmospheric winds from high-resolution spectroscopy

Context. The atmosphere of exoplanets has been studied extensively in recent years, using numerical models to retrieve chemical composition, dynamical circulation or temperature from data. One of the best observational probes in transmission is the sodium doublet, due to its large cross section. However, modelling the shape of the planetary sodium lines has proven to be challenging. Models with different assumptions regarding the atmosphere have been employed to fit the lines in the literature, yet statistically sound direct comparisons of different models are needed to paint a clear picture. Aims. We will compare different wind and temperature patterns and provide a tool to distinguish them driven by their best fit for the sodium transmission spectrum of the hot Jupiter HD 189733b. We parametrise different possible wind patterns already tested in literature and introduce the new option of an upwards driven vertical wind. Methods. We construct a forward model where the wind speed, wind geometry and temperature are injected into the calculation of the transmission spectrum. We embed this forward model in a nested sampling retrieval code to rank the models via their Bayesian evidence. Results. We retrieve a best-fit to the HD 189733b data for vertical upward winds $|\vec{v}_{\mathrm{ver}}(\mathrm{mean})|=40\pm4$ km/s at altitudes above $10^{-6}$ bar. With the current data from HARPS, we cannot distinguish wind patterns for higher pressure atmospheric layers. Conclusions. We show that vertical upwards winds in the upper atmosphere are a possible explanation for the broad sodium signature in hot Jupiters. We highlight other influences on the width of the doublet and explore strong magnetic fields acting on the lower atmosphere as one possible origin of the retrieved wind speed.Comment: 17 pages, 30 figures, accepted for publication in Astronomy & Astrophysics (04.12.2019

Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) I. Detection of hot neutral sodium at high altitudes on WASP-49b

High-resolution optical spectroscopy during the transit of HD 189733b, a prototypical hot Jupiter, allowed the resolution of the Na I D sodium lines in the planet, giving access to the extreme conditions of the planet upper atmosphere. We have undertaken HEARTS, a spectroscopic survey of exoplanet upper atmospheres, to perform a comparative study of hot gas giants and determine how stellar irradiation affect them. Here, we report on the first HEARTS observations of the hot Saturn-mass planet WASP-49b. We observed the planet with the HARPS high-resolution spectrograph at ESO 3.6m telescope. We collected 126 spectra of WASP-49, covering three transits of WASP-49b. We analyzed and modeled the planet transit spectrum, while paying particular attention to the treatment of potentially spurious signals of stellar origin. We spectrally resolve the Na I D lines in the planet atmosphere and show that these signatures are unlikely to arise from stellar contamination. The large contrasts of $2.0\pm0.5\%$ (D$_2$) and $1.8\pm0.7\%$ (D$_1$) require the presence of hot neutral sodium ($2,950^{+400}_{-500}$ K) at high altitudes ($\sim$1.5 planet radius or $\sim$45,000 km). From estimating the cloudiness index of WASP-49b, we determine its atmosphere to be cloud free at the altitudes probed by the sodium lines. WASP-49b is close to the border of the evaporation desert and exhibits an enhanced thermospheric signature with respect to a farther-away planet such as HD 189733b.Comment: Accepted for publication in A&A. 14 page

NIGHT: a compact, near-infrared, high-resolution spectrograph to survey helium in exoplanet systems

Among highly irradiated exoplanets, some have been found to undergo significant hydrodynamic expansion traced by atmospheric escape. To better understand these processes in the context of planetary evolution, we propose NIGHT (the Near-Infrared Gatherer of Helium Transits). NIGHT is a high-resolution spectrograph dedicated to surveying and temporally monitoring He I triplet absorption at 1083nm in stellar and planetary atmospheres. In this paper, we outline our scientific objectives, requirements, and cost-efficient design. Our simulations, based on previous detections and modelling using the current exoplanet population, determine our requirements and survey targets. With a spectral resolution of 70,000 on a 2-meter telescope, NIGHT can accurately resolve the helium triplet and detect 1% peak absorption in 118 known exoplanets in a single transit. Additionally, it can search for three-sigma temporal variations of 0.4% in 66 exoplanets in-between two transits. These are conservative estimates considering the ongoing detections of transiting planets amenable to atmospheric characterisation. We find that instrumental stability at 40m/s, less stringent than for radial velocity monitoring, is sufficient for transmission spectroscopy in He I. As such, NIGHT can utilize mostly off-the-shelf components, ensuring cost-efficiency. A fibre-fed system allows for flexibility as a visitor instrument on a variety of telescopes, making it ideal for follow-up observations after JWST or ground-based detections. Over a few years of surveying, NIGHT could offer detailed insights into the mechanisms shaping the hot Neptune desert and close-in planet population by significantly expanding the statistical sample of planets with known evaporating atmospheres. First light is expected in 2024.Comment: 15 pages, 20 figures, this manuscript has been accepted for publication in MNRAS. This is a pre-copyedited, author-produced PD