342 research outputs found
Unveiling the internal structure and formation history of the three planets transiting HIP 29442 (TOI-469) with CHEOPS
Multiplanetary systems spanning the radius valley are ideal testing grounds for exploring the different proposed explanations for the observed bimodality in the radius distribution of close-in exoplanets. One such system is HIP 29442 (TOI-469), an evolved K0V star hosting two super-Earths and one sub-Neptune. We observed HIP 29442 with CHEOPS for a total of 9.6 days, which we modelled jointly with two sectors of TESS data to derive planetary radii of 3.410 ± 0.046, 1.551 ± 0.045, and 1.538 ± 0.049 R⊕ for planets b, c, and d, which orbit HIP 29442 with periods of 13.6, 3.5, and 6.4 days, respectively. For planet d this value deviates by more than 3σ from the median value reported in the discovery paper, leading us to conclude that caution is required when using TESS photometry to determine the radii of small planets with low per-transit signal-to-noise ratios and large gaps between observations. Given the high precision of these new radii, combining them with published RVs from ESPRESSO and HIRES provides us with ideal conditions to investigate the internal structure and formation pathways of the planets in the system. We introduced the publicly available code plaNETic, a fast and robust neural network-based Bayesian internal structure modelling framework. We then applied hydrodynamic models to explore the upper atmospheric properties of these inferred structures. Finally, we identified planetary system analogues in a synthetic population generated with the Bern model for planet formation and evolution. Based on this analysis, we find that the planets likely formed on opposing sides of the water iceline from a protoplanetary disk with an intermediate solid mass. We finally report that the observed parameters of the HIP 29442 system are compatible with a scenario where the second peak in the bimodal radius distribution corresponds to sub-Neptunes with a pure H/He envelope and with a scenario with water-rich sub-Neptunes
Phase II study of capecitabine and oxaliplatin given prior to and concurrently with preoperative pelvic radiotherapy in patients with locally advanced rectal cancer
This multicentre phase II study evaluated the efficacy and safety of preoperative capecitabine plus oxaliplatin and radiotherapy (RT) in patients with locally advanced rectal cancer (T3/T4 rectal adenocarcinoma with or without nodal involvement). Treatment consisted of one cycle of XELOX (capecitabine 1000 mg m−2 bid on days 1–14 and oxaliplatin 130 mg m−2 on day 1), followed by RT (1.8 Gy fractions 5 days per week for 5 weeks) plus CAPOX (capecitabine 825 mg m−2 bid on days 22–35 and 43–56, and oxaliplatin 50 mg m−2 on days 22, 29, 43 and 50). Surgery was recommended 5 weeks after completion of chemoradiotherapy. The primary end point was pathological complete tumour response (pCR). Sixty patients were enrolled. In the intent-to-treat population, the pCR rate was 23% (95% CI: 13–36%). 58 patients underwent surgery; R0 resection was achieved in 57 (98%) patients, including all 5 patients with T4 tumours. Sphincter preservation was achieved in 49 (84%) patients. Tumour and/or nodal downstaging was observed in 39 (65%) patients. The most common grade 3/4 adverse events were diarrhoea (20%) and lymphocytopaenia (43%). Preoperative capecitabine, oxaliplatin and RT achieved encouraging rates of pCR, R0 resection, sphincter preservation and tumour downstaging in patients with locally advanced rectal cancer
CHEOPS in-flight performance: A comprehensive look at the first 3.5 yr of operations
Context. Since the discovery of the first exoplanet almost three decades ago, the number of known exoplanets has increased dramatically. By beginning of the 2000s it was clear that dedicated facilities to advance our studies in this field were needed. The CHaracterising ExOPlanet Satellite (CHEOPS) is a space telescope specifically designed to monitor transiting exoplanets orbiting bright stars. In September 2023, CHEOPS completed its nominal mission duration of 3.5 yr and remains in excellent operational conditions. As a testament to this, the mission has been extended until the end of 2026. Aims. Scientific and instrumental data have been collected throughout in-orbit commissioning and nominal operations, enabling a comprehensive analysis of the mission’s performance. In this article, we present the results of this analysis with a twofold goal. First, we aim to inform the scientific community about the present status of the mission and what can be expected as the instrument ages. Secondly, we intend for this publication to serve as a legacy document for future missions, providing insights and lessons learned from the successful operation of CHEOPS. Methods. To evaluate the instrument performance in flight, we developed a comprehensive monitoring and characterisation (M&C) programme. It consists of dedicated observations that allow us to characterise the instrument’s response and continuously monitor its behaviour. In addition to the standard collection of nominal science and housekeeping data, these observations provide valuable input for detecting, modelling, and correcting instrument systematics, discovering and addressing anomalies, and comparing the instrument’s actual performance with expectations. Results. The precision of the CHEOPS measurements has enabled the mission objectives to be met and exceeded. The satellite’s performance remains stable and reliable, ensuring accurate data collection throughout its operational life. Careful modelling of the instrumental systematics allows the data quality to be significantly improved during the light curve analysis phase, resulting in more precise scientific measurements. Conclusions. CHEOPS is compliant with the driving scientific requirements of the mission. Although visible, the ageing of the instrument has not affected the mission’s performance. The satellite’s capabilities remain robust, and we are confident that we will continue to acquire high-quality data during the mission extension.Fil: Fortier, Andrés. University of Bern; Suiza. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Simon, A. E.. University of Bern; SuizaFil: Broeg, C.. University of Bern; SuizaFil: Olofsson, G.. Stockholms Universitet. Departamento de Astronomia; SueciaFil: Deline, A.. Universidad de Ginebra; SuizaFil: Wilson, T. G.. University of Warwick; Reino UnidoFil: Maxted, P. F. L.. Keele University.; Reino UnidoFil: Brandeker, A.. Stockholms Universitet. Departamento de Astronomia; SueciaFil: Collier Cameron, A.. University of St. Andrews; Reino UnidoFil: Beck, M.. Universidad de Ginebra; SuizaFil: Bekkelien, A.. Universidad de Ginebra; SuizaFil: Billot, N.. Universidad de Ginebra; SuizaFil: Bonfanti, A.. Austrian Academy Of Sciences (oaw);Fil: Bruno, G.. Inaf-catania Astrophysical Observatory; ItaliaFil: Cabrera, J.. German Aerospace Center.; AlemaniaFil: Delrez, L.. Université de Liège; BélgicaFil: Demory, Brice Olivier. University of Bern; SuizaFil: Futyan, D.. Universidad de Ginebra; SuizaFil: Florén, H. G.. Stockholms Universitet. Departamento de Astronomia; SueciaFil: Günther, M. N.. Agencia Espacial Europea; EspañaFil: Heitzmann, A.. Universidad de Ginebra; SuizaFil: Hoyer, S.. Centre National de la Recherche Scientifique; FranciaFil: Isaak, K. G.. Agencia Espacial Europea; EspañaFil: Sousa, S. G.. Aix Marseille Université; Francia. Centre National de la Recherche Scientifique; FranciaFil: Stalport, M.. Research Centre For Astronomy And Earth Sciences; Hungría. Université de Liège; BélgicaFil: Petrucci, Romina Paola. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Villaver, E.. Universidad de La Laguna; España. Instituto de Astrofísica de Canarias; EspañaFil: Vinkó, J.. Research Centre for Astronomy and Earth Sciences; Hungría. ELTE Eötvös Loránd University; Hungría. University of Szeged; HungríaFil: Walton, N. A.. University of Cambridge; Estados UnidosFil: Wells, R.. University of Bern; SuizaFil: Wolter, D.. Institute of Planetary Research; Alemani
TOI-3362b: A Proto Hot Jupiter Undergoing High-Eccentricity Tidal Migration
High-eccentricity tidal migration is a possible way for giant planets to be placed in short-period orbits. If this happens often, one would expect to catch proto hot Jupiters on highly elliptical orbits undergoing high-eccentricity tidal migration. As of yet, few such systems have been discovered. Here, we introduce TOI-3362b (TIC-464300749b), an 18.1 day, 5 MJup planet orbiting a main-sequence F-type star that is likely undergoing high-eccentricity tidal migration. The orbital eccentricity is 0.815 (+0.023)/(-0.032). With a semimajor axis of 0.153 (+0.002)/(-0.003) au, the planet\u27s orbit is expected to shrink to a final orbital radius of 0.051 (+0.008)/(-0.006) au after complete tidal circularization. Several mechanisms could explain the extreme value of the planet\u27s eccentricity, such as planet–planet scattering and secular interactions. Such hypotheses can be tested with follow-up observations of the system, e.g., measuring the stellar obliquity and searching for companions in the system with precise, long-term radial-velocity observations. The variation in the planet\u27s equilibrium temperature as it orbits the host star and the tidal heating at periapse make this planet an intriguing target for atmospheric modeling and observation. Because the planet\u27s orbital period of 18.1 days is near the limit of TESS\u27s period sensitivity, even a few such discoveries suggest that proto hot Jupiters may be quite common
The K+ Channel Opener 1-EBIO Potentiates Residual Function of Mutant CFTR in Rectal Biopsies from Cystic Fibrosis Patients
BACKGROUND: The identification of strategies to improve mutant CFTR function remains a key priority in the development of new treatments for cystic fibrosis (CF). Previous studies demonstrated that the K⁺ channel opener 1-ethyl-2-benzimidazolone (1-EBIO) potentiates CFTR-mediated Cl⁻ secretion in cultured cells and mouse colon. However, the effects of 1-EBIO on wild-type and mutant CFTR function in native human colonic tissues remain unknown. METHODS: We studied the effects of 1-EBIO on CFTR-mediated Cl⁻ secretion in rectal biopsies from 47 CF patients carrying a wide spectrum of CFTR mutations and 57 age-matched controls. Rectal tissues were mounted in perfused micro-Ussing chambers and the effects of 1-EBIO were compared in control tissues, CF tissues expressing residual CFTR function and CF tissues with no detectable Cl⁻ secretion. RESULTS: Studies in control tissues demonstrate that 1-EBIO activated CFTR-mediated Cl⁻ secretion in the absence of cAMP-mediated stimulation and potentiated cAMP-induced Cl⁻ secretion by 39.2±6.7% (P<0.001) via activation of basolateral Ca²⁺-activated and clotrimazole-sensitive KCNN4 K⁺ channels. In CF specimens, 1-EBIO potentiated cAMP-induced Cl⁻ secretion in tissues with residual CFTR function by 44.4±11.5% (P<0.001), but had no effect on tissues lacking CFTR-mediated Cl⁻ conductance. CONCLUSIONS: We conclude that 1-EBIO potentiates Cl⁻secretion in native CF tissues expressing CFTR mutants with residual Cl⁻ channel function by activation of basolateral KCNN4 K⁺ channels that increase the driving force for luminal Cl⁻ exit. This mechanism may augment effects of CFTR correctors and potentiators that increase the number and/or activity of mutant CFTR channels at the cell surface and suggests KCNN4 as a therapeutic target for CF
ATREIDES:I. Embarking on a trek across the exo-Neptunian landscape with the TOI-421 system
Thedistribution of close-in exoplanets is shaped by a complex interplay betweenatmospheric and dynamical processes. The Desert, Ridge, and Savanna(respectively a lack, overoccurence, and mild deficit of Neptunes withincreasing periods) illustrate the sensitivity of these worlds to suchprocesses, making them ideal targets to disentangle their roles. Determininghow many Neptunes are brought close-in by early disk-driven migration (DDM;expected to maintain primordial spin-orbit alignment) or late high-eccentricitytidal migration (HEM; expected to generate large misalignments) is essential tounderstanding how much atmosphere they lost. In this paper, we propose aunified view of the exo-Neptunian landscape to guide its exploration andspeculate that the Ridge is a hot spot for evolutionary processes. Low-densityNeptunes would mainly undergo DDM, becoming fully eroded at shorter periodsthan the Ridge. This is in contrast to denser Neptunes, which would be broughtto the Ridge and Desert by HEM. We embark on this exploration via the ATREIDES(Ancestry, Traits, and Relations of Exoplanets Inhabiting the Desert Edges andSavanna) collaboration, which relies on spectroscopic and photometricobservations of ~60 close-in Neptunes, their reduction with robust pipelines,and their interpretation through internal structure, atmospheric, andevolutionary models. We carried out a systematic Rossiter-McLaughlin censuswith VLT/ESPRESSO to measure the distribution of 3D spin-orbit angles,correlate its shape with the system properties (orbit, density, evaporation),and thus relate the fraction of aligned-misaligned Neptunian systems to DDM,HEM, and atmospheric erosion. The first ATREIDES target, TOI-421 c, lies in theSavanna with a neighboring sub-Neptune TOI-421 b. We measured for the firsttime their 3D spin-orbit angles (ψb = 57−15+11∘; ψc = 44.9−4.1+4.4∘). Together with the eccentricity and possibly large mutualinclination of their orbits, this hints at a chaotic dynamical origin thatcould result from DDM followed by HEM. Our program will provide the communitywith a wealth of constraints for formation and evolution models, and we welcomecollaborations that will contribute to pushing our understanding of theexo-Neptunian landscape forward.</p
Detailed cool star flare morphology with CHEOPS and TESS
Context. White-light stellar flares are proxies for some of the most
energetic types of flares, but their triggering mechanism is still poorly
understood. As they are associated with strong X and UV emission, their study
is particularly relevant to estimate the amount of high-energy irradiation onto
the atmospheres of exoplanets, especially those in their stars' habitable zone.
Aims. We used the high-cadence, high-photometric capabilities of the CHEOPS and
TESS space telescopes to study the detailed morphology of white-light flares
occurring in a sample of 130 late-K and M stars, and compared our findings with
results obtained at a lower cadence. We developed dedicated software for this
purpose. Results. Multi-peak flares represent a significant percentage
(\%) of the detected outburst events. Our findings suggest that
high-impulse flares are more frequent than suspected from lower-cadence data,
so that the most impactful flux levels that hit close-in exoplanets might be
more time-limited than expected. We found significant differences in the
duration distributions of single-peak and complex flare components, but not in
their peak luminosity. A statistical analysis of the flare parameter
distributions provides marginal support for their description with a log-normal
instead of a power-law function, leaving the door open to several flare
formation scenarios. We tentatively confirmed previous results about
quasi-periodic pulsations in high-cadence photometry, report the possible
detection of a pre-flare dip, and did not find hints of photometric variability
due to an undetected flare background. Conclusions. The high-cadence study of
stellar hosts might be crucial to evaluate the impact of their flares on
close-in exoplanets, as their impulsive phase emission might otherwise be
incorrectly estimated. Future telescopes such as PLATO and Ariel will help in
this respect.Comment: 28 pages, 25 figures, 4 tables, to be published in Astronomy &
Astrophysic
- …
