109 research outputs found
The Châtelperronian of Germolles (Grotte de la Verpillière I, Mellecey, Saône-et-Loire, France)
The Grotte de la Verpillière I in Germolles (Saône-et-Loire, France) has yielded an archaeological sequence from the Middle Palaeolithic to the Gravettian period. This contribution focusses on the Châtelperronian lithic industry, covering 150 years of research. From a techno-typological point of view, all known lithic objects presumably dating to this period are subject of this investigation. This study includes in-situ observations of Châtelperronian layers, as part of our own recent excavations. The lithic assemblage is put into context with other Châtelperronian samples in Southern Burgundy and Eastern France
Le Châtelperronien de Germolles (Grotte de La Verpillière I, commune de Mellecey, Saône-et-Loire, France)
La grotte de La Verpillière à Germolles, commune de Mellecey (Saône-et-Loire), a produit une séquence archéologique allant du Paléolithique moyen jusqu’au Gravettien. Cette contribution se focalise sur l’industrie lithique châtelperronienne, en prenant en considération 150 ans de recherches dans la cavité. D’un point de vue techno- et typologique, cette étude tend à inclure la totalité des pièces de ce site appartenant probablement au complexe châtelperronien. Elle comprend également les observations de nos propres fouilles, incluant un niveau châtelperronien en place. La série lithique de Germolles est placée dans le contexte du Châtelperronien en Bourgogne méridionale et dans l’Est de la France.The Grotte de la Verpillière I in Germolles (Saône-et-Loire, France) has yielded an archaeological sequence from the Middle Palaeolithic to the Gravettian period. This contribution focusses on the Châtelperronian lithic industry, covering 150 years of research. From a techno-typological point of view, all known lithic objects presumably dating to this period are subject of this investigation. This study includes in-situ observations of Châtelperronian layers, as part of our own recent excavations. The lithic assemblage is put into context with other Châtelperronian samples in Southern Burgundy and Eastern France
Association between antenatal glucocorticoid exposure and the activity of the stress system, cognition, and behavior in 8‐ to 9‐year‐old children: A prospective observational study
Introduction Glucocorticoid (GC) ‐induced fetal programming of the activity of the hypothalamus–pituitary–adrenal axis (HPAA) and its associated cognitive and behavioral consequences in later life have been well characterized in several animal species. However, information on humans is scarce. In this study, we examined HPAA activity markers and associated outcomes at 8 to 9 years of age among children prenatally exposed to GC for suspected preterm birth. Our hypothesis was that antenatal exposure to the betamethasone (BM) is associated with exacerbation of HPAA activity in childhood. Material and methods Prospective observational study in 31 children whose mothers received single ( n = 19) or multiple ( n = 12) courses of BM for threatened preterm birth but born with normal weight appropriate for the gestational age (median 37+ 6 weeks of gestation) compared with 38 non‐exposed, age‐matched children. Primary end point was the activity of the HPAA in response to the Trier Social Stress Test. Secondary end points were changes in autonomic nervous system (ANS) activity, cognitive performance (IQ), attention‐deficit/hyperactivity disorder (ADHD) symptoms, and electrocortical activity (EEG). Results There was no statistically significant difference in HPAA activity markers between antenatal BM exposed and unexposed groups. ANS activity in BM‐exposed children shifted towards a higher parasympathetic tone reflected by a higher overall high‐frequency band power of heart rate variability. IQ scores were within normal limits for both groups; however, BM‐exposed children had lower IQ scores than the unexposed group. BM‐exposed group had marginally more ADHD core symptoms and increased electrocortical activity in the occipital brain region compared with controls. A monotonic dose–response relation between BM exposure and activity of the ANS and IQ was estimated in post‐hoc analyses. Conclusions Antenatal exposure to BM in the context of threatened preterm birth was not associated with changes in HPAA activity in childhood. However, BM exposure may be associated with changes in ANS activity. Antenatal GC prophylaxis is a valuable and often life‐saving therapy, but its prescription may warrant a well‐balanced risk–benefit assessment
A new dynamical modeling of the WASP-47 system with CHEOPS observations
Among the hundreds of known hot Jupiters (HJs), only five have been found to have companions on short-period orbits. Within this rare class of multiple planetary systems, the architecture of WASP-47 is unique, hosting an HJ (planet-b) with both an inner and an outer sub-Neptunian mass companion (-e and -d, respectively) as well as an additional non-transiting, long-period giant (-c). The small period ratio between planets -b and -d boosts the transit time variation (TTV) signal, making it possible to reliably measure the masses of these planets in synergy with the radial velocity (RV) technique. In this paper, we present new space- and ground-based photometric data of WASP-47b and WASP-47-d, including 11 unpublished light curves from the ESA mission CHaracterising ExOPlanet Satellite (CHEOPS). We analyzed the light curves in a homogeneous way together with all the publicly available data to carry out a global N-body dynamical modeling of the TTV and RV signals. We retrieved, among other parameters, a mass and density for planet -d of Md = 15.5 ± 0.8 M⊕ and ρd = 1.69 ± 0.22 g cm−3, which is in good agreement with the literature and consistent with a Neptune-like composition. For the inner planet (-e), we found a mass and density of Me = 9.0 ± 0.5 M⊕ and ρe = 8.1 ± 0.5 g cm−3, suggesting an Earth-like composition close to other ultra-hot planets at similar irradiation levels. Though this result is in agreement with previous RV plus TTV studies, it is not in agreement with the most recent RV analysis (at 2.8σ), which yielded a lower density compatible with a pure silicate composition. This discrepancy highlights the still unresolved issue of suspected systematic offsets between RV and TTV measurements. In this paper, we also significantly improve the orbital ephemerides of all transiting planets, which will be crucial for any future follow-up
A full transit of v2 Lupi d and the search for an exomoon in its Hill sphere with CHEOPS
The planetary system around the naked-eye star v2 Lupi (HD 136352; TOI-2011) is composed of three exoplanets with masses of 4.7, 11.2, and 8.6 Earth masses (M⊕). The TESS and CHEOPS missions revealed that all three planets are transiting and have radii straddling the radius gap separating volatile-rich and volatile-poor super-earths. Only a partial transit of planet d had been covered so we re-observed an inferior conjunction of the long-period 8.6 M⊕ exoplanet v2 Lup d with the CHEOPS space telescope. We confirmed its transiting nature by covering its whole 9.1 h transit for the first time. We refined the planet transit ephemeris to P = 107.1361−0.0022+0.0019 days and Tc = 2459009.7759−0.0096+0.0101 BJDTDB, improving by ~40 times on the previously reported transit timing uncertainty. This refined ephemeris will enable further follow-up of this outstanding long-period transiting planet to search for atmospheric signatures or explore the planet’s Hill sphere in search for an exomoon. In fact, the CHEOPS observations also cover the transit of a large fraction of the planet’s Hill sphere, which is as large as the Earth’s, opening the tantalising possibility of catching transiting exomoons. We conducted a search for exomoon signals in this single-epoch light curve but found no conclusive photometric signature of additional transiting bodies larger than Mars. Yet, only a sustained follow-up of v2 Lup d transits will warrant a comprehensive search for a moon around this outstanding exoplanet
Characterization of the HD 108236 system with CHEOPS and TESS Confirmation of a fifth transiting planet
Context. The HD 108236 system was first announced with the detection of four small planets based on TESS data. Shortly after, the transit of an additional planet with a period of 29.54 d was serendipitously detected by CHEOPS. In this way, HD 108236 (V = 9.2) became one of the brightest stars known to host five small transiting planets (Rp < 3 R⊕).
Aims. We characterize the planetary system by using all the data available from CHEOPS and TESS space missions. We use the flexible pointing capabilities of CHEOPS to follow up the transits of all the planets in the system, including the fifth transiting body.
Methods. After updating the host star parameters by using the results from Gaia eDR3, we analyzed 16 and 43 transits observed by CHEOPS and TESS, respectively, to derive the planets’ physical and orbital parameters. We carried out a timing analysis of the transits of each of the planets of HD 108236 to search for the presence of transit timing variations.
Results. We derived improved values for the radius and mass of the host star (R★ = 0.876 ± 0.007 R0 and M★ = 0.867-0.046+0.047M⊙). We confirm the presence of the fifth transiting planet f in a 29.54 d orbit. Thus, the HD 108236 system consists of five planets of Rb = 1.587±0.028, Rc = 2.122±0.025, Rd = 2.629 ± 0.031, Re = 3.008 ± 0.032, and Rf = 1.89 ± 0.04 [R⊕]. We refine the transit ephemeris for each planet and find no significant transit timing variations for planets c, d, and e. For planets b and f, instead, we measure significant deviations on their transit times (up to 22 and 28 min, respectively) with a non-negligible dispersion of 9.6 and 12.6 min in their time residuals.
Conclusions. We confirm the presence of planet f and find no significant evidence for a potential transiting planet in a 10.9 d orbital period, as previously suggested. Further monitoring of the transits, particularly for planets b and f, would confirm the presence of the observed transit time variations. HD 108236 thus becomes a key multi-planetary system for the study of formation and evolution processes. The reported precise results on the planetary radii – together with a profuse RV monitoring – will allow for an accurate characterization of the internal structure of these planets
55 Cancri e’s occultation captured with CHEOPS
Past occultation and phase-curve observations of the ultra-short period super-Earth 55 Cnc e obtained at visible and infrared wavelengths have been challenging to reconcile with a planetary reflection and emission model. In this study, we analyse a set of 41 occultations obtained over a two-year timespan with the CHEOPS satellite. We report the detection of 55 Cnc e’s occultation with an average depth of 12 ± 3 ppm. We derive a corresponding 2σ upper limit on the geometric albedo of Ag < 0.55 once decontaminated from the thermal emission measured by Spitzer at 4.5 µm. CHEOPS’s photometric performance enables, for the first time, the detection of individual occultations of this super-Earth in the visible and identifies short-timescale photometric corrugations likely induced by stellar granulation. We also find a clear 47.3-day sinusoidal pattern in the time-dependent occultation depths that we are unable to relate to stellar noise, nor instrumental systematics, but whose planetary origin could be tested with upcoming JWST occultation observations of this iconic super-Earth
The HD 93963 A transiting system: A 1.04 d super-Earth and a 3.65 d sub-Neptune discovered by TESS and CHEOPS
We present the discovery of two small planets transiting HD 93963A (TOI-1797), a GOV star (M* = 1.109 ± 0.043M⊙, R* = 1.043 ± 0.009 R⊙) in a visual binary system. We combined TESS and CHEOPS space-borne photometry with MuSCAT 2 ground-based photometry, ‘Alopeke and PHARO high-resolution imaging, TRES and FIES reconnaissance spectroscopy, and SOPHIE radial velocity measurements. We validated and spectroscopically confirmed the outer transiting planet HD 93963 A c, a sub-Neptune with an orbital period of Pc ≈ 3.65 d that was reported to be a TESS object of interest (TOI) shortly after the release of Sector 22 data. HD 93963 A c has amass of Mc = 19.2 ± 4.1 M⊕ and a radius of Rc = 3.228 ± 0.059 R⊕, implying a mean density of ρc = 3.1 ± 0.7 g cm-3. The inner object, HD 93963 A b, is a validated 1.04 d ultra-short period (USP) transiting super-Earth that we discovered in the TESS light curve and that was not listed as a TOI, owing to the low significance of its signal (TESS signal-to-noise ratio ≈6.7, TESS + CHEOPS combined transit depth Db = 141.5−8.3+8.5 ppm). We intensively monitored the star with CHEOPS by performing nine transit observations to confirm the presence of the inner planet and validate the system. HD 93963 A b is the first small (Rb = 1.35 ± 0.042 R⊕) USP planet discovered and validated by TESS and CHEOPS. Unlike planet c, HD 93963 Ab is not significantly detected in our radial velocities (Mb = 7.8 ± 3.2 M⊕). The two planets are on either side of the radius valley, implying that they could have undergone completely different evolution processes. We also discovered a linear trend in our Doppler measurements, suggesting the possible presence of a long-period outer planet. With a V-band magnitude of 9.2, HD 93963 A is among the brightest stars known to host a USP planet, making it one of the most favourable targets for precise mass measurement via Doppler spectroscopy and an important laboratory to test formation, evolution, and migration models of planetary systems hosting ultra-short period planets
The stable climate of KELT-9b
Even among the most irradiated gas giants, so-called ultra-hot Jupiters, KELT-9b stands out as the hottest planet thus far discovered with a dayside temperature of over 4500 K. At these extreme irradiation levels, we expect an increase in heat redistribution efficiency and a low Bond albedo owed to an extended atmosphere with molecular hydrogen dissociation occurring on the planetary dayside. We present new photometric observations of the KELT-9 system throughout 4 full orbits and 9 separate occultations obtained by the 30 cm space telescope CHEOPS. The CHEOPS bandpass, located at optical wavelengths, captures the peak of the thermal emission spectrum of KELT-9b. In this work we simultaneously analyse CHEOPS phase curves along with public phase curves from TESS and Spitzer to infer joint constraints on the phase curve variation, gravity-darkened transits, and occultation depth in three bandpasses, as well as derive 2D temperature maps of the atmosphere at three different depths. We find a day-night heat redistribution efficiency of ~0.3 which confirms expectations of enhanced energy transfer to the planetary nightside due to dissociation and recombination of molecular hydrogen. We also calculate a Bond albedo consistent with zero. We find no evidence of variability of the brightness temperature of the planet, excluding variability greater than 1
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