Signs of strong Na and K absorption in the transmission spectrum of WASP-103b

Context: Transmission spectroscopy has become a prominent tool for characterizing the atmospheric properties on close-in transiting planets. Recent observations have revealed a remarkable diversity in exoplanet spectra, which show absorption signatures of Na, K and $\mathrm{H_2O}$, in some cases partially or fully attenuated by atmospheric aerosols. Aerosols (clouds and hazes) themselves have been detected in the transmission spectra of several planets thanks to wavelength-dependent slopes caused by the particles' scattering properties. Aims: We present an optical 550 - 960 nm transmission spectrum of the extremely irradiated hot Jupiter WASP-103b, one of the hottest (2500 K) and most massive (1.5 $M_J$) planets yet to be studied with this technique. WASP-103b orbits its star at a separation of less than 1.2 times the Roche limit and is predicted to be strongly tidally distorted. Methods: We have used Gemini/GMOS to obtain multi-object spectroscopy hroughout three transits of WASP-103b. We used relative spectrophotometry and bin sizes between 20 and 2 nm to infer the planet's transmission spectrum. Results: We find that WASP-103b shows increased absorption in the cores of the alkali (Na, K) line features. We do not confirm the presence of any strong scattering slope as previously suggested, pointing towards a clear atmosphere for the highly irradiated, massive exoplanet WASP-103b. We constrain the upper boundary of any potential cloud deck to reside at pressure levels above 0.01 bar. This finding is in line with previous studies on cloud occurrence on exoplanets which find that clouds dominate the transmission spectra of cool, low surface gravity planets while hot, high surface gravity planets are either cloud-free, or possess clouds located below the altitudes probed by transmission spectra.Comment: Accepted for publication in A&

PyTranSpot\texttt{PyTranSpot} - A tool for multiband light curve modeling of planetary transits and stellar spots

Several studies have shown that stellar activity features, such as occulted and non-occulted starspots, can affect the measurement of transit parameters biasing studies of transit timing variations and transmission spectra. We present $\texttt{PyTranSpot}$, which we designed to model multiband transit light curves showing starspot anomalies, inferring both transit and spot parameters. The code follows a pixellation approach to model the star with its corresponding limb darkening, spots, and transiting planet on a two dimensional Cartesian coordinate grid. We combine $\texttt{PyTranSpot}$ with an MCMC framework to study and derive exoplanet transmission spectra, which provides statistically robust values for the physical properties and uncertainties of a transiting star-planet system. We validate $\texttt{PyTranSpot}$'s performance by analyzing eleven synthetic light curves of four different star-planet systems and 20 transit light curves of the well-studied WASP-41b system. We also investigate the impact of starspots on transit parameters and derive wavelength dependent transit depth values for WASP-41b covering a range of 6200-9200 $\AA$, indicating a flat transmission spectrum.Comment: 17 pages, 22 figures; accepted for publication in Astronomy & Astrophysic

Karakteristik Petani Padi Peserta Program Upaya Khusus Padi Jagung Kedelai (Upsus Pajale)di Desa Bunga Raya Kecamatan Bunga Raya Kabupaten Siak

This research is intended to understand the characteristic of the farmers, stage on the Specially Efforts Corn, Soybean, Paddy(UPSUS PAJALE) at Bunga Raya village. This research was conducted at Bunga Raya village that is located in the Siak Regency. Multi stage sampling was used as the method to choose locations. The samples were gathered using Purposive Sampling method. This research uses 48 farmers data as samples. Data analysis which is used for this research is the descriptive method. The goals were analyzed using Likert Scale. The results of this research shows us the paddy farmers' internal characteristics at Bunga Raya village such as: the farmers' productive ages are within the range of 40-46 years, most of the farmers' are High School graduates, each farmers' family consists of 4-5 persons, farmers' experiences are between 17-23 years, the land area that the farmers manage is between 0,5-1ha and the farmers are highly cosmopolitans. The external characteristics of farmers are medium when are evaluated according to the instructors' intensity, the accuracy of instructors channel, the amount of information sources, the affordability of production facilities price and the availability of production facilities

Some colouring problems for Paley graphs

The Paley graph Pq, where q≡1(mod4) is a prime power, is the graph with vertices the elements of the finite field Fq and an edge between x and y if and only if x-y is a non-zero square in Fq. This paper gives new results on some colouring problems for Paley graphs and related discussion. © 2005 Elsevier B.V. All rights reserved

GJ1214: Rotation period, starspots, and uncertainty on the optical slope of the transmission spectrum

Brightness inhomogeneities in the stellar photosphere (dark spots or bright regions) affect the measurements of the planetary transmission spectrum. To investigate the star spots of the M dwarf GJ 1214, we conducted a multicolor photometric monitoring from 2012 to 2016. The measured variability shows a periodicity of 125 +- 5 days, which we interpret as the signature of the stellar rotation period. This value overrules previous suggestions of a significantly shorter stellar rotation period. A light curve inversion of the monitoring data yields an estimation of the flux dimming of a permanent spot filling factor not contributing to the photometric variability, a temperature contrast of the spots of about 370 K and persistent active longitudes. The derived surface maps over all five seasons were used to estimate the influence of the star spots on the transmission spectrum of the planet from 400 nm to 2000 nm. The monitoring data presented here do not support a recent interpretation of a measured transmission spectrum of GJ 1214b as to be caused by bright regions in the stellar photosphere. Instead, we list arguments as to why the effect of dark spots likely dominated over bright regions in the period of our monitoring. Furthermore, our photometry proves an increase in variability over at least four years, indicative for a cyclic activity behavior. The age of GJ 1214 is likely between 6 and 10 Gyr. The long-term photometry allows for a correction of unocculted spots. For an active star such as GJ 1214, there remains a degeneracy between occulted spots and the transit parameters used to build the transmission spectrum. This degeneracy can only be broken by high-precision transit photometry resolving the spot crossing signature in the transit light curve.Comment: 11 pages, 8 figures, accepted for publication in Astronomy & Astrophysic

Irreducible triangulations of surfaces with boundary

A triangulation of a surface is irreducible if no edge can be contracted to produce a triangulation of the same surface. In this paper, we investigate irreducible triangulations of surfaces with boundary. We prove that the number of vertices of an irreducible triangulation of a (possibly non-orientable) surface of genus g>=0 with b>=0 boundaries is O(g+b). So far, the result was known only for surfaces without boundary (b=0). While our technique yields a worse constant in the O(.) notation, the present proof is elementary, and simpler than the previous ones in the case of surfaces without boundary

Physical properties and transmission spectrum of the WASP-74 planetary system from multi-band photometry

We present broad-band photometry of eleven planetary transits of the hot Jupiter WASP-74 b, using three medium-class telescopes and employing the telescope-defocussing technique. Most of the transits were monitored through I filters and one was simultaneously observed in five optical (U,g′,r′,i′,z′) and three near infrared (J, H, K) passbands, for a total of 18 light curves. We also obtained new high-resolution spectra of the host star. We used these new data to review the orbital and physical properties of the WASP-74 planetary system. We were able to better constrain the main system characteristics, measuring smaller radius and mass for both the hot Jupiter and its host star than previously reported in the literature. Joining our optical data with those taken with the HST in the near infrared, we built up an observational transmission spectrum of the planet, which suggests the presence of strong optical absorbers, as TiO and VO gases, in its atmosphere

Far-UV spectroscopy of the planet-hosting star WASP-13: High-energy irradiance, distance, age, planetary mass-loss rate, and circumstellar environment

Several transiting hot Jupiters orbit relatively inactive main-sequence stars. For some of those, the {log}{R}{HK}\prime activity parameter lies below the basal level (-5.1). Two explanations have been proposed so far: (i) the planet affects the stellar dynamo, (ii) the {log}{R}{HK}\prime measurements are biased by extrinsic absorption, either by the interstellar medium (ISM) or by material local to the system. We present here Hubble Space Telescope/COS far-UV spectra of WASP-13, which hosts an inflated hot Jupiter and has a measured {log}{R}{HK}\prime value (-5.26), well below the basal level. From the star's spectral energy distribution we obtain an extinction E(B - V) = 0.045 ± 0.025 mag and a distance d = 232 ± 8 pc. We detect at ≳4σ lines belonging to three different ionization states of carbon (C i, C ii, and C iv) and the Si iv doublet at ˜3σ. Using far-UV spectra of nearby early G-type stars of known age, we derive a C iv/C i flux ratio-age relation, from which we estimate WASP-13's age to be 5.1 ± 2.0 Gyr. We rescale the solar irradiance reference spectrum to match the flux of the C iv 1548 doublet. By integrating the rescaled solar spectrum, we obtain an XUV flux at 1 AU of 5.4 erg s-1 cm-2. We use a detailed model of the planet's upper atmosphere, deriving a mass-loss rate of 1.5 × 1011 g s-1. Despite the low {log}{R}{HK}\prime value, the star shows a far-UV spectrum typical of middle-aged solar-type stars, pointing toward the presence of significant extrinsic absorption. The analysis of a high-resolution spectrum of the Ca ii H&K lines indicates that the ISM absorption could be the origin of the low {log}{R}{HK}\prime value. Nevertheless, the large uncertainty in the Ca ii ISM abundance does not allow us to firmly exclude the presence of circumstellar gas. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from MAST at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program #13859

Fluorescence‐based bowel anastomosis perfusion evaluation: results from the IHU‐IRCAD‐EAES EURO‐FIGS registry

Background: Anastomotic leakage (AL) is one of the dreaded complications following surgery in the digestive tract. Near-infrared fluorescence (NIRF) imaging is a means to intraoperatively visualize anastomotic perfusion, facilitating fluorescence image-guided surgery (FIGS) with the purpose to reduce the incidence of AL. The aim of this study was to analyze the current practices and results of NIRF imaging of the anastomosis in digestive tract surgery through the EURO-FIGS registry. Methods: Analysis of data prospectively collected by the registry members provided patient and procedural data along with the ICG dose, timing, and consequences of NIRF imaging. Among the included upper-GI, colorectal, and bariatric surgeries, subgroup analysis was performed to identify risk factors associated with complications. Results: A total of 1240 patients were included in the study. The included patients, 74.8% of whom were operated on for cancer, originated from 8 European countries and 30 hospitals. A total of 54 surgeons performed the procedures. In 83.8% of cases, a pre-anastomotic ICG dose was administered, and in 60.1% of cases, a post-anastomotic ICG dose was administered. A significant difference (p < 0.001) was found in the ICG dose given in the four pathology groups registered (range: 0.013–0.89 mg/kg) and a significant (p < 0.001) negative correlation was found between the ICG dose and BMI. In 27.3% of the procedures, the choice of the anastomotic level was guided by means of NIRF imaging which means that in these cases NIRF imaging changed the level of anastomosis which was first decided based on visual findings in conventional white light imaging. In 98.7% of the procedures, the use of ICG partly or strongly provided a sense of confidence about the anastomosis. A total of 133 complications occurred, without any statistical significance in the incidence of complications in the anastomoses, whether they were ICG-guided or not. Conclusion: The EURO-FIGS registry provides an insight into the current clinical practice across Europe with respect to NIRF imaging of anastomotic perfusion during digestive tract surgery