Achieving maximum scientific results from the overwhelming volume of astronomical data to be acquired over the next few decades demands novel, fully automatic methods of data analysis. Here we ...concentrate on eclipsing binary (EB) stars, a prime source of astrophysical information, of which only some hundreds have been rigorously analyzed, but whose numbers will reach millions in a decade. We describe the artificial neural network (ANN) approach which is able to surmount the human bottleneck and permit EB-based scientific yield to keep pace with future data rates. The ANN, following training on a sample of 33,235 model light curves, outputs a set of approximate model parameters image, and image for each input light curve data set. The obtained parameters can then be readily passed to sophisticated modeling engines. We also describe a novel method polyfit for preprocessing observational light curves before inputting their data to the ANN and present the results and analysis of testing the approach on synthetic data and on real data including 50 binaries from the Catalog and Atlas of Eclipsing Binaries (CALEB) database and 2580 light curves from OGLE survey data. The success rate, defined by less than a 10% error in the network output parameter values, is approximately 90% for the OGLE sample and close to 100% for the CALEB sample-sufficient for a reliable statistical analysis. The code is made available to the public. Our approach is applicable to EB light curves of all classes; this first paper in the eclipsing binaries via artificial intelligence (EBAI) series focuses on detached EBs, which is the class most challenging for this approach.
We present the results of our analysis on V1481 Ori (JW 239), a young SB2 in the Orion nebula Cluster with a circumbinary disc accreting on the lower mass component. The analysis is based on ...high-resolution spectroscopic data and high-quality photometric time series about 20-yr long. Thanks to the spectroscopy, we confirm the binary nature of this system consisting of M3 + M4 components and derive the mass ratio M
B/M
A = 0.54, a variable luminosity ratio L
B/L
A = 0.68–0.94, and an orbital period P
orb = 4.433 d. The photometric data allowed us to measure the rotation periods of the two components P
phot = 4.4351 d and they are found to be synchronized with the orbital period. The simultaneous modelling of V-, I-band, and radial velocity curves in the 2005 season suggests that the variability is dominated by one hotspot on the secondary component covering at least ∼3.5 per cent of the stellar surface and about 420 K hotter than the unperturbed photosphere. Such a spot may originate from the material of the circumbinary disc accreting on to the secondary component. We also detect an apparent 6-yr periodic variation in the position of this hotspot, which is inferred from the phase migration of the light-curve maximum, which we interpret as due to either the presence of surface differential rotation as large as 0.065 per cent, a value compatible with the fully convective components, or to a periodic exchange of angular momentum between the disc and the star, which implies a minimum magnetic field strength of 650 G at the stellar surface.
Aprepitant is a highly selective substance P (neurokinin 1 NK
1 receptor) antagonist that significantly improves the pharmacotherapy of acute and delayed highly emetogenic chemotherapy–induced nausea ...and vomiting, probably through an action in the brain stem region of the central nervous system. Here, we report the use of positron emission tomography imaging with the NK
1 receptor binding–selective tracer
18FSPA-RQC to determine the levels of central NK
1 receptor occupancy achieved by therapeutically relevant doses of aprepitant in healthy humans.
Two single-blind, randomized, placebo-controlled studies in healthy subjects were performed. The first study evaluated the plasma concentration–occupancy relationships for aprepitant dosed orally at 10, 30, 100, or 300 mg, or placebo (
n = 12). The second study similarly evaluated oral aprepitant 30 mg and placebo (
n = 4). In each study, dosing was once daily for 14 consecutive days. Data from both studies were combined for analyses. The ratio of striatal/cerebellar
18FSPA-RQ (high receptor density region/reference region lacking receptors) was used to calculate trough receptor occupancy 24 hours after the last dose of aprepitant.
Brain NK
1 receptor occupancy increased after oral aprepitant dosing in both a plasma concentration–related (
r = .97; 95% confidence interval CI = .94–1.00,
p < .001) and a dose-related (
r = .94; 95% CI = .86–1.00,
p < .001) fashion. High (≥90%) receptor occupancy was achieved at doses of 100 mg/day or greater. The plasma concentrations of aprepitant that achieved 50% and 90% occupancy were estimated as approximately 10 ng/mL and approximately 100 ng/mL, respectively.
Positron emission tomography imaging with
18FSPA-RQ allows brain NK
1 receptor occupancy by aprepitant to be predicted from plasma drug concentrations and can be used to guide dose selection for clinical trials of NK
1 receptor antagonists in central therapeutic indications.
•We present the analysis of spectroscopic and new photometric observations of HH Boo.•The period changes in the observed − calculated (O − C) diagram were analyzed.•The “Half-Period” variation is ...defined and analyzed.•The orbital and physical parameters of the system were derived.•Our model describes HH Bootis as a W-type overcontact binary in contrast to previous workers.
We present the results of our investigation on the geometrical and physical parameters of the W UMa type binary system HH Bootis from new CCD (BVRI) light curves and published radial velocity data. The photometric data were obtained in 2011 and 2012 at Ankara University Observatory (AUO). Light and radial velocity observations were analyzed simultaneously using the Wilson–Devinney (2013 revision) code to obtain absolute and geometrical parameters. The system was determined to be a W-type W UMa system of a type different from that suggested by Dal and Sipahi (2013). An interesting cyclic period variation in the time intervals between primary and secondary eclipses (“half-period variation”) was discovered and analyzed and its possible cause is discussed. Combining our photometric solution with the spectroscopic data we derived masses and radii of the eclipsing system to be M1=0.627M⊙,M2=1.068M⊙,R1=0.782R⊙ and R2=0.997R⊙. New light elements were derived and finally the evolutionary status of the system is discussed.
•We present the analysis of spectroscopic and photometric observations of BO Arietis.•Complete light curves were observed and new times of minima were calculated.•The period changes in ...Observed–Calculated (O–C) diagram were analyzed.•The orbital and physical parameters of the system were obtained.•Our model describes BO Ari as an A-type overcontact system.
We present the results of our investigation on the geometrical and physical parameters of the W UMa type binary system BO Ari from analyzed CCD (BVRI) light curves and radial velocity data. The photometric data were obtained in 2009 and 2010 at Ankara University Observatory (AUO) and the spectroscopic observations were made in 2007 and 2010 at TUBITAK National Observatory (TUG). These light and radial velocity observations were analyzed simultaneously by using the Wilson–Devinney (2013 revision) code to obtain absolute and geometrical parameters. The system was determined to be an A-type W UMa system. Combining our photometric solution with the spectroscopic data we derived masses and radii of the eclipsing system to be M1=0.995M⊙,M2=0.189M⊙,R1=1.090R⊙ and R2=0.515R⊙. Finally, we discuss the evolutionary status of the system.
This work presents the first large-scale photometric variability survey of the intermediate-age (~200 Myr) open cluster M11. Thirteen nights of data over two observing seasons were analyzed (using ...crowded field and ensemble photometry techniques) to obtain high relative precision photometry. In this study we focus on the detection of candidate member variable stars for follow-up studies. A total of 39 variable stars were detected and can be categorized as follows: one irregular (probably pulsating) variable, six d Scuti variables, 14 detached eclipsing binary systems, 17 W UMa variables, and one unidentified/candidate variable. While previous proper-motion studies allow for cluster membership determination for the brightest stars, we find that membership determination is significantly hampered below V = 15, R = 15.5 by the large population of field stars overlapping the cluster main sequence. Of the brightest detected variables that have a high likelihood of cluster membership, we find five systems in which further work could help constrain theoretical stellar models, including one potential W UMa member of this young cluster.
Detached eclipsing binaries (EBs) provide a unique opportunity to carry out stringent tests on stellar evolution models. The value of EBs is enhanced by their membership in open clusters, but the ...number of known systems is still very scarce. We have started a systematic search for late-type EBs in the nearest open clusters with the fully robotic ROTSE3b telescope at McDonald Observatory in West Texas. On our first campaigns on the Hyades and Collinder 359, we have identified a number of previously unknown eclipsing binary candidates. Some of these stars have been selected for spectroscopic and photometric follow-up. Here we present details of the observing and reduction strategy as well as the first results of this ongoing survey.
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