scholarly journals New MOST Photometry of the 55 Cancri System

2012 ◽  
Vol 8 (S293) ◽  
pp. 52-57 ◽  
Author(s):  
Diana Dragomir ◽  
Jaymie M. Matthews ◽  
Joshua N. Winn ◽  
Jason F. Rowe ◽  
Keyword(s):  
Orbital Period ◽  
Phase Variation ◽  
Cnc System ◽  
Data Set ◽  
Upper Limit ◽  
Nearly Continuous ◽  
Geometric Albedo

AbstractSince the discovery of its transiting nature, the super-Earth 55 Cnc e has become one of the most enthusiastically studied exoplanets, having been observed spectroscopically and photometrically, in the ultraviolet, optical and infrared regimes. To this rapidly growing data set, we contribute 42 days of new, nearly continuous MOST photometry of the 55 Cnc system. Our analysis of these observations together with the discovery photometry obtained in 2011 allows us to determine the planetary radius (1.990+0.084−0.080) and orbital period (0.7365417+0.0000025−0.0000028) of 55 Cnc e with unprecedented precision. We also followed up on the out-of-transit phase variation first observed in the 2011 photometry, and set an upper limit on the depth of the planet's secondary eclipse, leading to an upper limit on its geometric albedo of 0.6.

scholarly journals MOST Spacebased Photometry of HD 189733: Precise Timing Measurements for Transits Across an Active Star

2008 ◽  
Vol 4 (S253) ◽  
pp. 459-461
Author(s):  
E. Miller-Ricci ◽  
J. F. Rowe ◽  
D. Sasselov ◽  
J. M. Matthews ◽  
R. Kuschnig ◽  
...  
Keyword(s):  
Orbital Period ◽  
Mass Range ◽  
Active Star ◽  
Precise Timing ◽  
Resonant Orbits ◽  
The Earth ◽  
Test Spot ◽  
Transit Times ◽  
Nearly Continuous ◽  
Parent Star

AbstractWe have measured transit times for HD 189733 passing in front of its bright (V = 7.67) chromospherically active and spotted parent star. Nearly continuous broadband photometry of this system was obtained with the MOST (Microvariability & Oscillations of STars) space telesope during 21 days in August 2006, monitoring 10 consecutive transits. We have used these data to search for deviations from a constant orbital period which can indicate the presence of additional planets in the system that are as yet undetected by Doppler searches. We find no variations above the level of ±45 s, ruling out planets in the Earth-to-Neptune mass range in a number of resonant orbits. We find that a number of complications can arise in measuring transit times for a planet transiting an active star with large star spots. However, such transiting systems are also useful in that they can help to constrain and test spot models. This has implications for the large number of transiting systems expected to be discovered by the CoRoT and Kepler missions.

scholarly journals IR Geminorum: Complex Disk Behavior During Quiescence

2004 ◽  
Vol 191 ◽  
pp. 259-262
Author(s):  
Zongyun Li ◽  
Kam-Ching Leung ◽  
C. Martin Gaskell
Keyword(s):  
Orbital Period ◽  
V Band ◽  
Eccentric Disk ◽  
Nearly Continuous ◽  
Periodic Cycles

AbstractWe have carried out nearly continuous V-band photometry from Yunnan Observatory (China) and Behlen Observatory (Nebraska, USA) of IR Gem for over six days starting three days after a normal outburst in January 2002. Our observations show that the behavior of this SU UMa star is unexpectedly complicated, and that for IR Gem, quiescence is potentially more interesting than outbursts. We find a photometric modulation with a period of 98.5 min, exactly equal to the spectroscopically determined orbital period. We tentatively attribute this to heating of the secondary. During the first three days a modulation appeared with a period 5% longer than the orbital period. We suggest that this might be a signature of apsidal precession of an eccentric disk. During the middle of our period of observations a modulation with a period 3% shorter than the orbital period appeared. We invoke nodal precession to explain this. A slower modulation we found with a period of about 1.7 d is roughly consistent with the expected period of nodal precession. There is a puzzling 4.3 d period modulation that we suspect may be the result of beating between apsidal and nodal precession frequencies. We also find inexplicable quasi-periodic cycles on timescales drifting from ~ 0.2 to ~ 0.4 days.

Superhump period of SDSS J214354.59+124457.8: First Z Cam star with superhumps in the standstill

2019 ◽  
Vol 489 (1) ◽  
pp. 1451-1462
Author(s):  
Metin Altan ◽  
Taichi Kato ◽  
Ryoko Ishioka ◽  
Linda Schmidtobreick ◽  
Tolga Güver ◽  
...  
Keyword(s):  
Light Curve ◽  
Orbital Period ◽  
Timing Analysis ◽  
Periodic Signal ◽  
Mass Ratio ◽  
Short Intervals ◽  
Upper Limit ◽  
Term Variation ◽  
Two Phases

Abstract The cataclysmic variable SDSS J214354.59+124457.8 (hereafter SDSS J214354) was observed photometrically on sixty one nights between 2012 July 28 and 2019 May 26. The long term variation of this object shows changes between two phases; a dwarf nova type and a novalike. This implies that the object belongs to the group of Z Cam type stars. The timing analysis of the light curve reveals a periodic signal at 0.13902(5) d, which we identify as the superhump period. However, the fractional superhump excess of 10 per cent longer than the orbital period is exceptionally large. We obtained a mass ratio of ∼0.4, which is above the accepted upper limit of q = 0.33 for the formation of superhumps. We suggest that the object contains a secondary with an evolved core. With an orbital period of 0.126 d, SDSS J214354 is situated at the upper border of the period gap. The long term light curve of SDSS J214354 is similar to those of Z Cam type stars which are characterized by recurring standstills, followed by short intervals with DN type outbursts. Therefore, we conclude that SDSS J214354 is a new member of the Z Cam type stars.

How loan interest rate liberalization affects firms’ loan maturity structure

2014 ◽  
Vol 4 (2) ◽  
pp. 153-167 ◽  
Author(s):  
Jianfang Zhou ◽  
Jingjing Wang ◽  
Jianping Ding
Keyword(s):  
Interest Rate ◽  
Interest Rates ◽  
Manufacturing Companies ◽  
Short Term ◽  
Data Set ◽  
Content Type ◽  
Interest Rate Liberalization ◽  
Upper Limit ◽  
Maturity Structure

Purpose – After loan interest rate upper limit deregulation in October 2004, the financing environment in China changed dramatically, and the banks were eligible for risk compensation. The purpose of this paper is to focus on the influence of the loan interest rate liberalization on firms’ loan maturity structure. Design/methodology/approach – Based on Rajan's (1992) model, the authors constructed a trade-off model of how the banks choose long-term and short-term loans scales, and further analyzed banks’ loan term decisions under the loan interest rate upper limit deregulation or collateral cases. Then the authors used an unbalanced panel data set of 586 Chinese listed manufacturing companies and 9,376 observations during the period 1996-2011 to testify the theoretical conclusion. Furthermore, the authors studied the effect on firms with different characteristics of ownership or scale. Findings – The results show that the loan interest rate liberalization significantly decreases the private companies’ reliance on short-term loans and increases sensitivity to interest rates of state-owned companies’ long-term loans. But the results also show that the companies’ ownership still plays a key role on the long-term loans availability. When monetary policy tightened, small companies still have to borrow short-term loans for long-term purposes. As the bank industry is still dominated by state-owned banks and the deposit interest rate has upper limits, the effect of the loan interest rate liberalization on easing long-term credit constraints is limited. Originality/value – From a new perspective, the content and findings of this paper contribute to the study of the effect of the interest rate liberalization on China economy.

On the use of dispersive APVO GPR curves for thin-bed properties estimation: Theory and application to fracture characterization

Geophysics ◽  
2009 ◽  
Vol 74 (1) ◽  
pp. J1-J12 ◽  
Author(s):  
Jacques Deparis ◽  
Stéphane Garambois
Keyword(s):  
Ground Penetrating Radar ◽  
Inverse Method ◽  
Phase Variation ◽  
Fractured Media ◽  
Data Set ◽  
Fracture Characterization ◽  
Propagation Effects ◽  
Phase Liquid ◽  
Ground Penetrating ◽  
Homogeneous Formation

The presence of a thin layer embedded in any formation creates complex reflection patterns caused by interferences within the thin bed. The generated reflectivity amplitude variations with offset have been increasingly used in seismic interpretation and more recently tested on ground-penetrating radar (GPR) data to characterize nonaqueous-phase liquid contaminants. Phase and frequency sensitivities of the reflected signals are generally not used, although they contain useful information. The present study aims to evaluate the potential of these combined properties to characterize a thin bed using GPR data acquired along a common-midpoint (CMP) survey, carried out to assess velocity variations in the ground. It has been restricted to the simple case of a thin bed embedded within a homogeneous formation, a situation often encountered in fractured media. Dispersive properties ofthe dielectric permittivity of investigated materials (homogeneous formation, thin bed) are described using a Jonscher parameterization, which permitted study of the dependency of amplitude and phase variation with offset (APVO) curves on frequency and thin-bed properties (filling nature, aperture). In the second part, we discuss and illustrate the validity of the thin-bed approximation as well as simplify assumptions and make necessary careful corrections to convert raw CMP data into dispersive APVO curves. Two different strategies are discussed to correct the data from propagation effects: a classical normal-moveout approach and an inverse method. Finally, the proposed methodology is applied to a CMP GPR data set acquired along a vertical cliff. It allowed us to extract the characteristics of a subvertical fracture with satisfying resolution and confidence. The study motivates interest to use dispersion dependency of the reflection coefficient variations for thin-bed characterization.

scholarly journals Latest Belle results on Tau decays

2019 ◽  
Author(s):  
Yifan Jin ◽  
Denis Epifanov ◽  
Hiroaki Aihara
Keyword(s):  
Confidence Level ◽  
Branching Fraction ◽  
Data Set ◽  
Tau Decays ◽  
Preliminary Results ◽  
Upper Limit

We present preliminary results of a latest measurement at Belle, the branching fraction of rare tau decay, \tau^- \rightarrow \pi^- \nu_{\tau} \ell^+ \ell^-τ−→π−ντℓ+ℓ− (\ell = eℓ=e or \muμ), using a 562 \rm fb^{-1} data set. The branching fraction of \tau^- \rightarrow \pi^- e^+ e^- \nu_\tauτ−→π−e+e−ντ is measured to be \mathbf{ \mathcal{B}(\tau^-\rightarrow \pi^- e^+ e^- \nu_\tau) = (2.11 \pm 0.19 \pm 0.30) \times 10^{-5}}ℬ(𝛕−→𝛑−𝐞+𝐞−𝛎𝛕)=(2.11±0.19±0.30)×10−5, where the first uncertainty is statistical and the second is systematic. An upper limit is set on the branching fraction of \tau^- \rightarrow \pi^- \mu^+ \mu^- \nu_\tauτ−→π−μ+μ−ντ, \mathbf{\mathcal{B}(\tau^-\rightarrow \pi^- \mu^+ \mu^- \nu_\tau) < 1.06 \times 10^{-5}}ℬ(𝛕−→𝛑−𝛍+𝛍−𝛎𝛕)<1.06×10−5, at 90% confidence level.

scholarly journals Characterising phase variations in MALDI-TOF data and correcting them by peak alignment

2005 ◽  
Vol 1 ◽  
pp. 117693510500100 ◽  
Author(s):  
Simon M Lin ◽  
Richard P Haney ◽  
Michael J Campa ◽  
Michael C Fitzgerald ◽  
Edward F Patz
Keyword(s):  
Data Analysis ◽  
Phase Variation ◽  
Principal Component ◽  
Microarray Data Analysis ◽  
Alignment Algorithm ◽  
Data Set ◽  
Peak Alignment ◽  
Maldi Tof ◽  
Biological Interest ◽  
Phase Variations

The use of MALDI-TOF mass spectrometry as a means of analyzing the proteome has been evaluated extensively in recent years. One of the limitations of this technique that has impeded the development of robust data analysis algorithms is the variability in the location of protein ion signals along the x-axis. We studied technical variations of MALDI-TOF measurements in the context of proteomics profiling. By acquiring a benchmark data set with five replicates, we estimated 76% to 85% of the total variance is due to phase variation. We devised a lobster plot, so named because of the resemblance to a lobster claw, to help detect the phase variation in replicates. We also investigated a peak alignment algorithm to remove the phase variation. This operation is analogous to the normalization step in microarray data analysis. Only after this critical step can features of biological interest be clearly revealed. With the help of principal component analysis, we demonstrated that after peak alignment, the differences among replicates are reduced. We compared this approach to peak alignment with a model-based calibration approach in which there was known information about peaks in common among all spectra. Finally, we examined the potential value at each point in an analysis pipeline of having a set of methods available that includes parametric, semiparametric and nonparametric methods; among such methods are those that benefit from the use of prior information.

scholarly journals Multi-season optical modulation phased with the orbit of the super-Earth 55 Cancri e

2019 ◽  
Vol 631 ◽  
pp. A129 ◽  
Author(s):  
S. Sulis ◽  
D. Dragomir ◽  
M. Lendl ◽  
V. Bourrier ◽  
B. O. Demory ◽  
...  
Keyword(s):  
Orbital Period ◽  
Phase Modulation ◽  
Rotation Period ◽  
Stray Light ◽  
Optical Modulation ◽  
Optical Wavelengths ◽  
A New Technique ◽  
Detailed Interpretation ◽  
Systematic Noise ◽  
Geometric Albedo

Context. 55 Cnc e is a transiting super-Earth orbiting a solar-like star with an orbital period of ~17.7 h. In 2011, using the Microvariability and Oscillations in Stars (MOST) space telescope, a quasi-sinusoidal modulation in flux was detected with the same period as the planetary orbit. The amplitude of this modulation was too large to be explained as the change in light reflected or emitted by the planet. Aims. The MOST telescope continued to observe 55 Cnc e for a few weeks per year over five years (from 2011 to 2015), covering 143 individual transits. This paper presents the analysis of the observed phase modulation throughout these observations and a search for the secondary eclipse of the planet. Methods. The most important source of systematic noise in MOST data is due to stray-light reflected from the Earth, which is modulated with both the orbital period of the satellite (101.4 min) and the Earth’s rotation period. We present a new technique to deal with this source of noise, which we combined with standard detrending procedures for MOST data. We then performed Markov chain Monte Carlo analyses of the detrended light curves, modeling the planetary transit and phase modulation. Results. We find phase modulations similar to those seen in 2011 in most of the subsequent years; however, the amplitude and phase of maximum light are seen to vary, from year to year, from 113 to 28 ppm and from 0.1 to 3.8 rad. The secondary eclipse is not detected, but we constrain the geometric albedo of the planet to less than 0.47 (2σ). Conclusions. While we cannot identify a single origin of the observed optical modulation, we propose a few possible scenarios. Those include star-planet interaction, such as coronal rains and spots rotating with the motion of the planet along its orbit, or the presence of a transiting circumstellar torus of dust. However, a detailed interpretation of these observations is limited by their photometric precision. Additional observations at optical wavelengths could measure the variations at higher precision, contribute to uncovering the underlying physical processes, and measure or improve the upper limit on the albedo of the planet.

Instantaneous phase variation for seismic velocity monitoring from ambient noise at the exploration scale

Geophysics ◽  
2012 ◽  
Vol 77 (4) ◽  
pp. Q37-Q44 ◽  
Author(s):  
Margherita Corciulo ◽  
Philippe Roux ◽  
Michel Campillo ◽  
Dominique Dubucq
Keyword(s):  
Seismic Noise ◽  
Seismic Velocity ◽  
Phase Measurement ◽  
Signal To Noise Ratio ◽  
Phase Variation ◽  
Computation Time ◽  
Real Data ◽  
Velocity Change ◽  
Data Set ◽  
Instantaneous Phase

Recent studies in geophysics have investigated the use of seismic-noise correlations to measure weak-velocity variations from seismic-noise recordings. However, classically, the existing algorithms used to monitor medium velocities need extensive efforts in terms of computation time. This implies that these techniques are not appropriate at smaller scales in an exploration context when continuous data sets on dense arrays of sensors have to be analyzed. We applied a faster technique that allows the monitoring of small velocity changes from the instantaneous phase measurement of the seismic-noise crosscorrelation functions. We performed comparisons with existing algorithms using synthetic signals. The results we have obtained for a real data set show that the statistical distribution of the velocity-change estimates provides reliable measurements, despite the low signal-to-noise ratio obtained from the noise-correlation process.

scholarly journals An investigation of the very rare $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ decay

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
E. Cortina Gil ◽  
◽  
A. Kleimenova ◽  
E. Minucci ◽  
S. Padolski ◽  
...  
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
New Physics ◽  
Single Event ◽  
Data Set ◽  
Upper Limit ◽  
The Standard Model

Abstract The NA62 experiment reports an investigation of the $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ K + → π + ν ν ¯ mode from a sample of K+ decays collected in 2017 at the CERN SPS. The experiment has achieved a single event sensitivity of (0.389 ± 0.024) × 10−10, corresponding to 2.2 events assuming the Standard Model branching ratio of (8.4 ± 1.0) × 10−11. Two signal candidates are observed with an expected background of 1.5 events. Combined with the result of a similar analysis conducted by NA62 on a smaller data set recorded in 2016, the collaboration now reports an upper limit of 1.78 × 10−10 for the $$ {K}^{+}\to {\pi}^{+}\nu \overline{\nu} $$ K + → π + ν ν ¯ branching ratio at 90% CL. This, together with the corresponding 68% CL measurement of ($$ {0.48}_{-0.48}^{+0.72} $$ 0.48 − 0.48 + 0.72 ) × 10−10, are currently the most precise results worldwide, and are able to constrain some New Physics models that predict large enhancements still allowed by previous measurements.

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