scholarly journals Searching for reflected light from τ Bootis b with high-resolution ground-based spectroscopy: Approaching the 10−5 contrast barrier

2018 ◽  
Vol 610 ◽  
pp. A47 ◽  
Author(s):  
H. J. Hoeijmakers ◽  
I. A. G. Snellen ◽  
S. E. van Terwisga
Keyword(s):  
Meta Analysis ◽  
Phase Curve ◽  
High Dispersion ◽  
Stellar Spectrum ◽  
Hot Jupiters ◽  
Reflected Light ◽  
Theoretical Predictions ◽  
The Subject ◽  
Host Stars ◽  
Expected Signal

Context. It is challenging to measure the starlight reflected from exoplanets because of the extreme contrast with their host stars. For hot Jupiters, this contrast is in the range of 10−6 to 10−4, depending on their albedo, radius and orbital distance. Searches for reflected light have been performed since the first hot Jupiters were discovered, but with very limited success because hot Jupiters tend to have low albedo values due to the general absence of reflective cloud decks. Aims. The aim of this study is to search for reflected light from τ Boo b, a hot Jupiter with one of the brightest host stars. Since its discovery in 1997, it has been the subject of several reflected-light searches using high-dispersion spectroscopy. Here we aim to combine these data in to a single meta-analysis. Methods. We analysed more than 2000 archival high-dispersion spectra obtained with the UVES, ESPaDOnS, NARVAL UES and HARPS-N spectrographs during various epochs between 1998 and 2013. Each spectrum was first cleaned of the stellar spectrum and subsequently cross-correlated with a PHOENIX model spectrum. These were then Doppler shifted to the planet rest-frame and co-added in time, weighted according to the expected signal-to-noise of the planet signal. Results. We reach a 3σ upper limit of the planet-to-star contrast of 1.5 × 10−5. Assuming a planet radius of 1.15 RJ, this corresponds to an optical albedo of 0.12 between 400–700 nm. A low albedo is in line with secondary eclipse and phase curve observations of other hot Jupiters using space-based observatories, as well as theoretical predictions of their reflective properties.

scholarly journals Three short-period Jupiters from TESS

2020 ◽  
Vol 639 ◽  
pp. A76 ◽  
Author(s):  
L. D. Nielsen ◽  
R. Brahm ◽  
F. Bouchy ◽  
N. Espinoza ◽  
O. Turner ◽  
...  
Keyword(s):  
Stellar System ◽  
Phase Curve ◽  
Mass Determination ◽  
Tidal Dissipation ◽  
Giant Star ◽  
Hot Jupiters ◽  
Short Period ◽  
Host Stars ◽  
Interesting System

We report the confirmation and mass determination of three hot Jupiters discovered by the Transiting Exoplanet Survey Satellite (TESS) mission: HIP 65Ab (TOI-129, TIC-201248411) is an ultra-short-period Jupiter orbiting a bright (V = 11.1 mag) K4-dwarf every 0.98 days. It is a massive 3.213 ± 0.078 MJ planet in a grazing transit configuration with an impact parameter of b = 1.17−0.08+0.10. As a result the radius is poorly constrained, 2.03−0.49+0.61RJ. The planet’s distance to its host star is less than twice the separation at which it would be destroyed by Roche lobe overflow. It is expected to spiral into HIP 65A on a timescale ranging from 80 Myr to a few gigayears, assuming a reduced tidal dissipation quality factor of Qs′ = 107 − 109. We performed a full phase-curve analysis of the TESS data and detected both illumination- and ellipsoidal variations as well as Doppler boosting. HIP 65A is part of a binary stellar system, with HIP 65B separated by 269 AU (3.95 arcsec on sky). TOI-157b (TIC 140691463) is a typical hot Jupiter with a mass of 1.18 ± 0.13 MJ and a radius of 1.29 ± 0.02 RJ. It has a period of 2.08 days, which corresponds to a separation of just 0.03 AU. This makes TOI-157 an interesting system, as the host star is an evolved G9 sub-giant star (V = 12.7). TOI-169b (TIC 183120439) is a bloated Jupiter orbiting a V = 12.4 G-type star. It has a mass of 0.79 ±0.06 MJ and a radius of 1.09−0.05+0.08RJ. Despite having the longest orbital period (P = 2.26 days) of the three planets, TOI-169b receives the most irradiation and is situated on the edge of the Neptune desert. All three host stars are metal rich with [Fe / H] ranging from 0.18 to0.24.

scholarly journals Magnetism and activity of planet hosting stars

2015 ◽  
Vol 11 (S320) ◽  
pp. 357-366
Author(s):  
Jason T. Wright ◽  
Brendan P. Miller
Keyword(s):  
Magnetic Activity ◽  
Magnetic Interactions ◽  
Activity Levels ◽  
Hot Jupiters ◽  
Tidal Interactions ◽  
Coronal Activity ◽  
Induce Activity ◽  
Star Ages ◽  
Host Stars ◽  
Expected Signal

AbstractThe magnetic activity levels of planet host stars may differ from that of stars not known to host planets in several ways. Hot Jupiters may induce activity in their hosts through magnetic interactions, or through tidal interactions by affecting their host's rotation or convection. Measurements of photospheric, chromospheric, or coronal activity might then be abnormally high or low compared to control stars that do not host hot Jupiters, or might be modulated at the planet's orbital period. Such detections are complicated by the small amplitude of the expected signal, by the fact that the signals may be transient, and by the difficulty of constructing control samples due to exoplanet detection biases and the uncertainty of field star ages. We review these issues, and discuss avenues for future progress in the field.

QCD at Fixed Order: Processes

2018 ◽  
Author(s):  
John Campbell ◽  
Joey Huston ◽  
Frank Krauss
Keyword(s):  
Hadron Collider ◽  
Detailed Comparison ◽  
Theoretical Description ◽  
Higgs Bosons ◽  
Final States ◽  
Collider Physics ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Fixed Order ◽  
The Subject

At the core of any theoretical description of hadron collider physics is a fixed-order perturbative treatment of a hard scattering process. This chapter is devoted to a survey of fixed-order predictions for a wide range of Standard Model processes. These range from high cross-section processes such as jet production to much more elusive reactions, such as the production of Higgs bosons. Process by process, these sections illustrate how the techniques developed in Chapter 3 are applied to more complex final states and provide a summary of the fixed-order state-of-the-art. In each case, key theoretical predictions and ideas are identified that will be the subject of a detailed comparison with data in Chapters 8 and 9.

scholarly journals Influence of Personal and Task Interdependence on Task Conflict and Team Effectiveness

2016 ◽  
Vol 10 (4) ◽  
pp. 95 ◽  
Author(s):  
Jeffrey Lawrence D'Silva ◽  
Adriana Ortega ◽  
Abdul Hadi Sulaiman
Keyword(s):  
Team Effectiveness ◽  
Meta Analysis ◽  
Task Interdependence ◽  
Task Conflict ◽  
Personality Factors ◽  
Team Members ◽  
Information And Communication ◽  
The Subject ◽  
The Given ◽  
And Task

<p>Undeniably working in teams are important as tasks are getting more complicated and advanced as a result of globalization and the speedy growth of information and communication technology. This calls for effectiveness from team members to complete all interdependent sub-tasks to ensure that the given tasks achieve its’ desired objectives. During the process of implementing the tasks, teams are poised to face conflicts that may derail the completion of tasks. The focus of this paper is to examine the influence of personality factors and task interdependence on task conflict and team effectiveness. A meta-analysis on past studies was carried out to gather data on the subject matter. The input obtained will be pertinent for future researchers in further understanding the complexities associated with task interdependence and personality on task conflict and team effectiveness.</p>

scholarly journals The research method of conceptual frameworks. The case of Pygmalion effect: A leadership style or self-fulfilling prophecy?

2019 ◽  
Vol 9 (3) ◽  
pp. 487-510
Author(s):  
Sejla Almadi
Keyword(s):  
Leadership Style ◽  
Meta Analysis ◽  
Educational Technology Research ◽  
Research Subject ◽  
Conceptual Frameworks ◽  
Pygmalion Effect ◽  
Less Is More ◽  
Database Research ◽  
The Subject

Conceptual frameworks are conjectural/hypothetical research tools that are particularly important and widely used in the disciplined inquiry, including educational (technology) research. However, there is a lack of guidance on how to construct them. Hence, the objective of the current research was to provide a methodological perspective through a case study on how to develop such a framework for deductive research with a complex research subject. To this end, a five-step technique was constructed and implemented: text database, research panorama, authors’ network and thread, location, and definition. The case of Pygmalion effect was actual and significant as a recent meta-analysis found it to have an outstanding impact, among other leadership interventions, and relevant to educational research as it was first experimented in educational context. The conclusion found the five steps to be intertwined as they were built upon each other, carried the thread forward and opened it up deeper and closer to the research subject by each section. The errors and limitations involved uniqueness, availability, less is more, meaningfulness, approach, and space. Hence, the recommendations were defined as the regard for the complexity of the research subject and the approach to which the defined steps were delegated, the preliminary search on the most up-to-date academic papers on the subject, the only necessary number of collected sources and classes, the sense-making in implementing the steps, and the adaptation to longer essays, theses, or to prepare the foundation of research proposals.

scholarly journals Role of host star variability in the detectability of planetary phase curves

2019 ◽  
Vol 621 ◽  
pp. A44
Author(s):  
D. Hidalgo ◽  
R. Alonso ◽  
E. Pallé
Keyword(s):  
Effective Temperature ◽  
Thermal Emission ◽  
Total Duration ◽  
Phase Curve ◽  
Single Orbit ◽  
Reflected Light ◽  
Planetary Orbits ◽  
Minimum Number ◽  
Temperature Ranges ◽  
Low Amplitude

Phase curves, or the change in observed illumination of the planet as it orbits around its host star, help us to characterize their atmospheres. However, the variability of the host star can make their detection challenging. The presence of starspots, faculae, flares, and rotational effects introduce brightness variations that can hide other flux variations related to the presence of an exoplanet: ellipsoidal variation, Doppler boosting, and a combination of reflected light and thermal emission from the planet. Here we present a study to quantify the effect of stellar variability on the detectability of phase curves in the optical. In the first stage we simulated ideal data, with different white noise levels, and with cadences and total duration matching a quarter of the Kepler mission. We performed injection and recovery tests to evaluate the minimum number of planetary orbits that need to be observed in order to determine the amplitude of the phase curve with an accuracy of 15%. We also evaluate the effect of a simplistic stellar variability signal with low amplitude in order to provide strong constraints on the minimum number of orbits needed under these ideal conditions. In the second stage we applied these methods to data from Q9 of the Kepler mission, known for its low instrumental noise. The injection and recovery tests are performed on a selected sample of the less noisy stars in different effective temperature ranges. Even for the shortest explored planet period of 1 day, we find that observing a single orbit of the planet fails to detect accurately more than 90% of the inserted amplitude. The best recovery rates, close to 48%, are obtained after 10 orbits of a 1 day period planet with the largest explored amplitude of 150 ppm. The temperature range of the host stars providing better recovery ratios is 5500 K < Teff < 6000 K. Our results provide guidelines to selecting the best targets in which phase curves can be measured to the greatest accuracy, given the variability and effective temperature of its host star, which is of interest for the upcoming TESS, CHEOPS, and PLATO space missions.

scholarly journals An individual participant data (IPD) meta-analysis on the attachment network to multiple caregivers

2020 ◽  
Author(s):  
Or Dagan ◽  
Pasco Fearon ◽  
Carlo Schuengel ◽  
Marije Verhage ◽  
Glenn I. Roisman ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Developmental Outcomes ◽  
Research Synthesis ◽  
Individual Participant Data ◽  
Attachment Relationship ◽  
Attachment Research ◽  
Individual Participant ◽  
The Subject ◽  
Meta Analyses

Since the seminal 1992 paper by van IJzendoorn, Sagi, and Lambermon, putting forward the “The multiple caretaker paradox”, relatively little attention has been given to the potential joint effects of the role early attachment network to mother and father play in development. Recently, Dagan and Sagi-Schwartz (2018) have published a paper that attempts to revive this unsettled issue, calling for research on the subject and offering a framework for posing attachment network hypotheses. This Collaboration for Attachment Research Synthesis project attempts to use an Individual Participant Data meta-analyses to test the hypotheses put forward in Dagan and Sagi-Schwartz (2018). Specifically, we test (a) whether the number of secure attachments (0,1, or 2) matter in predicting a range of developmental outcomes, and (b) whether the quality of attachment relationship with one parent contributes more than the other to these outcomes.

scholarly journals PSYCHOLOGY OF RESPONSIBILITY IN THE WORKS OF SCIENTISTS OF THE OMSK STATE UNIVERSITY: HISTORY, RESULTS, PROSPECTS FOR RESEARCH

2020 ◽  
pp. 11-23
Author(s):  
Lyudmila Ivanovna Dementiy ◽  
Olga Yuryevna Grogoleva
Keyword(s):  
Meta Analysis ◽  
Age Groups ◽  
State University ◽  
University History ◽  
The Subject ◽  
Life Path

The article analyzes the results of responsibility research conducted at the Faculty of Psychology of Dostoevsky Omsk State University for more than 15 years. One of the scientific areas of study in the stated context is the implementation of the ideas of typological and subjective approaches to the study of responsibility as a property of an individual. The analysis integrates the results of the construction of typologies of responsibility, built on different age groups and in combination with the problem of building the life path, solving life contradictions and perfectionism. The Meta-analysis made it possible to confirm the main provisions of the concept of responsibility as a property of the subject of life and indicate possible ways of its development.

scholarly journals The particle and magnetic environments surrounding close-in exoplanets

2015 ◽  
Vol 11 (S320) ◽  
pp. 397-402
Author(s):  
A. A. Vidotto ◽  
R. Fares ◽  
M. Jardine ◽  
C. Moutou ◽  
J.-F. Donati
Keyword(s):  
Magnetic Fields ◽  
Radio Emission ◽  
Magnetic Field Intensity ◽  
Three Dimensional ◽  
Stellar Winds ◽  
Local Conditions ◽  
Hot Jupiters ◽  
The Earth ◽  
Weather Events ◽  
Host Stars

AbstractThe proper characterisation of stellar winds is essential for the study of propagation of eruptive events (flares, coronal mass ejections) and the study of space weather events on exoplanets. Here, we quantitatively investigate the nature of the stellar winds surrounding the hot Jupiters HD46375b, HD73256b, HD102195b, HD130322b, HD179949b. We simulate the three-dimensional winds of their host stars, in which we directly incorporate their observed surface magnetic fields. With that, we derive the wind properties at the position of the hot-Jupiters’ orbits (temperature, velocity, magnetic field intensity and pressure). We show that the exoplanets studied here are immersed in a local stellar wind that is much denser than the local conditions encountered around the solar system planets (e.g., 5 orders of magnitude denser than the conditions experienced by the Earth). The environment surrounding these exoplanets also differs in terms of dynamics (slower stellar winds, but higher Keplerian velocities) and ambient magnetic fields (2 to 3 orders of magnitude larger than the interplanetary medium surrounding the Earth). The characterisation of the host star's wind is also crucial for the study of how the wind interacts with exoplanets. For example, we compute the exoplanetary radio emission that is released in the wind-exoplanet interaction. For the hot-Jupiters studied here, we find radio fluxes ranging from 0.02 to 0.13 mJy. These fluxes could become orders of magnitude higher when stellar eruptions impact exoplanets, increasing the potential of detecting exoplanetary radio emission.

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