scholarly journals Extra-solar Planets: Clues to Planetary Formation

2004 ◽  
Vol 219 ◽  
pp. 311-322 ◽  
Author(s):  
Nuno C. Santos ◽  
Michel Mayor ◽  
Dominique Naef ◽  
Francesco Pepe ◽  
Didier Queloz ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Radial Velocity ◽  
Crucial Role ◽  
Giant Planet ◽  
Planetary Systems ◽  
Current Status ◽  
Planetary Formation ◽  
Orbital Elements ◽  
Host Stars

Radial velocity surveys have revealed up to now about 115 extra-solar planets, among which a few multi-planetary systems. The discovered planets present a wide variety of orbital elements and masses, which are raising many problems and questions regarding the processes involved in their formation. The statistical analysis of the distributions of orbital elements, planetary masses, and relations between these, is however already giving some strong constraints on the formation of the planetary systems. Furthermore, the study of the planet host stars has revealed the crucial role of the stellar metallicity on the giant planet formation. In this paper we will review the current status of the research on this subject.

scholarly journals The HoSTS Project: A Homogeneous Study of Transiting Systems

2013 ◽  
Vol 8 (S299) ◽  
pp. 285-286
Author(s):  
Yilen Gómez Maqueo Chew ◽  
Francesca Faedi ◽  
Leslie Hebb ◽  
Don Pollacco ◽  
Keivan Stassun ◽  
...  
Keyword(s):  
Pilot Study ◽  
Physical Properties ◽  
Planetary Systems ◽  
Planetary Formation ◽  
Empirical Correlations ◽  
Large Sample ◽  
Fundamental Properties ◽  
Homogeneous Set ◽  
Formation And Evolution ◽  
Host Stars

AbstractThe Homogeneous Study of Transiting Systems (HoSTS) will derive a consistent and homogeneous set of both the stellar and planetary physical properties for a large sample of bright transiting planetary systems with confirmed planetary masses and measured radii. Our resulting catalogs of the fundamental properties of these bright planets and their host stars will enable us to explore empirical correlations that will lead to a better understanding of planetary formation and evolution. We present our pilot study of the planet-hosting star WASP-13, and the framework of our project which will allow for the identification of true relationships among the physical properties of the systems from any systematics.

scholarly journals Oxidative Role of Aflatoxin B1 on the Liver of Wheat Milling Workers

2014 ◽  
Vol 2 (1) ◽  
pp. 141-146 ◽  
Author(s):  
Amal Saad-Hussein ◽  
Mohgah Sh. Abdalla ◽  
Wafaa Gh. Shousha ◽  
Gehan Moubarz ◽  
Aya H. Mohamed
Keyword(s):  
Oxidative Stress ◽  
Statistical Analysis ◽  
Vitamin C ◽  
Aflatoxin B1 ◽  
Crucial Role ◽  
Case Control Study ◽  
Liver Enzymes ◽  
Case Control ◽  
Control Study

Aim: The study aimed to estimate oxidative role of aflatoxin B1 (AFB1) on the liver in wheat milling workers. Materials and Methods: Case-control study was conducted to compare between the levels of AFB1/albumin (AFB1/alb), liver enzymes (ALT, AST, GGT, and ALP), P53, MDA, GST, SOD, zinc and vitamin C in 35 wheat milling workers and 40 control subjects. Results: Statistical analysis revealed that ALT, AST, GGT, ALP, P53, MDA, GST and SOD in workers were significantly elevated compared to their controls. In the milling workers, there were significant correlations between MDA levels and the levels of AST, GGT, and P53, while, P53 was inversely correlated with GST and SOD activities. There were significant correlations between Zn levels and GGT, GST and SOD activities, between vitamin C and GST activities, and vitamin C inversely correlated with MDA. Conclusion: The present study concluded that the oxidative stress of AFB1 elevated the MDA and the liver enzymes in wheat milling workers. GST has a crucial role in the detoxification of aflatoxin and SOD as a scavenger antioxidant increased in the workers to overcome the oxidative toxic effects of AFB1 on the liver of the workers, and roles of Zn and vitamin C were significant in activation of these processes.

scholarly journals Heavy Metal Rules. I. Exoplanet Incidence and Metallicity

Geosciences ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 105 ◽  
Author(s):  
Vardan Adibekyan
Keyword(s):  
Building Materials ◽  
Giant Planet ◽  
High Mass ◽  
Different Types ◽  
Lively Debate ◽  
Formation And Evolution ◽  
The Subject ◽  
Host Stars ◽  
Homogeneous Data

The discovery of only a handful of exoplanets required establishing a correlation between giant planet occurrence and metallicity of their host stars. More than 20 years have already passed from that discovery, however, many questions are still under lively debate: (1) What is the origin of that relation?; (2) What is the exact functional form of the giant planet–metallicity relation (in the metal-poor regime)?; and (3) Does such a relation exist for terrestrial planets? All of these questions are very important for our understanding of the formation and evolution of (exo)planets of different types around different types of stars and are the subject of the present manuscript. Besides making a comprehensive literature review about the role of metallicity on the formation of exoplanets, I also revisited most of the planet–metallicity related correlations reported in the literature using a large and homogeneous data provided by the SWEET-Cat catalog. This study led to several new results and conclusions, two of which I believe deserve to be highlighted in the abstract: (i) the hosts of sub-Jupiter mass planets (∼0.6–0.9 M♃) are systematically less metallic than the hosts of Jupiter-mass planets. This result might be related to the longer disk lifetime and the higher amount of planet building materials available at high metallicities, which allow a formation of more massive Jupiter-like planets; (ii) contrary to the previous claims, our data and results do not support the existence of a breakpoint planetary mass at 4 M♃ above and below which planet formation channels are different. However, the results also suggest that planets of the same (high) mass can be formed through different channels depending on the (disk) stellar mass i.e., environmental conditions.

scholarly journals Asteroseismology of exoplanet host stars

2015 ◽  
Vol 11 (A29B) ◽  
pp. 620-627
Author(s):  
Daniel Huber
Keyword(s):  
Radial Velocity ◽  
Planetary Systems ◽  
Precise Determination ◽  
Spin Orbit ◽  
Velocity Measurements ◽  
Fundamental Properties ◽  
Future Space ◽  
Host Stars

AbstractAsteroseismology is among the most powerful observational tools to determine fundamental properties of stars. Space-based photometry has recently enabled the systematic detection of oscillations in exoplanet host stars, allowing a combination of asteroseismology with transit and radial-velocity measurements to characterize planetary systems. In this contribution I will review the key synergies between asteroseismology and exoplanet science such as the precise determination of radii and ages of exoplanet host stars, as well as applications of asteroseismology to measure spin-orbit inclinations in multiplanet systems and orbital eccentricities of small planets. Finally I will give a brief outlook on asteroseismic studies of exoplanet hosts with current and future space-based missions such as K2 and TESS.

scholarly journals SOPHIE velocimetry of Kepler transit candidates

2019 ◽  
Vol 623 ◽  
pp. A104 ◽  
Author(s):  
G. Hébrard ◽  
A. S. Bonomo ◽  
R. F. Díaz ◽  
A. Santerne ◽  
N. C. Santos ◽  
...  
Keyword(s):  
Radial Velocity ◽  
Orbital Period ◽  
Planetary System ◽  
Giant Planet ◽  
Eccentric Orbit ◽  
Promising Candidate ◽  
Single Star ◽  
Orbital Periods ◽  
Host Stars

Whereas thousands of transiting giant exoplanets are known today, only a few are well characterized with long orbital periods. Here we present KOI-3680b, a new planet in this category. First identified by the Kepler team as a promising candidate from the photometry of the Kepler spacecraft, we establish here its planetary nature from the radial velocity follow-up secured over 2 yr with the SOPHIE spectrograph at Observatoire de Haute-Provence, France. The combined analysis of the whole dataset allows us to fully characterize this new planetary system. KOI-3680b has an orbital period of 141.2417 ± 0.0001 days, a mass of 1.93 ± 0.20 MJup, and a radius of 0.99 ± 0.07 RJup. It exhibits a highly eccentric orbit (e = 0.50 ± 0.03) around an early G dwarf. KOI-3680b is the transiting giant planet with the longest period characterized so far around a single star; it offers opportunities to extend studies which were mainly devoted to exoplanets close to their host stars, and to compare both exoplanet populations.

scholarly journals IUE and Massive Binaries

1991 ◽  
Vol 143 ◽  
pp. 237-244
Author(s):  
D. J. Stickland
Keyword(s):  
Radial Velocity ◽  
Massive Stars ◽  
Optical Data ◽  
Orbital Elements ◽  
Ultraviolet Observations ◽  
Complementary Value

The role of IUE in the determination of orbital elements of massive stars is reviewed, emphasising the complementary value of ultraviolet observations when combined with archival optical data. Results on eight systems are described and the potential of the IUE archive for radial velocity work in general is advocated.

Psychological Resilience Provides No Independent Protection From Suicidal Risk

Crisis ◽  
2016 ◽  
Vol 37 (2) ◽  
pp. 130-139 ◽  
Author(s):  
Danica W. Y. Liu ◽  
A. Kate Fairweather-Schmidt ◽  
Richard Burns ◽  
Rachel M. Roberts ◽  
Kaarin J. Anstey
Keyword(s):  
Risk Factors ◽  
Well Being ◽  
Current Status ◽  
Psychological Resilience ◽  
Cross Sectional ◽  
Life Project ◽  
Resilience Factors ◽  
First Time

Abstract. Background: Little is known about the role of resilience in the likelihood of suicidal ideation (SI) over time. Aims: We examined the association between resilience and SI in a young-adult cohort over 4 years. Our objectives were to determine whether resilience was associated with SI at follow-up or, conversely, whether SI was associated with lowered resilience at follow-up. Method: Participants were selected from the Personality and Total Health (PATH) Through Life Project from Canberra and Queanbeyan, Australia, aged 28–32 years at the first time point and 32–36 at the second. Multinomial, linear, and binary regression analyses explored the association between resilience and SI over two time points. Models were adjusted for suicidality risk factors. Results: While unadjusted analyses identified associations between resilience and SI, these effects were fully explained by the inclusion of other suicidality risk factors. Conclusion: Despite strong cross-sectional associations, resilience and SI appear to be unrelated in a longitudinal context, once risk/resilience factors are controlled for. As independent indicators of psychological well-being, suicidality and resilience are essential if current status is to be captured. However, the addition of other factors (e.g., support, mastery) makes this association tenuous. Consequently, resilience per se may not be protective of SI.

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