scholarly journals Asteroseismic and orbital analysis of the triple star system HD 188753 observed by Kepler

2018 ◽  
Vol 617 ◽  
pp. A2 ◽  
Author(s):  
F. Marcadon ◽  
T. Appourchaux ◽  
J. P. Marques

Context. The NASA Kepler space telescope has detected solar-like oscillations in several hundreds of single stars, thereby providing a way to determine precise stellar parameters using asteroseismology. Aims. In this work, we aim to derive the fundamental parameters of a close triple star system, HD 188753, for which asteroseismic and astrometric observations allow independent measurements of stellar masses. Methods. We used six months of Kepler photometry available for HD 188753 to detect the oscillation envelopes of the two brightest stars. For each star, we extracted the individual mode frequencies by fitting the power spectrum using a maximum likelihood estimation approach. We then derived initial guesses of the stellar masses and ages based on two seismic parameters and on a characteristic frequency ratio, and modelled the two components independently with the stellar evolution code CESTAM. In addition, we derived the masses of the three stars by applying a Bayesian analysis to the position and radial-velocity measurements of the system. Results. Based on stellar modelling, the mean common age of the system is 10.8 ± 0.2 Gyr and the masses of the two seismic components are MA = 0.99 ± 0.01 M⊙ and MBa = 0.86 ± 0.01 M⊙. From the mass ratio of the close pair, MBb/MBa = 0.767 ± 0.006, the mass of the faintest star is MBb = 0.66 ± 0.01 M⊙ and the total seismic mass of the system is then Msyst = 2.51 ± 0.02 M⊙. This value agrees perfectly with the total mass derived from our orbital analysis, Msyst = 2.51−0.18+0.20 M⊙, and leads to the best current estimate of the parallax for the system, π = 21.9 ± 0.2 mas. In addition, the minimal relative inclination between the inner and outer orbits is 10.9° ± 1.5°, implying that the system does not have a coplanar configuration.

2020 ◽  
Vol 496 (2) ◽  
pp. 1355-1368
Author(s):  
J-L Halbwachs ◽  
F Kiefer ◽  
Y Lebreton ◽  
H M J Boffin ◽  
F Arenou ◽  
...  

ABSTRACT Double-lined spectroscopic binaries (SB2s) are one of the main sources of stellar masses, as additional observations are only needed to give the inclinations of the orbital planes in order to obtain the individual masses of the components. For this reason, we are observing a selection of SB2s using the SOPHIE spectrograph at the Haute-Provence observatory in order to precisely determine their orbital elements. Our objective is to finally obtain masses with an accuracy of the order of one per cent by combining our radial velocity (RV) measurements and the astrometric measurements that will come from the Gaia satellite. We present here the RVs and the re-determined orbits of 10 SB2s. In order to verify the masses, we will derive from Gaia, we obtained interferometric measurements of the ESO VLTI for one of these SB2s. Adding the interferometric or speckle measurements already published by us or by others for four other stars, we finally obtain the masses of the components of five binary stars, with masses ranging from 0.51 to 2.2 solar masses, including main-sequence dwarfs and some more evolved stars whose location in the HR diagram has been estimated.


1997 ◽  
Vol 485 (1) ◽  
pp. 350-358 ◽  
Author(s):  
Ning Liu ◽  
Douglas R. Gies ◽  
Ying Xiong ◽  
Reed L. Riddle ◽  
William G. Bagnuolo, Jr. ◽  
...  

1998 ◽  
Vol 11 (1) ◽  
pp. 419-420
Author(s):  
David W. Latham

What is known about the masses of main-sequence stars from the analysis of binary orbits? Double-lined eclipsing binaries are the main source of very precise stellar masses and radii (e.g. Andersen 1997), contributing more than 100 determinations with better than 2% precision over the range 0.6 to 20 Mʘ. For lower-mass stars we are forced to turn to nearby systems with astrometric orbits (e.g. Henry et al. 1993). Not only is the number of good mass determinations from such systems smaller, but also the precision is generally poorer. We are approaching an era when interferometers should have a major impact by supplying good astrometric orbits for dozens of double-lined systems. Already we are beginning to see the sorts of results to expect from this (e.g. Torres et al. 1997). Figure 1. Mass vs. absolute V magnitude for eclipsing binaries (circles) and nearby astrometric binaries (squares) Figure 1 is an updated version of a diagram presented by Henry et al. (1993, their Figure 2). It shows the general run of mass determinations from about 10 Mʘ down to the substellar limit near 0.075 Mʘ. Ninety of the points in Figure 1 are for eclipsing binary masses from Andersen’s review (1991) and are plotted as open circles. The results for eclipsing binaries published since 1991 are plotted as 30 filled circles, adopting the same limit of 2% for the mass precision. In most cases the uncertainties are similar to the size of the symbols. Especially noteworthy is the pair of new points for CM Draconis (Metcalfe et al. 1996) with masses near 0.25 Mʘ. Together with the points for YY Geminorum near 0.6 Mʘ, these are the only M dwarfs that have precise mass determinations. For the most part we are forced to rely on nearby stars with astrometric orbits, to fill in the M dwarf region of the diagram. We have used filled squares in Figure 1 for 29 such systems from Henry et al. (1993), updated using 14 new parallaxes from Hipparcos and 4 from the new Yale Parallax Catalog (1995). Gliese 508 is not included, because it is now known to be a triple, while Gliese 67AB, 570BC, and 623AB are not included because there are not yet any direct measurements of the V magnitude difference for these systems.


2009 ◽  
Vol 37 (108) ◽  
pp. 188-217
Author(s):  
Ulrik Schmidt

Keaton and the Masses:This article explores conflicts between individual and mass and the process of massification (i.e. the becoming and unfolding of masses) as comic potential in Buster Keaton’s physical comedies. This comic potential is basically characterized by a formalized and aestheticized reduction of human individuality when confronted with objective, non-human matter. De-individualization plays an important role in modern comedy in general. With his intense focus on massification, though, Keaton is not only one of the first, but also one of the most dedicated investigators of comic de-individualization by purely physical means.The first part of the article considers the complex relations in Keaton between gag and narrative with specific regard to the conflict between the individual and the masses. Furthermore, the basic compositional elements in Keaton’s cinematographic staging of individual-mass conflicts are explored, including deactivation and isolation of the individual in relation to his immediate surroundings.Subsequently, the different forms of massification in Keaton are examined more closely with reference to variation in their comic potential. Here, Keaton’s masses are grouped into three basic forms: In the solid mass—typically materialized in heavy objects and hard surfaces—the comic potential is due to its ability to violently tumble or jam the pacified individual into de-subjectified body mass. In the fluid mass, the comic potential is basically found in the unmanageable character of the soft, formless and constantly transforming phenomenon. In pure accumulation, Keaton focuses on the comic potential of the very formation of masses as a process of accumulation (i.e., the repetitive addition of discrete, more or less identical elements). Here, Keaton’s interest lies above all in the formation of human masses (crowds).The last section considers Keaton’s cinematographic distribution of individual gags on the global scale of the entire film. Here, it is analyzed how Keaton incessantly glues the individual gags together into one large and seamlessly continuous gag. It is thus concluded that not only is each individual gag characterized by massification, but the way the different gags are interrelated throughout Keaton’s films also has a profound mass character.


2021 ◽  
Vol 10 (6) ◽  
Author(s):  
Ketan Patel

A mechanism to generate realistic fermion mass hierarchies based on supersymmetric gauged U(1)_FU(1)F symmetry in flat five-dimensional (5D) spacetime is proposed. The fifth dimension is compactified on S^1/Z_2S1/Z2 orbifold. The standard model fermions charged under the extra abelian symmetry along with their superpartners live in the 5D bulk. Bulk masses of fermions are generated by the vacuum expectation value of N=2N=2 superpartner of U(1)_FU(1)F gauge field, and they are proportional to U(1)_FU(1)F charges of respective fermions. This decides localization of fermions in the extra dimension, which in turn gives rise to exponentially suppressed Yukawa couplings in the effective 4D theory. Anomaly cancellation puts stringent constraints on the allowed U(1)_FU(1)F charges which leads to correlations between the masses of quarks and leptons. We perform an extensive numerical scan and obtain several solutions for anomaly-free U(1)_FU(1)F, which describe the observed pattern of fermion masses and mixing with all the fundamental parameters of order unity. It is found that the possible existence of SM singlet neutrinos substantially improves the spectrum of solutions by offering more freedom in choosing U(1)_FU(1)F charges. The model predicts Z^\primeZ′ boson mediating flavour violating interactions in both the quark and lepton sectors with the couplings which can be explicitly determined from the Yukawa couplings.


2021 ◽  
Vol 1 (6) ◽  
pp. 91-97
Author(s):  
Yury V. Lebedev ◽  

The article reveals the deep connections of the “people’s thought” and Tolstoy’s philosophy of history in “War and Peace” with the theological and literary-critical works of A.S. Khomyakova. The author of the work analyzes the dispute between Tolstoy and the cult of an outstanding personality, with the Hegelian understanding of his role in the historical process. Tolstoy is alien to the Hegelian rise of “great personalities” over the masses, the Hegelian liberation of the “genius” from moral control and evaluation. Tolstoy believes that it is not an exceptional personality, but the life of the people that turns out to be the most sensitive organism, catching the will of Providence, intuitively sensing the hidden meaning of the historical movement. Anticipating Tolstoy, Khomyakov sharply criticizes the cult of personality in the church hierarchy, the Catholic dogma of papal infallibility, of the unconditional authority of an individual in matters of conscience and faith. Khomyakov reveals deep religious roots that feed the centuries-old Western enmity towards Russia. The article proves that Tolstoy is close to Khomyakov’s idea that Divine Providence overshadows with its grace only the believing people, united into a single organism by Christian love, that the epic basis of “War and Peace” is anticipated in Khomyakov’s literary-critical works “Glinka’s Opera ‘Life for Tsar’”, “On the Possibility of the Russian Art School”, “Ivanov’s Painting. Letter to the editor of ‘Russian Beseda’”. The article proves that “War and Peace” overcomes the conflict between the individual and society, the hero and the people, and reveals the epic horizons lost in the Western European novel.


Author(s):  
Donald J. Munro

Chinese Marxism is a mixture of elements from Confucianism, German Marxism, Soviet Leninism and China’s own guerrilla experience. Because Mao Zedong (1893–1976) was in power longer than any other Chinese communist, the phrase ‘Chinese Marxism’ is commonly used to refer to Mao’s own evolving mixture of ideas from these sources. However, the advocates of Chinese Marxism have come from many different factional backgrounds and have tended to emphasize different aspects in their own thinking. Even Maoism reflects many minds. For example, Mao’s two most famous essays, ‘Shijianlun’ (‘On Practice’) and ‘Maodunlun’ (‘On Contradiction’) (1937) drew heavily from Ai Siqi, the author of the popular philosophical work Dazhong zhexue (Philosophy for the Masses) (1934). The goals of the Chinese Marxists included the salvation of China from its foreign enemies and the strengthening of the country through modernization. Accordingly, they selected from other systematic theories those doctrines that appeared to facilitate those goals, and then paired these doctrines with others from theories that were sometimes incompatible. One should not, therefore, look for logical consistency in the relations between the ideas that the Chinese Marxists drew from these various sources. The foundation of Chinese Marxism was undoubtedly Marx’s materialist conception of history, and the concepts of class struggle and control of the forces of production shaped the thinking of many early Marxists. However, faced with the need to accelerate social change through class struggle rather than waiting for the full flowering of capitalism, Marxists such as Li Dazhao began focusing less on materialism or determinism and more on voluntarism. There also arose a doctrine, based on the ideas of Lenin and Trotsky, that right-minded people could ‘telescope’ the phases of the revolution and hasten the transition through the historical stages. This ultimately led to the doctrine of permanent revolution. First promulgated in China in the late 1920s, it reappeared in the 1950s. After Mao’s death, the ‘subjectivity’ movement within Chinese Marxism sought to move the focus away from classes or groups and onto the individual subject as an active agent. Throughout the evolution of Chinese Marxism, political struggles played a direct role in the formulation and discussion of philosophical positions. Mao’s epistemological essay ‘Shijianlun’ clearly reflects the experience of leaders during the guerrilla period, and his theories of knowledge are analogous to the ‘democracy’ practised by the guerrilla leaders: the people were consulted for their knowledge and opinions, decisions were then made from the centre, and the resulting policies were taken back to the masses through teaching. In the same way, Mao believed, individuals perceive through their senses, form theories in their brains (the centre), and test the resulting theories in a manner analogous to teaching. In China, right minds among the people were thought to arise through officials teaching the people. Here pre-modern Confucian legacy becomes important. It helps to explain the endurance of teaching as an official function in the Chinese Marxist discussion of democratic centralism. In Confucianism, the primary function of government was education, although it certainly had other tasks, such as the collection of taxes. All officials, including the emperor, had the task of transforming the character of the people. The education in which the state involved itself, through control of the curriculum and national examinations for the civil service, was moral education. The ultimate aim of state-controlled Confucian education was a one-minded, hierarchical society, meaning that people of all different strata would think the same on important matters. Maoists also sought to create a one-minded people through officially controlled teaching. If the focus of teaching is on right ideas, which are supposed to motivate people towards socialism, one such idea in later Maoist writing is egalitarianism of social status. This was challenged by others, notably Liu Shaoqi, and following Deng Xiaoping’s assumption of power in 1978 it suffered a further blow with the switch in economic policy from central planning to market forces. An example of the relevance of political struggle to the formulation of ideas was the heightening of the campaign against the philosophy called ‘humanism’, following a dispute in 1957 between Mao and President Liu Shaoqi. Liu made a speech in April of that year saying that capitalists had changed and so class struggle against them could be minimized; this was followed by a Maoist-inspired attack on humanism as a philosophy. The humanism that the Maoists attacked was a Confucian-inspired belief in a class-transcending humaneness or compassion for humankind or humaneness. In contrast, in the post-Mao years, the content of humanism has altered, and the term has come to refer to a doctrine inspired by both the early Marx and by the Western psychologist Maslow, namely that the goal of society is the individual’s self-realization. This form of humanism is one of several competing positions that claim to carry on the Marxist tradition in new directions, and has been reinforced by one form of the subjectivity movement in the Deng Xiaoping era.


Author(s):  
Dennis Wood

Benjamin Constant combined the activities of a religious historian, autobiographer and novelist with a career as a political theorist and politician. Constant’s intellectual outlook was shaped by French Enlightenment thought and two years spent at Edinburgh University in 1783–5 added experience of observing the British government and constitution at work. Through all of Constant’s writings runs a consistent theme: the necessity of safeguarding the freedom of the individual in modern society. At the end of his life he summed up his liberalism thus: ‘Freedom in all things, in religion, philosophy, literature, industry and politics. And by freedom I mean the triumph of the individual both over an authority that would wish to govern by despotic means and over the masses who would claim the right to make a minority subservient to a majority’ (1957: 835). Constant’s political activity and his writings, which some consider prophetic of the growth of modern totalitarian regimes, have been influential in the development of liberal thought in Europe and the USA.


1985 ◽  
Vol 1 (3) ◽  
pp. 255-257
Author(s):  
L. Koslowski

Eugene Ionesco once remarked that an excess of politics and an exaggeration of sports are characteristics of our contemporary civilization. The excess of politization affects all parts of our public life, including medicine and its specialty Disaster Medicine. Political ideologies try to usurp a field that has solely humanitarian objectives, that depends on providing for and applying relief to many people in acute distress. There are already many relief organizations and ambulance services, physician staffed emergency medical services systems and first aid trained laymen. There are state and federal disaster relief authorities. Why then was it necessary to add another organization to this sometimes confusing manifold, the German Society on Disaster Medicine?Emergency medicine is for the individual. It must provide optimal care for each single injured or sick person — except for the shortterm management of multiple casualties. Emergency medical missions are limited by time and locality. These missions are hospital services extended to the scene of the accident and work in connection with hospitals. Disaster medicine is for the masses. Its task is to do the best possible for the largest number of people at the right time and at the right place. This implies that in a disaster situation, optimal care for every single individual can and should not be the goal, but rather the best possible care for the largest number. Disaster medicine has to work in large areas, supraregional and long-term. It needs numerous treatment facilities and several steps or levels of treatment. Therefore it requires a firm medical coordination of lay help, primary professional help, transportation, and specialized hospital treatment with maximal efficiency.


2013 ◽  
Vol 9 (S297) ◽  
pp. 58-63
Author(s):  
N. H. Bhatt ◽  
J. Cami

AbstractWe present a comprehensive and sensitive unbiased survey of interstellar features in the near-UV range (3040-3700 Å). We combined a large number of VLT/UVES archival observations of a sample of highly reddened early type stars – typical diffuse interstellar band (DIB) targets. We stacked the individual observations to obtain a spectrum with a signal-to-noise ratio exceeding 1500. Careful inspection of this spectrum reveals tens of absorption features of interstellar nature, most of which can be identified with various atomic and molecular features. We furthermore detect four weak unidentified features, but we cannot establish their interstellar nature. Our sensitivity is limited by telluric and instrumental residuals; this precludes us from detecting broader features (e.g. DIBs). For each detected feature, we measured fundamental parameters (radial velocities, line widths, and equivalent widths). We also compare our co-added spectrum to cold gas-phase laboratory measurements of small, neutral polycyclic aromatic hydrocarbon (PAH) molecules.


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