scholarly journals Kepler mission highlights

2010 ◽  
Vol 6 (S276) ◽  
pp. 34-43 ◽  
Author(s):  
William J. Borucki ◽  
David G. Koch ◽  
Keyword(s):  
Binary Stars ◽  
Variable Stars ◽  
Habitable Zone ◽  
Data Set ◽  
Eclipsing Binary Stars ◽  
The Earth ◽  
Kepler Mission ◽  
Period Orbit ◽  
Short Period ◽  
Data Release

AbstractDuring the first 33.5 days of science-mode operation of the Kepler Mission, the stellar flux of 156,000 stars were observed continuously. The data show the presence of more than 1800 eclipsing binary stars, over 700 stars with planetary candidates, and variable stars of amazing variety. Analyses of the commissioning data also show transits, occultations and light emitted from the known exoplanet HAT-P7b. The depth of the occultation is similar in amplitude to that expected from a transiting Earth-size planet and demonstrates that the Mission has the precision necessary to detect such planets. On 15 June 2010, the Kepler Mission released most of the data from the first quarter of observations. At the time of this data release, 706 stars from this first data set have exoplanet candidates with sizes from as small as that of the Earth to larger than that of Jupiter. More than half the candidates on the released list have radii less than half that of Jupiter. Five candidates are present in and near the habitable zone; two near super-Earth size, one similar in size to Neptune, and two bracketing the size of Jupiter. The released data also include five possible multi-planet systems. One of these has two Neptune-size (2.3 and 2.5 Earth-radius) candidates with near-resonant periods as well as a super-Earth-size planet in a very short period orbit.

scholarly journals SuperWASP variable stars: classifying light curves using citizen science

2021 ◽  
Vol 502 (1) ◽  
pp. 1299-1311
Author(s):  
Heidi B Thiemann ◽  
Andrew J Norton ◽  
Hugh J Dickinson ◽  
Adam McMaster ◽  
Ulrich C Kolb
Keyword(s):  
Variable Stars ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Data Set ◽  
Resultant Data ◽  
Sky Survey ◽  
Short Period ◽  
Contact Binaries ◽  
Analysis Of Results

ABSTRACT We present the first analysis of results from the SuperWASP variable stars Zooniverse project, which is aiming to classify 1.6 million phase-folded light curves of candidate stellar variables observed by the SuperWASP all sky survey with periods detected in the SuperWASP periodicity catalogue. The resultant data set currently contains >1 million classifications corresponding to >500 000 object–period combinations, provided by citizen–scientist volunteers. Volunteer-classified light curves have ∼89 per cent accuracy for detached and semidetached eclipsing binaries, but only ∼9 per cent accuracy for rotationally modulated variables, based on known objects. We demonstrate that this Zooniverse project will be valuable for both population studies of individual variable types and the identification of stellar variables for follow-up. We present preliminary findings on various unique and extreme variables in this analysis, including long-period contact binaries and binaries near the short-period cut-off, and we identify 301 previously unknown binaries and pulsators. We are now in the process of developing a web portal to enable other researchers to access the outputs of the SuperWASP variable stars project.

scholarly journals Discovery of β Cep pulsations in the eclipsing binary V453 Cygni

2020 ◽  
Vol 497 (1) ◽  
pp. L19-L23 ◽  
Author(s):  
John Southworth ◽  
D M Bowman ◽  
A Tkachenko ◽  
K Pavlovski
Keyword(s):  
Physical Properties ◽  
Satellite Data ◽  
Binary Stars ◽  
Mass Measurement ◽  
Physical Processes ◽  
Primary Star ◽  
Eclipsing Binary ◽  
Period Orbit ◽  
Orbital Frequency ◽  
Short Period

ABSTRACT V453 Cyg is an eclipsing binary containing 14 and 11 $\, {\rm M}_\odot$ stars in an eccentric short-period orbit. We have discovered β Cep-type pulsations in this system using Transiting Exoplanet Survey Satellite data. We identify seven significant pulsation frequencies, between 2.37 and 10.51 d−1, in the primary star. These include six frequencies that are separated by yet significantly offset from harmonics of the orbital frequency, indicating they are tidally perturbed modes. We have determined the physical properties of the system to high precision: V453 Cyg A is the first β Cep pulsator with a precise mass measurement. The system is a vital tracer of the physical processes that govern the evolution of massive single and binary stars.

scholarly journals A stellar census in globular clusters with MUSE: A spectral catalogue of emission-line sources

2019 ◽  
Vol 631 ◽  
pp. A118 ◽  
Author(s):  
Fabian Göttgens ◽  
Tim-Oliver Husser ◽  
Sebastian Kamann ◽  
Stefan Dreizler ◽  
Benjamin Giesers ◽  
...  
Keyword(s):  
Emission Line ◽  
Binary Stars ◽  
Globular Clusters ◽  
Cataclysmic Variables ◽  
Variable Stars ◽  
Emission Lines ◽  
Data Set ◽  
Stellar Spectra ◽  
X Ray ◽  
Emission Line Galaxies

Aims. Globular clusters produce many exotic stars due to a much higher frequency of dynamical interactions in their dense stellar environments. Some of these objects were observed together with several hundred thousand other stars in our MUSE survey of 26 Galactic globular clusters. Assuming that at least a few exotic stars have exotic spectra (i.e. spectra that contain emission lines), we can use this large spectroscopic data set of over a million stellar spectra as a blind survey to detect stellar exotica in globular clusters. Methods. To detect emission lines in each spectrum, we modelled the expected shape of an emission line as a Gaussian curve. This template was used for matched filtering on the differences between each observed 1D spectrum and its fitted spectral model. The spectra with the most significant detections of Hα emission are checked visually and cross-matched with published catalogues. Results. We find 156 stars with Hα emission, including several known cataclysmic variables (CV) and two new CVs, pulsating variable stars, eclipsing binary stars, the optical counterpart of a known black hole, several probable sub-subgiants and red stragglers, and 21 background emission-line galaxies. We find possible optical counterparts to 39 X-ray sources, as we detected Hα emission in several spectra of stars that are close to known positions of Chandra X-ray sources. This spectral catalogue can be used to supplement existing or future X-ray or radio observations with spectra of potential optical counterparts to classify the sources.

scholarly journals The Amateur and Eclipsing Binary Stars

1988 ◽  
Vol 98 ◽  
pp. 35-39 ◽  
Author(s):  
Frank Bradshaw Wood
Keyword(s):  
Binary Stars ◽  
Variable Stars ◽  
Eclipsing Binary ◽  
Astronomical Observations ◽  
Minimum Light ◽  
Eclipsing Binary Stars ◽  
Made In

Probably no other branch of science has benefited as much from the work of dedicated amateurs as has the science of Astronomy. While some amateurs have made many useful types of astronomical observations– comets, meteors, occultations, etc. – perhaps none has been as extensive and as useful as those made in the field of variable stars. There are not nearly enough professional astronomers to keep under proper observation the increasingly large number of known variables. While all kinds of them are well worth continuous study, this paper will call attention to the importance of eclipsing variables and in particular the systematic and continuing observation of their times of minimum light.

scholarly journals Roberts of Lovedale and Eclipsing Binary Stars

1988 ◽  
Vol 98 ◽  
pp. 48-49
Author(s):  
Thomas R. Williams
Keyword(s):  
South Africa ◽  
Binary Stars ◽  
Variable Stars ◽  
Apparent Brightness ◽  
Eclipsing Binary ◽  
Systematic Survey ◽  
Eclipsing Binary Stars ◽  
Mathematical Astronomy

Alexander William Roberts, a great humanitarian and teacher in South Africa, was also a luminary in the astronomical world. This paper discusses his work on variable stars and touches briefly on his career in other areas. Born and educated in Scotland, Roberts migrated to South Africa in 1883, at age 25, to teach at the Native College at Lovedale. He studied mathematical astronomy as a recreational pursuit, but became an active observer in 1889. After two years of general observing, be began a systematic survey using binoculars and an old one-inch theodolite. He carefully plotted all visible stars in selected areas and ranked them in order of their apparent brightness, doing so repeatedly on six evenings for each of the selected areas. His composite sketch became a reference chart as he searched for changes in these fields. With this technique, Roberts discovered more than 20 variable stars.

scholarly journals Advances in Modeling Eclipsing Binary Stars in the Era of Large All-Sky Surveys with EBAI and PHOEBE

2011 ◽  
Vol 7 (S282) ◽  
pp. 271-278 ◽  
Author(s):  
A. Prša ◽  
E. F. Guinan ◽  
E. J. Devinney ◽  
P. Degroote ◽  
S. Bloemen ◽  
...  
Keyword(s):  
Binary Stars ◽  
Binary Star ◽  
Lessons Learned ◽  
Eclipsing Binaries ◽  
Eclipsing Binary ◽  
Fundamental Properties ◽  
Eclipsing Binary Stars ◽  
Kepler Mission ◽  
Theoretical Predictions ◽  
Eclipsing Binary Star

AbstractWith the launch of NASA's Kepler mission, stellar astrophysics in general, and the eclipsing binary star field in particular, has witnessed a surge in data quality, interpretation possibilities, and the ability to confront theoretical predictions with observations. The unprecedented data accuracy and an essentially uninterrupted observing mode of over 2000 eclipsing binaries is revolutionizing the field. Amidst all this excitement, we came to realize that our best models to describe the physical and geometric properties of binaries are not good enough. Systematic errors are evident in a large range of binary light curves, and the residuals are anything but Gaussian. This is crucial because it limits us in the precision of the attained parameters. Since eclipsing binary stars are prime targets for determining the fundamental properties of stars, including their ages and distances, the penalty for this loss of accuracy affects other areas of astrophysics as well. Here, we propose to substantially revamp our current models by applying the lessons learned while reducing, modeling, and analyzing Kepler data.

scholarly journals Photometric analysis of eclipsing binary stars

2019 ◽  
Vol 11 (20) ◽  
pp. 120-126
Author(s):  
Bushra Qassim AL-Abudi
Keyword(s):  
Computer Modeling ◽  
Binary Stars ◽  
Software Package ◽  
Eclipsing Binaries ◽  
Geometric Parameters ◽  
Photometric Analysis ◽  
Eclipsing Binary ◽  
Eclipsing Binary Stars ◽  
Short Period ◽  
Good Agreement

In this paper, photometric analysis of two short period group of the eclipsing binaries (RS CVn); RT And and BH Vir is presented. New physical and geometric parameters were obtained by performing two computer modeling. The first model is software package PHOEBE based on the Wilson–Devinney method, and the second is Binary Maker 3 (BM3).Our results are in good agreement with those obtained using the same modeling.

scholarly journals Orbital Elements of MACHO Project Eclipsing Binary Stars

2005 ◽  
Vol 13 ◽  
pp. 467-467
Author(s):  
Charles Alcock
Keyword(s):  
Binary Stars ◽  
Large Scale ◽  
Major Axis ◽  
Orbital Elements ◽  
Semi Major Axis ◽  
Eclipsing Binary ◽  
Eclipsing Binary Stars ◽  
Large Numbers ◽  
Short Period ◽  
Velocity Information

Large scale photometric surveys can deliver very large numbers of eclipsing binary stars. It is not presently possible to obtain radial velocity information for more than a small fraction of these. We have made some progress in the estimation of the statistical distributions of orbital elements (including semi-major axis and eccentricity) in the MACHO Project catalog of eclipsing binary stars. We see the well-known tendency to circularization in short period orbits and also detect late tidal circularization during the giant phase. The extension of these techniques to newer surveys will also be discussed.

scholarly journals The hazard from fragmenting comets

2019 ◽  
Author(s):  
W M Napier
Keyword(s):  
Cross Sectional Area ◽  
Large Animal ◽  
Sectional Area ◽  
Multiple Impacts ◽  
Cross Sectional ◽  
The Earth ◽  
Period Orbit ◽  
Short Period ◽  
The Cross ◽  
Climatic Cooling

Abstract Comet disintegration proceeds both through sublimation and discrete splitting events. The cross-sectional area of material ejected by a comet may, within days, become many times greater than that of the Earth, making encounters with such debris much more likely than collisions with the nucleus itself. The hierarchic fragmentation and sublimation of a large comet in a short period orbit may yield many hundreds of such short-lived clusters. We model this evolution with a view to assessing the probability of an encounter which might have significant terrestrial effects, through atmospheric dusting or multiple impacts. Such an encounter may have contributed to the large animal extinctions and sudden climatic cooling of 12,900 years ago, and the near-simultaneous collapse of civilisations around 2350 BC.

scholarly journals Variable stars in the field of intermediate-age open cluster NGC 559

2020 ◽  
Vol 499 (1) ◽  
pp. 618-630
Author(s):  
Y C Joshi ◽  
Ancy A John ◽  
J Maurya ◽  
A Panchal ◽  
Brijesh Kumar ◽  
...  
Keyword(s):  
Binary Stars ◽  
Binary Systems ◽  
Open Cluster ◽  
Variable Stars ◽  
Photometric Variability ◽  
Eclipsing Binary ◽  
V Band ◽  
Target Field ◽  
Periodicity Analysis ◽  
Short Period

ABSTRACT This work presents the first long-term photometric variability survey of the intermediate-age open cluster NGC 559. Time series V-band photometric observations on 40 nights taken over more than 3 yr with three different telescopes are analysed to search for variable stars in the cluster. We investigate the data for the periodicity analysis and reveal 70 variable stars including 67 periodic variables in the target field, all of them are newly discovered. The membership analysis of the periodic variables reveals that 30 of them belong to the cluster and remaining 37 are identified as field variables. Out of the 67 periodic variables, 48 are short-period (P < 1 d) variables and 19 are long-period (P > 1 d) variables. The variable stars have periodicity between 3 h to 41 d and their brightness ranges from V  = 10.9 to 19.3 mag. The periodic variables belonging to the cluster are then classified into different variability types on the basis of observational properties such as shape of the light curves, periods, amplitudes, as well as their positions in the Hertzsprung–Russell (H–R) diagram. As a result, we identify 1 Algol type eclipsing binary, 1 possible blue straggler star, 3 slowly pulsating B type stars, 5 rotational variables, 11 non-pulsating variables, 2 FKCOM variables, and remaining 7 are characterized as miscellaneous variables. We also identify three eclipsing binary stars (EBs) belonging to the field star population. The phoebe package is used to analyse the light curve of all four EBs in order to determine the parameters of the binary systems such as masses, temperatures, and radii.

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