scholarly journals A survey for high-mass eclipsing binaries

2019 ◽  
Vol 490 (4) ◽  
pp. 5147-5173
Author(s):  
F Pozo Nuñez ◽  
R Chini ◽  
A Barr Domínguez ◽  
Ch Fein ◽  
M Hackstein ◽  
...  
Keyword(s):  
Eclipsing Binaries ◽  
Light Curves ◽  
High Mass ◽  
System Component ◽  
Fundamental Parameters ◽  
Average Value ◽  
Short Period ◽  
Orbital Periods ◽  
Photometric Monitoring ◽  
Period System

ABSTRACT We report results from a search for Galactic high-mass eclipsing binaries. The photometric monitoring campaign was performed in Sloan r and i with the robotic twin refractor RoBoTT at the Universitätssternwarte Bochum in Chile and complemented by Johnson UBV data. Comparison with the SIMBAD data base reveals 260 variable high-mass stars. Based on well-sampled light curves, we discovered 35 new eclipsing high-mass systems and confirm the properties of six previously known systems. For all objects, we provide the first light curves and determine orbital periods through the Lafler–Kinman algorithm. Apart from GSC 08173-0018 and Pismis 24-13 ($P = 19.47\, d$ and $20.14\, d$) and the exceptional short-period system TYC 6561-1765-1 ($P = 0.71\, d$), all systems have orbital periods between 1 and 9 d. We model the light curves of 26 systems within the framework of the Roche geometry and calculate fundamental parameters for each system component. The Roche lobe analysis indicates that 14 systems have a detached geometry, while 12 systems have a semidetached geometry; seven of them are near-contact systems. The deduced mass ratios q = M2/M1 reach from 0.4 to 1.0 with an average value of 0.8. The similarity of masses suggests that these high-mass binaries were created during the star formation process rather than by tidal capture.

scholarly journals Observations and light curve solutions of the eclipsing binaries USNO-B1.0 1395-0370184 and USNO-B1.0 1395-0370731

2016 ◽  
pp. 27-32 ◽  
Author(s):  
D. Kjurkchieva ◽  
V.A. Popov ◽  
D. Vasileva ◽  
N. Petrov
Keyword(s):  
Light Curve ◽  
Eclipsing Binaries ◽  
Eclipsing Stars ◽  
System P ◽  
Photometric Observations ◽  
Short Period ◽  
Orbital Periods ◽  
Period System

We present follow-up photometric observations in Sloan filters g', i' of the newly discovered eclipsing stars USNO-B1.0 1395-0370184 and USNO-B1.0 1395-0370731. Our data revealed that their orbital periods are considerably bigger than the previous values. This result changed the classification of USNO-B1.0 1395-0370184 from ultrashort-period binary (P=0.197 d) to short-period system (P=0.251 d). The light curve solutions of our observations revealed that USNOB1.0 1395-0370184 and USNO-B1.0 1395-0370731 are overcontact binaries in which components are K dwarfs, close in masses and radii. The light curve distortions were reproduced by cool spots with angular radius of around 20?.

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 High-Mass X-ray Binaries: progenitors of double compact objects

2018 ◽  
Vol 14 (S346) ◽  
pp. 1-13
Author(s):  
Edward P. J. van den Heuvel
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Stars ◽  
Compact Objects ◽  
High Mass ◽  
X Ray ◽  
Future Evolution ◽  
Short Period ◽  
Orbital Periods ◽  
X Ray Binaries

AbstractA summary is given of the present state of our knowledge of High-Mass X-ray Binaries (HMXBs), their formation and expected future evolution. Among the HMXB-systems that contain neutron stars, only those that have orbital periods upwards of one year will survive the Common-Envelope (CE) evolution that follows the HMXB phase. These systems may produce close double neutron stars with eccentric orbits. The HMXBs that contain black holes do not necessarily evolve into a CE phase. Systems with relatively short orbital periods will evolve by stable Roche-lobe overflow to short-period Wolf-Rayet (WR) X-ray binaries containing a black hole. Two other ways for the formation of WR X-ray binaries with black holes are identified: CE-evolution of wide HMXBs and homogeneous evolution of very close systems. In all three cases, the final product of the WR X-ray binary will be a double black hole or a black hole neutron star binary.

A high-mass-ratio red-dwarf contact binary with an extremely cool close-in red dwarf

2019 ◽  
Author(s):  
Xiao-Hui Fang ◽  
Shengbang Qian ◽  
Miloslav Zejda ◽  
Soonthornthum Boonrucksar ◽  
Xiao Zhou ◽  
...  
Keyword(s):  
Orbital Period ◽  
Light Curves ◽  
High Mass ◽  
Mass Ratio ◽  
Third Body ◽  
Dynamical Interaction ◽  
The Third ◽  
Short Period ◽  
Contact Binaries ◽  
Mass Component

Abstract 1SWASP J161335.80$-$284722.2 (hereafter J161335) is an eclipsing red-dwarf binary with an orbital period of $0.229778\:$d, which is around the short-period limit for contact binaries. Three sets of multi-color light curves of J161335 were obtained from different telescopes in 2015 and 2016 and are analyzed using the Wilson–Devinney method. We discovered that the system is a W-type contact system with a contact degree of 19% and a high mass ratio of 0.91. By using all available eclipse times, we found that the observed $-$ calculated $(O-C)$ diagram displays a cyclic oscillation with an amplitude of 0.00196($\pm 0.00006)\:$d and a period of 4.79($\pm 0.14)\:$yr while it undergoes a downward parabolic change. This downward variation corresponds to a continuous decrease in the orbital period at a rate of $dP/dt = -4.26(\pm$0.01) $\times$ 10$^{-7}\:$d$\:$yr$^{-1}$. The small-amplitude oscillation is explained as the light travel-time effect from the gravitational influence of a third body with a lowest mass of $M _{3}$ = 0.15($\pm 0.01)M_{\,\odot }$. In solving the light curves, we found that the third light is increasing, with the wavelength suggesting that the third body may be a cool red dwarf. This is in agreement with the results obtained by analyzing the $O-C$ diagram. The tertiary red dwarf is orbiting the central red-dwarf binary at an orbital separation of 2.8($\pm 0.2$) au. These results suggest that the J161335 system may be formed through early dynamical interaction where the original low-mass component was replaced by a higher-mass third body and the lower-mass component was kicked out to a wider orbit. In this way, a hierarchical triple system similar to J161335 with a high-mass-ratio binary and a small close-in third body is formed.

scholarly journals Imaging stellar coronae from eclipsing binary X-ray light curves

1996 ◽  
Vol 176 ◽  
pp. 469-476 ◽  
Author(s):  
M. Siarkowski
Keyword(s):  
Eclipsing Binaries ◽  
Light Curves ◽  
Late Type ◽  
X Ray ◽  
Spatially Resolved ◽  
Direct Observations ◽  
Tidal Forces ◽  
Orbital Modulation ◽  
Orbital Periods ◽  
Detached Binaries

The Sun is the only star whose X-ray emitting, strongly inhomogenous corona can be spatially resolved via direct observations. For other late type-stars it is known that coronae do exist, but the spatial distribution of their emission is largely unknown. However in the case of eclipsing binaries this spatial structure can be potentially deduced from the orbital modulation of the observed X-ray light curve. The best candidates for this kind of analysis are RS CVn binaries, the most active and luminous late-type X-ray coronal sources. These are detached binaries with periods typically between 0.5 and 20 days, in which one or both stars have evolved into subgiant or giant of spectral type G or K. For short orbital periods (< 14 days) the tidal forces lead to synchronization of the orbital and rotational periods, so these systems rotate rigidly.

scholarly journals A Flare-Like Event from the Short-Period System XY UMa

1983 ◽  
Vol 71 ◽  
pp. 411-413
Author(s):  
M. Zeilik ◽  
R. Elston ◽  
G. Henson ◽  
P. Smith
Keyword(s):  
Light Curve ◽  
Light Curves ◽  
Active System ◽  
Primary Star ◽  
Rs Cvn Stars ◽  
Short Period ◽  
Annual Changes ◽  
Period System ◽  
Photoelectric Observations

XY UMa (+55°1317, SA027143) is a short-period (P 0.48 d) cousin of the RS CVn stars. The primary star is G2-G5V; the secondary K5 (Geyer, quoted by Lorenzi and Scaltriti, 1977). Geyer (1977) has done the bulk of the observational work to date, including the first photoelectric observations. The rapid, annual changes in XY UMa's light curve, and the fact that the last published light curves was from the 1977 season convinced us to reobserve this active system.

scholarly journals Starspot migration in close binaries: A fast parameters evaluation from large sky surveys

2016 ◽  
Vol 12 (S325) ◽  
pp. 274-277
Author(s):  
B. Debski ◽  
S. Zola
Keyword(s):  
Visual Inspection ◽  
Magnetic Activity ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Close Binaries ◽  
Intrinsic Variability ◽  
Sky Surveys ◽  
Orbital Periods

AbstractWe developed a method that allows to classify the light curves of eclipsing binaries of the W UMa type (EW) with respect to their intrinsic variability. The algorithm measures several features of light curves, such as the amplitude of the O’Connell effect, the separation and location of maxima brightness as well as depths of the minima in subsequent orbital periods. This method is capable of distinguishing systems with presumed magnetic activity present from these without it, as well as recognizing systems with starspots migration and those with other types of intrinsic variability manifestation. The classification is done in an automatic way without a time consuming, visual inspection of light curves.

scholarly journals Differential rotation in convective envelopes: constraints from eclipsing binaries

2019 ◽  
Vol 491 (1) ◽  
pp. 690-707 ◽  
Author(s):  
Adam S Jermyn ◽  
Jamie Tayar ◽  
Jim Fuller
Keyword(s):  
Differential Rotation ◽  
Orbital Period ◽  
Binary Systems ◽  
Rotation Period ◽  
Eclipsing Binaries ◽  
Rotation Periods ◽  
Short Period ◽  
Orbital Periods ◽  
The Difference ◽  
Surface Convection

ABSTRACT Over time, tides synchronize the rotation periods of stars in a binary system to the orbital period. However, if the star exhibits differential rotation, then only a portion of it can rotate at the orbital period, so the rotation period at the surface may not match the orbital period. The difference between the rotation and orbital periods can therefore be used to infer the extent of the differential rotation. We use a simple parametrization of differential rotation in stars with convective envelopes in circular orbits to predict the difference between the surface rotation period and the orbital period. Comparing this parametrization to observed eclipsing binary systems, we find that in the surface convection zones of stars in short-period binaries there is very little radial differential rotation, with |r∂rln Ω| &lt; 0.02. This holds even for longer orbital periods, though it is harder to say which systems are synchronized at long periods, and larger differential rotation is degenerate with asynchronous rotation.

scholarly journals Time-Resolved Spectroscopy of Short Period RS CVn Systems

1993 ◽  
Vol 137 ◽  
pp. 392-394
Author(s):  
C. Lázaro ◽  
M.J. Arévalo
Keyword(s):  
Spectral Type ◽  
Main Sequence ◽  
Eclipsing Binaries ◽  
Time Resolved ◽  
Binary Model ◽  
Short Period ◽  
First Results ◽  
Orbital Phase ◽  
Phase Resolution ◽  
Orbital Periods

AbstractWe have initiated a programme of spectroscopic observations of RS CVn short-period group, with orbital phase resolution. The systems of this group are all eclipsing binaries with both components at the Main Sequence, and most of them have similar spectral type components. The high rotational velocities and their short orbital periods (less than 1 day) hinder the spectroscopic study of these stars. We presents the first results yielded by Hα line observations of the systems XY UMa and WY Cnc. Both systems were observed during 1991 with reasonably wide orbital phase coverage. The analysis of the spectra is made by comparison with a binary model, constructed from the observed spectra of normal stars of the same spectral type as the RS CVn system components. The model accounts for the partial contribution of each component at any orbital phase within eclipses.

scholarly journals Systematic search for stellar pulsators in the eclipsing binaries observed by Kepler

2019 ◽  
Vol 630 ◽  
pp. A106 ◽  
Author(s):  
Patrick Gaulme ◽  
Joyce A. Guzik
Keyword(s):  
Stellar Evolution ◽  
Percent Level ◽  
Eclipsing Binaries ◽  
Light Curves ◽  
Systematic Search ◽  
Red Giants ◽  
Low Mass Stars ◽  
Orbital Periods ◽  
Red Giant ◽  
Stellar Properties

Eclipsing binaries (EBs) are unique targets for measuring precise stellar properties and can be used to constrain stellar evolution models. In particular, it is possible to measure masses and radii of both components of a double-lined spectroscopic EB at the percent level. Since the advent of high-precision photometric space missions (MOST, CoRoT, Kepler, BRITE, TESS), the use of stellar pulsation properties to infer stellar interiors and dynamics constitutes a revolution for studies of low-mass stars. The Kepler mission has led to the discovery of thousands of classical pulsators such as δ Scuti and solar-like oscillators (main sequence and evolved), but also almost 3000 EBs with orbital periods shorter than 1100 days. We report the first systematic search for stellar pulsators in the entire Kepler EB catalog. The focus is mainly aimed at discovering δ Scuti, γ Doradus, red giant, and tidally excited pulsators. We developed a data inspection tool (DIT) that automatically produces a series of plots from the Kepler light curves that allows us to visually identify whether stellar oscillations are present in a given time series. We applied the DIT to the whole Kepler EB database and identified 303 systems whose light curves display oscillations, including 163 new discoveries. A total of 149 stars are flagged as δ Scuti (100 from this paper), 115 as γ Doradus (69 new), 85 as red giants (27 new), and 59 as tidally excited oscillators (29 new). There is some overlap among these groups, as some display several types of oscillations. Despite the likelihood that many of these systems are false positives, for example, when an EB light curve is blended with a pulsator, this catalog gathers a vast sample of systems that are valuable for a better understanding of stellar evolution.

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