scholarly journals Multiband light-curve analysis of the 40.5-min period eclipsing double-degenerate binary SDSS J082239.54+304857.19

2020 ◽  
Vol 500 (4) ◽  
pp. 5098-5105
Author(s):  
Alekzander Kosakowski ◽  
Mukremin Kilic ◽  
Warren Brown
Keyword(s):  
Light Curve ◽  
Gravitational Waves ◽  
High Speed ◽  
Broad Band ◽  
Light Curve Analysis ◽  
Expected Time ◽  
Secondary Star ◽  
Orbital Decay ◽  
Best Fitting ◽  
Low Mass

ABSTRACT We present the Apache Point Observatory BG40 broad-band and simultaneous Gemini r-band and i-band high-speed follow-up photometry observations and analysis of the 40.5-min period eclipsing detached double-degenerate binary SDSS J082239.54+304857.19. Our APO data spans over 318 d and includes 13 primary eclipses, from which we precisely measure the system’s orbital period and improve the time of mid-eclipse measurement. We fit the light curves for each filter individually and show that this system contains a low-mass DA white dwarf with radius RA = 0.031 ± 0.006 R⊙ and a RB = 0.013 ± 0.005 R⊙ companion at an inclination of i = 87.7 ± 0.2○. We use the best-fitting eclipsing light curve model to estimate the temperature of the secondary star as Teff = 5200 ± 100 K. Finally, while we do not record significant offsets to the expected time of mid-eclipse caused by the emission of gravitational waves with our 1-yr baseline, we show that a 3σ significant measurement of the orbital decay due to gravitational waves will be possible in 2023, at which point the eclipse will occur about 8  s earlier than expected.

scholarly journals The Eclipses of the Close Binary Star BE UMa

1996 ◽  
Vol 158 ◽  
pp. 471-472
Author(s):  
Janet H. Wood ◽  
E. L. Robinson ◽  
E.-H. Zhang
Keyword(s):  
Light Curve ◽  
High Speed ◽  
Binary Star ◽  
Light Curves ◽  
Close Binary ◽  
Primary Star ◽  
Secondary Star ◽  
Different Depths ◽  
The Mean ◽  
Close Binary Star

BE UMa is a close binary star, not transferring mass, with an extremely hot primary star irradiating the inner face of the cool secondary star. The light curve shows a large-amplitude, sinusoidal variation with a period of 2.29 d, and an eclipse that is centered on the minimum of the variation [1], [3]. According to [1], the eclipse is partial, not total. However, it has been argued [2] that the eclipse was really flat bottomed and thus total. This has important repercussions for the deduced model of the system. To resolve this issue we obtained simultaneous UBVR photometry of BE UMa using the Stiening 4-channel, high-speed photometer on the 82-inch telescope at McDonald Observatory. The mean light curves are shown in Fig. 1. The eclipse in all colours is round bottomed and partial. The different depths are caused by the different contribution from the red secondary star in each bandpass.

scholarly journals Broad-band spectral energy distribution of the X-ray transient Swift J1745−26 from outburst to quiescence

2020 ◽  
Vol 637 ◽  
pp. A2
Author(s):  
Sylvain Chaty ◽  
Francis Fortin ◽  
Alicia López-Oramas
Keyword(s):  
Energy Distribution ◽  
Light Curve ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
Spectral Energy ◽  
X Ray ◽  
Upper Limit ◽  
Spectral Break ◽  
Hard State ◽  
Low Mass

Aims. We aim to analyse our study of the X-ray transient Swift J1745−26, using observations obtained from its outburst in September 2012, up to its decay towards quiescence in March 2013. Methods. We obtained optical and infrared observations, through override programme at ESO/VLT with FORS2 and ISAAC instruments, and added archival optical (VLT/VIRCAM), radio and X-ray (Swift) observations, to build the light curve and the broad-band spectral energy distribution (SED) of Swift J1745−26. Results. We show that, during its outburst and also during its decay towards quiescence, Swift J1745−26 SED can be adjusted, from infrared up to X-rays, by the sum of both a viscous irradiated multi-colour black body emitted by an accretion disc, and a synchrotron power law at high energy. In the radio domain, the SED arises from synchrotron emission from the jet. While our SED fitting confirms that the source remained in the low/hard state during its outburst, we determine an X-ray spectral break at frequency 3.1 ≤ νbreak ≤ 3.4 × 1014 Hz, and a radio spectral break at 1012 Hz ≤ νbreak ≤ 1013 Hz. We also show that the system is compatible with an absorption AV of ∼7.69 mag, lies within a distance interval of D ∼ [2.6 − 4.8] kpc with an upper limit of orbital period Porb = 11.3 h, and that the companion star is a late spectral type in the range K0–M0 V, confirming that the system is a low-mass X-ray binary. We finally plot the position of Swift J1745−26 on an optical-infrared – X-ray luminosity diagram: its localisation on this diagram is consistent with the source staying in the low-hard state during outburst and decay phases. Conclusions. By using new observations obtained at ESO/VLT with FORS2 and ISAAC, and adding archival optical (VLT/VIRCAM), radio and X-ray (Swift) observations, we built the light curve and the broad-band SED of Swift J1745−26, and we plotted its position on an optical-infrared – X-ray luminosity diagram. By fitting the SED, we characterized the emission of the source from infrared, via optical, up to X-ray domain, we determined the position of both the radio and X-ray spectral breaks, we confirmed that it remained in the low-hard state during outburst and decay phases, and we derived its absorption, distance interval, orbital period upper limit, and the late-type nature of companion star, confirming Swift J1745−26 is a low-mass X-ray binary.

scholarly journals Synthetic Light-Curve Analysis of a Short Period Binary System YY Eri

2021 ◽  
Vol 58 (1) ◽  
pp. 5454-5456
Author(s):  
Warisa Pancharoen, Wiraporn Maithong
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Effective Temperature ◽  
Curve Analysis ◽  
Photometric System ◽  
Mass Ratio ◽  
Light Curve Analysis ◽  
The Public ◽  
Secondary Star ◽  
Short Period

YY Eri, the short-period binary system, is a W UMa type of the eclipsing binary system. This study using a 0.7-meter telescope with CCD photometric system in B V and R filters. It was observed at the Regional Observatory for the Public, Chachoengsao, Thailand on December 5, 2018, UT. The MaxIm DL software was used to analyzed the images photometry to produce the light curve. The Wilson-Devinney technique was computed the synthetic light curve that prefer to the physical properties of the YY Eri. The results show that the effective temperature of the primary and secondary star was 5533 and 5598 K, respectively. The inclination is 81.450 and the mass ratio is 0.55. The degree of contact was calculated as 16.64%  

scholarly journals Light curve analysis of the eclipsing binary system V781 Tau

2021 ◽  
Vol 2145 (1) ◽  
pp. 012005
Author(s):  
N Lamlert ◽  
W Maithong
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Orbital Period ◽  
Binary Systems ◽  
Curve Analysis ◽  
Photometric System ◽  
Light Curve Analysis ◽  
Eclipsing Binary ◽  
The Public ◽  
Secondary Star

Abstract V781 Tau is one of W UMa eclipsing binary systems whose orbital period is 0.34 days. The 0.7-meter telescope with CCD photometric system in B and V filters was conducted at the Regional Observatory for the Public, Chachoengsao, Thailand during December 2018, UT. The Wilson-Devinney Technique was used for calculating the physical properties of V781 Tau. The results showed the inclination of their orbital is 66.140°±0.14. The effective temperature of the primary and secondary star is 6,060 and 5,881 K, respectively and the degree of contact is 4.38 %

scholarly journals High-Level Magnetic Activity on a Low-Mass Close Binary: GSC 02038-0293

2012 ◽  
Vol 29 (2) ◽  
pp. 150-160 ◽  
Author(s):  
H. A. Dal ◽  
E. Sipahi ◽  
O. Özdarcan
Keyword(s):  
Light Curve ◽  
Active Component ◽  
Magnetic Activity ◽  
Curve Analysis ◽  
Light Curves ◽  
Close Binary ◽  
Physical Parameters ◽  
Light Curve Analysis ◽  
Low Mass ◽  
High Level

AbstractTaking into account results obtained from light-curve analysis and out-of-eclipse analyses, we discuss the nature of GSC 02038-00293 and also its magnetic activity behaviour.We obtained light curves of the system during observing seasons 2007, 2008 and 2011. We obtained its secondary minimum clearly in I-band observations in 2008 for the first time. Analysing this light curve, we found the physical parameters of the components. The light-curve analysis indicates that the possible mass ratio of the system is 0.35. We obtained the remaining V-band light curves, extracting the eclipses. We modelled these remaining curves using the SPOTMODEL program and found possible spot configurations of the magnetically active component for each observing season. The models demonstrated that there are two active longitudes for the active component. The models reveal that both active longitudes migrate in the direction of decreasing longitude. We also examined the light curves in out-of-eclipse phases with respect to minimum and maximum brightness, amplitude, etc. The amplitude of the curves during out-of-eclipse phases varies in a sinusoidal way with a period of ∼8.9 yr; the mean brightness of the system is dramatically decreasing. The phases of the deeper minimum during out-of-eclipse periods exhibit a migration toward decreasing phase.

scholarly journals An extreme-mass ratio, short-period eclipsing binary consisting of a B dwarf primary and a pre-main-sequence M star companion discovered by KELT

2020 ◽  
Vol 499 (3) ◽  
pp. 3775-3791
Author(s):  
Daniel J Stevens ◽  
George Zhou ◽  
Marshall C Johnson ◽  
Aaron C Rizzuto ◽  
Joseph E Rodriguez ◽  
...  
Keyword(s):  
Light Curve ◽  
Global Analysis ◽  
Binary Star ◽  
Spectral Energy Distribution ◽  
Broad Band ◽  
Phase Curve ◽  
Mass Ratio ◽  
Eclipsing Binary ◽  
Short Period ◽  
Low Mass

ABSTRACT We present the discovery of KELT J072709 + 072007 (HD 58730), a very low mass ratio (q ≡ M2/M1 ≈ 0.07) eclipsing binary (EB) identified by the Kilodegree Extremely Little Telescope (KELT) survey. We present the discovery light curve and perform a global analysis of four high-precision ground-based light curves, the Transiting Exoplanets Survey Satellite (TESS) light curve, radial velocity (RV) measurements, Doppler Tomography (DT) measurements, and the broad-band spectral energy distribution. Results from the global analysis are consistent with a fully convective ($M_2 = 0.22 \pm 0.02\ \, \mathrm{M}_{\odot })$ M star transiting a late-B primary ($M_1 = 3.34^{+0.07}_{-0.09}\ \, \mathrm{M}_{\odot }\,\mathrm{ and}\,\ T_{\rm eff,1} = 11960^{+430}_{-520}\ {\rm K}$). We infer that the primary star is $183_{-30}^{+33}$ Myr old and that the companion star’s radius is inflated by $26 \pm 8{{\ \rm per\ cent}}$ relative to the predicted value from a low-mass isochrone of similar age. We separately and analytically fit for the variability in the out-of-eclipse TESS phase curve, finding good agreement between the resulting stellar parameters and those from the global fit. Such systems are valuable for testing theories of binary star formation and understanding how the environment of a star in a close-but-detached binary affects its physical properties. In particular, we examine how a star’s properties in such a binary might differ from the properties it would have in isolation.

Bleed Slot Benefits on Turbocharger Centrifugal Compressor Stability

2014 ◽  
Author(s):  
Matthieu Gancedo ◽  
Erwann Guillou ◽  
Ephraim Gutmark
Keyword(s):  
Mass Flow ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Broad Band ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Low Mass ◽  
Response Pressure ◽  
Compressor Map ◽  
Speed Response

Bleed slots located in the inducer region of centrifugal compressors have been demonstrated to extend the surge margin with minimal negative impact on performance. This paper describes the investigation of the effect of a bleed slot on map width enhancement of a turbocharger centrifugal compressor used for heavy duty diesel engine application. The goal is to evaluate the overall pressure instabilities on the compressor map and to study the dynamic phenomena occurring at low mass flow rates to better understand the benefits of the bleed slot on the compressor stability and surge line. The obstruction of the bleed slot permitted to compare the compressor behavior with the recirculation feature and without it. The pressure instability levels were measured along the accessible compressor map for the two cases using a high speed response pressure transducer at the compressor outlet. In addition, static and dynamic pressure measurements were conducted within the diffuser using respectively pressure taps and high speed response pressure transducers. The compressor with open bleed slot proved to have lower instability levels at low mass flow rates when not experiencing deep surge. Frequency responses at low mass flow rates showed that the implementation of the bleed slot suppresses broad band frequencies below the rpm frequency, which improves the overall stability. These frequencies are associated with rotating instabilities (RIs) with changing propagation speed depending on the rotational speed. At lower speeds, RIs are propagated with the wheel rotation whereas at higher speeds, they tend to propagate with the speed associated with their characteristic frequency.

scholarly journals X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Trianguli

2018 ◽  
Vol 619 ◽  
pp. A138
Author(s):  
V. Perdelwitz ◽  
S. Czesla ◽  
J. Robrade ◽  
T. Pribulla ◽  
J. H. M. M. Schmitt
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Binary Systems ◽  
Uv Light ◽  
Close Binary ◽  
Eclipsing Binary ◽  
X Ray ◽  
Uv Emission ◽  
Low Mass ◽  
Orbital Modulation

Context.Close binary systems provide an excellent tool for determining stellar parameters such as radii and masses with a high degree of precision. Due to the high rotational velocities, most of these systems exhibit strong signs of magnetic activity, postulated to be the underlying reason for radius inflation in many of the components. Aims.We extend the sample of low-mass binary systems with well-known X-ray properties. Methods.We analyze data from a singular XMM-Newton pointing of the close, low-mass eclipsing binary system BX Tri. The UV light curve was modeled with the eclipsing binary modeling tool PHOEBE and data acquired with the EPIC cameras was analyzed to search for hints of orbital modulation. Results.We find clear evidence of orbital modulation in the UV light curve and show that PHOEBE is fully capable of modeling data within this wavelength range. Comparison to a theoretical flux prediction based on PHOENIX models shows that the majority of UV emission is of photospheric origin. While the X-ray light curve does exhibit strong variations, the signal-to-noise ratio of the observation is insufficient for a clear detection of signs of orbital modulation. There is evidence of a Neupert-like correlation between UV and X-ray data.

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