scholarly journals KIC 4544587: An Eccentric, Short Period Binary with δ Scuti Pulsations and Tidally Excited Modes

2011 ◽  
Vol 7 (S282) ◽  
pp. 77-78
Author(s):  
Kelly Hambleton ◽  
Don Kurtz ◽  
Andrej Prša ◽  
Steven Bloemen ◽  
John Southworth
Keyword(s):  
Light Curve ◽  
Orbital Period ◽  
Main Sequence ◽  
Binary Star ◽  
Original Data ◽  
Primary Component ◽  
Apsidal Motion ◽  
Orbital Frequency ◽  
Short Period ◽  
Eclipsing Binary Star

AbstractKIC 4544587 is an eclipsing binary star with clear signs of apsidal motion and indications of tidal resonance. The primary component is an early A-type δ Scuti variable, with a temperature of 8270±250 K, whilst the secondary component is an early G-type main sequence star with a temperature of 6500±310 K. The orbital period of this system is 2.18911(1) d, with the light curve demonstrating a hump after secondary minimum due to distortion and reflection. The frequency spectrum of the residual data (the original data with the binary characteristics removed) contains both pressure (p) and gravity (g) modes. Eight of the g modes are precise multiples of the orbital frequency, to an accuracy greater than 3 σ. This is a signature of resonant excitation.

scholarly journals Activity and Secondary Minimum of RZ Eridani

1989 ◽  
Vol 107 ◽  
pp. 351-351
Author(s):  
Z. Kviz
Keyword(s):  
Light Curve ◽  
Binary Star ◽  
Active Regions ◽  
Primary Component ◽  
Secondary Minimum ◽  
Photometric System ◽  
Gas Streams ◽  
Rs Cvn Stars ◽  
Eclipsing Binary Star ◽  
Short Time

RZ Eridani is an eclipsing binary star with Algol-type light curve of rather long period of 39.28 days. As this star exhibits emission lines of Ca 11 H and K it was classified also as RS CVn type. RZ Eri has been occasionally observed with the GENEVA photometric system with 40cm and later 70cm Swiss telescope at La Silla, Chile, since 1977 mainly for obtaining a complete light curve and for detecting the secondary minimum. The observation showed, that the brightness outside minima really varies as the RS CVn stars usually do. The secondary minimum has been detected at the phase 0.67. Apart from that, the variation of the brightness outside the minima occasionally drops for a short time (about one day or even less). These drops may be due to rotation and uneven distribution of active regions on the surface of the secondary or by the gas streams between the two components. The variation of the light outside minima is certainly not caused by the primary component, because such jumps in the brightness were detected during the total eclipse, when the primary component is not visible. This star certainly deserves more both photometric and spectroscopic attention. Preliminary search for periodicities by G. Burki showed that apart from the orbital period no other periods within the range of days are present. Further details will be published later elsewhere.

The Eclipsing Binary WX Eridani

1979 ◽  
Vol 46 ◽  
pp. 385
Author(s):  
M.B.K. Sarma ◽  
K.D. Abhankar
Keyword(s):  
Light Curve ◽  
Spectral Type ◽  
Orbital Period ◽  
Primary Component ◽  
Light Curves ◽  
Absorption Feature ◽  
Primary Star ◽  
Eclipsing Binary ◽  
The Times ◽  
Phase Angles

AbstractThe Algol-type eclipsing binary WX Eridani was observed on 21 nights on the 48-inch telescope of the Japal-Rangapur Observatory during 1973-75 in B and V colours. An improved period of P = 0.82327038 days was obtained from the analysis of the times of five primary minima. An absorption feature between phase angles 50-80, 100-130, 230-260 and 280-310 was present in the light curves. The analysis of the light curves indicated the eclipses to be grazing with primary to be transit and secondary, an occultation. Elements derived from the solution of the light curve using Russel-Merrill method are given. From comparison of the fractional radii with Roche lobes, it is concluded that none of the components have filled their respective lobes but the primary star seems to be evolving. The spectral type of the primary component was estimated to be F3 and is found to be pulsating with two periods equal to one-fifth and one-sixth of the orbital period.

scholarly journals V392 Orionis: Observations and Evolutionary State of a Low-Mass System

1998 ◽  
Vol 11 (1) ◽  
pp. 371-371
Author(s):  
S. Narusawa ◽  
A. Yamasaki ◽  
Y. Nakamura
Keyword(s):  
Binary Systems ◽  
Main Sequence ◽  
Circumstellar Matter ◽  
Small Mass ◽  
Primary Component ◽  
Close Binary ◽  
Mass System ◽  
Future Evolution ◽  
Short Period ◽  
Low Mass

Although the evolution of binary systems has been qualitatively interpreted with the evolutionary scenario, the quantitative interpretation of any observed system is still unsatisfactory due to the difficulty of the quantitative treatment of mass and angular momentum transfer/loss. To reach a true understanding of the evolution of binary systems, we have to accumulate more observational evidence. So far, we have observed several binaries that are short-period and noncontact, and found the existence of extremely small-mass systems. In the present paper, we study another short-period (P=0.659d), noncontact, eclipsing binary system, V392 Ori. We have made photometric and spectroscopic observations of V392 Ori. The light curves are found to vary, suggesting the existence of circumstellar matter around the system. Combining the photometric and spectroscopic results, we obtain parameters describing the system; we find the mass of the primary component is only 0.6Mʘ- undermassive for its spectral and luminosity class A5V, suggesting that a considerable amount of its original mass has been lost from the system during the course of evolution. The low-mass problem is very important for investigation of the evolution of close binary systems: largemass loss within and/or after the main-sequence will have a significant influence on the future evolution of binary systems.

scholarly journals Fluorescence and Chromospheric Activity of V471 Tau

2002 ◽  
Vol 187 ◽  
pp. 167-172
Author(s):  
T.R. Vaccaro ◽  
R.E. Wilson
Keyword(s):  
Light Curve ◽  
Radial Velocity ◽  
Orbital Period ◽  
White Dwarf ◽  
Binary Star ◽  
Star Model ◽  
Orbital Inclination ◽  
Orbital Parameters ◽  
Maximum Emission ◽  
Chromospheric Activity

AbstractThe red dwarf + white dwarf eclipsing binary V471 Tau shows a variable Hα feature that varies from absorption during eclipse to maximum emission during white dwarf transit. In 1998 we obtained simultaneous BVRI photometry and Hα spectroscopy, with thorough phase coverage of the 12.5 hour orbital period. A binary star model was used with our light curve, radial velocity, and Hα data to refine stellar and orbital parameters. Combined absorption-emission profiles were generated by the model and fit to the observations, yielding a red star radius of 0.94R⊙. Orbital inclination 78° is required with this size and other known parameters. The model includes three spots 1,000 K cooler than the surrounding photosphere. The variable Hα profile was modeled as a chromospheric fluorescing region (essentially on the surface of the red star) centered at the substellar point. Additional emission seen outside our modeled profiles may be large co-rotating prominences that complicate the picture.

scholarly journals The Subdwarf Eclipsing Binary LB3459 (AA Dor)

1982 ◽  
Vol 69 ◽  
pp. 455-456
Author(s):  
R.W. Hilditch ◽  
Graham Hill ◽  
D. Kilkenny
Keyword(s):  
Light Curve ◽  
Observational Data ◽  
Spectroscopic Data ◽  
Main Sequence ◽  
Primary Component ◽  
Curve Analysis ◽  
Current Status ◽  
Evolutionary Models ◽  
Light Curve Analysis ◽  
Normal Composition

A review was presented of the currently available observational data on this evolved system, namely, uvby photometry (Kilkenny et al. 1978; paper II) radial velocities (Kilkenny et al. 1981; paper III) and a non-LTE atmosphere analysis of the primary component (Kudritski et al. 1981). Kudritski et al. conclude that T(pr) = 40000 ± 2500°K and log g = 5.3 ± 0.2 and from the spectroscopic data and light curve analysis (papers II, III) derive masses and radii for the primary and secondary components of M(pr) ≃ 0.25 M⊙, M(sec) ≃ 0.04 M⊙, R(pr) ≃ 0.16R⊙, R(sec) ≃ 0.09R⊙ respectively. Thus the primary component is a normal sd0 star whilst the secondary component is a most enigmatic object, perhaps a normal composition degenerate dwarf but of too low a mass to be on the main sequence, perhaps an evolved degenerate object but then the radius is too large. The published evolutionary models for this system (Paczynski 1980; Conti et al 1981) do not adequately describe its current status.

Absolute Properties of the Main-Sequence Eclipsing Binary Star WW Camelopardalis

2002 ◽  
Vol 123 (2) ◽  
pp. 1013-1022 ◽  
Author(s):  
Claud H. Sandberg Lacy ◽  
Guillermo Torres ◽  
Antonio Claret ◽  
Jeffrey A. Sabby
Keyword(s):  
Main Sequence ◽  
Binary Star ◽  
Eclipsing Binary ◽  
Eclipsing Binary Star

Detection of Sectoral Modes in the Eclipsing Binary KIC 4851217

2017 ◽  
Vol 14 (S339) ◽  
pp. 295-298
Author(s):  
M. Fedurco ◽  
Š. Parimucha ◽  
P. Gajdoš
Keyword(s):  
Light Curve ◽  
Frequency Analysis ◽  
Secondary Component ◽  
Frequency Range ◽  
Eclipsing Binary ◽  
Quadrupole Mode ◽  
Linear Coupling ◽  
Orbital Frequency ◽  
Short Period ◽  
Low Amplitude

AbstractKIC 4851217 is a short period eclipsing binary (P = 2.47 days) in the field of the Kepler K1 mission. As well as variability caused by the eclipses, low-amplitude pulsations are also present in the data. A frequency analysis of the residual light-curve revealed δ Sct pulsations in the frequency range from 15–21 d−1 with amplitudes up to 3.5 mmag. Strong linear coupling (fi = fp + kforb) to orbital frequency was found, indicating tidally locked modes. From an analysis of 5 selected groups of frequencies we identified a radial mode on the secondary component, 3 dipole modes (l = |m| = 1), one of them present on the secondary component, and a quadrupole mode (l = |m| = 2), also located on the secondary component.

scholarly journals The TESS light curve of the eccentric eclipsing binary 1SWASP J011351.29+314909.7 – no evidence for a very hot M-dwarf companion

2020 ◽  
Vol 498 (1) ◽  
pp. L15-L19
Author(s):  
Matthew I Swayne ◽  
Pierre F L Maxted ◽  
Vedad Kunovac Hodžić ◽  
Amaury H M J Triaud
Keyword(s):  
Light Curve ◽  
Effective Temperature ◽  
Binary Star ◽  
Mass Star ◽  
Primary Star ◽  
Eclipsing Binary ◽  
Low Mass ◽  
Stellar Models ◽  
Eclipsing Binary Star ◽  
M Dwarf

ABSTRACT A 2014 study of the eclipsing binary star 1SWASPJ011351.29+314909.7 (J0113+31) reported an unexpectedly high effective temperature for the M-dwarf companion to the 0.95-M⊙ primary star. The effective temperature inferred from the secondary eclipse depth was ∼600 K higher than the value predicted from stellar models. Such an anomalous result questions our understanding of low-mass stars and might indicate a significant uncertainty when inferring properties of exoplanets orbiting them. We seek to measure the effective temperature of the M-dwarf companion using the light curve of J0113+31 recently observed by the Transiting Exoplanet Survey Satellite (TESS). We use the pycheops modelling software to fit a combined transit and eclipse model to the TESS light curve. To calculate the secondary effective temperature, we compare the best-fitting eclipse depth to the predicted eclipse depths from theoretical stellar models. We determined the effective temperature of the M dwarf to be Teff,2 = 3208 ± 43 K, assuming log g2 = 5, [Fe/H] = −0.4, and no alpha-element enhancement. Varying these assumptions changes Teff,2 by less than 100 K. These results do not support a large anomaly between observed and theoretical low-mass star temperatures.

Absolute Properties of the Main-Sequence Eclipsing Binary Star EY Cephei

2006 ◽  
Vol 131 (5) ◽  
pp. 2664-2672 ◽  
Author(s):  
Claud H. Sandberg Lacy ◽  
Guillermo Torres ◽  
Antonio Claret ◽  
John L. Menke
Keyword(s):  
Main Sequence ◽  
Binary Star ◽  
Eclipsing Binary ◽  
Eclipsing Binary Star

SX Piscium: A near-contact mass-transferring binary with a possible brown dwarf companion

2019 ◽  
Vol 71 (5) ◽  
Author(s):  
Zhi Hua Wang ◽  
Li Ying Zhu
Keyword(s):  
Binary Star ◽  
Mass Transfer Rate ◽  
Primary Component ◽  
Brown Dwarf ◽  
Precision Data ◽  
Eclipsing Binary ◽  
Short Period ◽  
Contact Mass ◽  
Photometric Monitoring ◽  
Mass Transfers

Abstract SX Psc is a short-period Algol-type eclipsing binary whose photometric analysis has long been ignored. Our photometric monitoring of this target covered from 2001 December to 2018 November. Aside from some curves observed at the primary eclipses, the complete four-color light curves in the BVRcIc band were also obtained. Photometric solutions were determined based on the Wilson–Devinney method. It is found that SX Psc is a semidetached binary where the inner Roche lobe of the secondary component has been filled. The filling factor for the primary is about 85% along with an inclination of ${89{^{\circ}_{.}}8}$, indicating that it is a near-contact total eclipsing binary system. Meanwhile, analysis of the O − C curve revealed that the orbital period is increasing continuously at a rate of dP/dt = 4.64(4) × 10−8 d yr−1. This is due to the mass transfers from the secondary to the primary component, which is in accord with the semidetached configuration of this binary star. With the assumption of conservative evolution, the mass transfer rate is estimated as $1.96\times 10^{-8}\, M_{\odot }$ yr−1. By deducting the long-term increasing trend in the O − C diagram, the high-precision data exhibits a cyclic variation, whereas it might be caused by the Applegate mechanism. Moreover, according to the light travel-time effect, there should be a candidate brown dwarf with a mass of no less than $m\,_3 = 0.067\, M_{\odot }$ orbiting the eclipsing binary. This is perhaps a unique case for an Algol-type binary accompanied by a substellar object.

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