Optical spectroscopic monitoring of the Herbig Be binary star HD 200775: New maximum of activity and refinement of the orbital period

2015 ◽  
Vol 70 (3) ◽  
pp. 299-309 ◽  
Author(s):  
A. P. Bisyarina ◽  
A. M. Sobolev ◽  
S. Yu. Gorda ◽  
S. Yu. Parfenov
Keyword(s):  
Orbital Period ◽  
Binary Star ◽  
Spectroscopic Monitoring

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 Origin of the orbital period change in contact binary stars

2019 ◽  
Vol 28 (06) ◽  
pp. 1950044 ◽  
Author(s):  
V. V. Sargsyan ◽  
H. Lenske ◽  
G. G. Adamian ◽  
N. V. Antonenko
Keyword(s):  
Orbital Period ◽  
Binary Stars ◽  
Binary Systems ◽  
Binary Star ◽  
Period Change ◽  
Mass Asymmetry ◽  
Contact Binary Stars ◽  
Contact Binary ◽  
Energy Formula ◽  
Orbital Periods

The evolution of contact binary star systems in mass asymmetry (transfer) coordinate is considered. The orbital period changes are explained by an evolution in mass asymmetry towards the symmetry (symmetrization of binary system). It is predicted that decreasing and increasing orbital periods are related, respectively, with the nonoverlapping and overlapping stage of the binary star during its symmetrization. A huge amount of energy [Formula: see text][Formula: see text]J is converted from the potential energy into internal energy of the stars during the symmetrization. As shown, the merger of stars in the binary systems, including KIC 9832227, is energetically an unfavorable process. The sensitivity of the calculated results to the values of total mass and orbital angular momentum is analyzed.

scholarly journals The short orbital period binary star at the heart of the planetary nebula M 3-1★

2018 ◽  
Vol 482 (1) ◽  
pp. L75-L79 ◽  
Author(s):  
David Jones ◽  
Henri M J Boffin ◽  
Paulina Sowicka ◽  
Brent Miszalski ◽  
Pablo Rodríguez-Gil ◽  
...  
Keyword(s):  
Orbital Period ◽  
Planetary Nebula ◽  
Binary Star

scholarly journals Massive binaries as progenitors for stellar explosions

2015 ◽  
Vol 11 (A29B) ◽  
pp. 208-208
Author(s):  
Selma de Mink
Keyword(s):  
Strong Interaction ◽  
Orbital Period ◽  
Binary Systems ◽  
Massive Stars ◽  
Binary Star ◽  
Close Binary ◽  
Population Synthesis ◽  
Close Binary Systems ◽  
Star Models ◽  
The Masses

AbstractThe majority of young massive stars are found in close binary systems. Recently, dedicated observingcampaigns have provided strong constraints on the binary fraction as well as the distribution of the parameters thatcharacterize the binary systems: the masses of both components, the orbital period and eccentricities. Most strikinglythese findings imply that the majority of massive stars experience strong interaction (roche lobe overflow, a commonenvelope phase and or a merger) with a binary companion before their final explosion. I will discuss recent resultsfrom detailed binary star models and population synthesis models.

scholarly journals Formation of cold clumps and filaments around superbubbles

2015 ◽  
Vol 11 (A29B) ◽  
pp. 231-231
Author(s):  
E. Ntormousi ◽  
P. Hennebelle ◽  
J. Dawson ◽  
F. Del Sordo
Keyword(s):  
Strong Interaction ◽  
Orbital Period ◽  
Binary Systems ◽  
Massive Stars ◽  
Binary Star ◽  
Close Binary ◽  
Population Synthesis ◽  
Common Envelope ◽  
Star Models ◽  
The Masses

AbstractThe majority of young massive stars are found in close binary systems. Recently, dedicated observing campaigns have provided strong constraints on the binary fraction as well as the distribution of the parameters that characterize the binary systems: the masses of both components, the orbital period and eccentricities. Most strikingly these findings imply that the majority of massive stars experience strong interaction (roche lobe overflow, a common envelope phase and or a merger) with a binary companion before their final explosion. I will discuss recent results from detailed binary star models and population synthesis models.

scholarly journals Complex Period Variations of the Neglected W UMa-type Binary System NY Lyrae

2009 ◽  
Vol 26 (1) ◽  
pp. 7-10 ◽  
Author(s):  
S.-B. Qian ◽  
L. Liu ◽  
L.-Y. Zhu
Keyword(s):  
Binary System ◽  
Orbital Period ◽  
Binary Star ◽  
Period Increase ◽  
Photometric And Spectroscopic Observations ◽  
Period Variations ◽  
Cyclic Oscillation ◽  
Careful Investigation ◽  
Interesting System

AbstractOrbital-period variations of the neglected W UMa-type binary star, NY Lyr, were analyzed based on two newly determined eclipse times together with the others compiled from the literature. A cyclic oscillation with a period of 82.1 yr and an amplitude of 0.0247 d was discovered to be superimposed on a continuous period increase (dP/dt = +1.33 × 10−7 d yr−1). After the long-term period increase and the large-amplitude cyclic oscillation were removed from the O–C diagram, the residuals suggest that there is another small-amplitude period oscillation (A4 = 0.0053 d, P4 = 19.4 years) in the orbital period changes. As in the cases of AH Cnc and AD Cnc, both the continuous period increase and the two cyclic period oscillations make NY Lyr an interesting system to study in the future. In order to understand the evolutionary state of the binary system, new photometric and spectroscopic observations and a careful investigation on those data are needed.

scholarly journals Mid-Cycle Observations of CR Boo and Estimation of the System’s Parameters

Data ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 113
Author(s):  
Daniela Boneva ◽  
Svetlana Boeva ◽  
Yanko Nikolov ◽  
Zorica Cvetković ◽  
Radoslav Zamanov
Keyword(s):  
Binary System ◽  
Observational Data ◽  
Orbital Period ◽  
Binary Star ◽  
Contact Point ◽  
Bright Spot ◽  
V Band ◽  
Phase Rotation

We present observations (with NAO Rozhen and AS Vidojevica telescopes) of the AM Canum Venaticorum (AM CVn) binary star CR Bootis (CR Boo) in the UBV bands. The data were obtained in two nights in July 2019, when the V band brightness was in the range of 16.1–17.0 mag. In both nights, a variability for a period of 25 ± 1 min and amplitude of about 0.2 magnitudes was visible. These brightness variations are most likely indications of “humps”. During our observational time, they appear for a period similar to the CR Boo orbital period. A possible reason of their origin is the phase rotation of the bright spot, placed in the contact point of the infalling matter and the outer disc edge. We estimated some of the parameters of the binary system, on the base of the observational data.

scholarly journals BRITE photometry of the massive post-RLOF system HD149 404

2018 ◽  
Vol 621 ◽  
pp. A15 ◽  
Author(s):  
G. Rauw ◽  
A. Pigulski ◽  
Y. Nazé ◽  
A. David-Uraz ◽  
G. Handler ◽  
...  
Keyword(s):  
Orbital Period ◽  
Binary Star ◽  
Rotation Period ◽  
Photometric Data ◽  
Roche Lobe ◽  
Primary Star ◽  
Orbital Inclination ◽  
Secondary Star ◽  
Star Binary ◽  
Orbital Part

Context. HD 149 404 is an evolved non-eclipsing O-star binary that has previously undergone a Roche lobe overflow interaction. Aims. Understanding some key properties of the system requires a determination of the orbital inclination and of the dimensions of the components. Methods. The BRITE-Heweliusz satellite was used to collect photometric data of HD 149 404. Additional photometry was retrieved from the SMEI archive. These data were analysed using a suite of period search tools. The orbital part of the lightcurve was modelled with the nightfall binary star code. The Gaia-DR2 parallax of HD 149 404 was used to provide additional constraints. Results. The periodograms reveal a clear orbital modulation of the lightcurve with a peak-to-peak amplitude near 0.04 mag. The remaining non-orbital part of the variability is consistent with red noise. The lightcurve folded with the orbital period reveals ellipsoidal variations, but no eclipses. The minimum when the secondary star is in inferior conjunction is deeper than the other minimum due to mutual reflection effects between the stars. Combined with the Gaia-DR2 parallaxes, the photometric data indicate an orbital inclination in the range of 23°–31° and a Roche lobe filling factor of the secondary larger than or equal to 0.96. Conclusions. The luminosity of the primary star is consistent with its present-day mass, whereas the more evolved secondary appears overluminous for its mass. We confirm that the primary’s rotation period is about half the orbital period. Both features most probably stem from the past Roche lobe overflow episode.

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.

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.

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