Spectroscopic and photometric study of the eclipsing interacting binary V495 Centauri

Rosales, J. A.; Mennickent, R. E.; Djurašević, G.; Araya, I.; Curé, M.

doi:10.1093/mnras/sty224

Cited by 11 publications

(12 citation statements)

References 38 publications

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“…V495 Cen is an eclipsing interacting binary system consisting of an evolved F-type giant and an early B-type star. The system is currently interacting and the Hα emission probably arises from the accretion disk on one of the stars rather than a decretion disk characteristic of classical Be stars (Rosales Guzmán et al 2018;Rosales et al 2019). Moreover, the spectral types of the components are unknown.…”

Section: B3 Stars Rejected As Be+ms Binariesmentioning

confidence: 99%

Investigating the lack of main-sequence companions to massive Be stars

Bodensteiner

Shenar

Sana

2020

A&A

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Context. About 20% of all B-type stars are classical Be stars – stars whose spectra imply the presence of a circumstellar decretion disk. The disk phenomenon is strongly correlated with rapid rotation, the origin of which remains unclear. It may be rooted in single- or binary-star evolution. In the framework of the binary channel, the initially more massive star transfers mass and angular momentum to the original secondary, which becomes a Be star. The system then evolves into a Be binary with a post-main-sequence companion, which, depending on the companion mass, may later be disrupted in a supernova event. Hence, if the binary channel dominates the formation of Be stars, one may expect a strong lack of close Be binaries with main sequence (MS) companions. Aims. We want to test the prediction of the binary channel. Through an extensive, star-by-star review of the literature of a magnitude-limited sample of Galactic early-type Be stars, we investigate whether Be binaries with MS companions are known to exist. Methods. Our sample is constructed from the BeSS database and cross-matched with all available literature on the individual stars. Archival and amateur spectra are used to verify the existing literature when conflicting reports are found. Results. Out of an initial list of 505 Be stars, we compile a final sample of 287 Galactic Be stars earlier than B1.5 with V ≤ 12 mag. Out of those, 13 objects were reported as Be binaries with known post-MS companions (i.e., compact objects or helium stars) and 11 as binaries with unknown, uncertain or debated companions. We find no confirmed reports of Be binaries with MS companions. For the remaining 263 targets, no significant reports of multiplicity exist in the literature, implying that they are either Be binaries with faint companions, or truly single. Conclusions. The clear lack of reported MS companions to Be stars, which stands in contrast to the high number of detected B+B MS binaries, strongly supports the hypothesis that early-type Be stars are binary interaction products that spun up after mass and angular momentum transfer from a companion star. Taken at face value, our results may suggest that a large majority of the early-type Be stars have formed through binary mass-transfer.

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Section: B3 Stars Rejected As Be+ms Binariesmentioning

confidence: 99%

Investigating the lack of main-sequence companions to massive Be stars

Bodensteiner

Shenar

Sana

2020

A&A

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“…Only a few DPVs have been studied spectroscopically in detail and therefore few of them posses relatively well-determined orbital and stellar parameters; 9 Galactic DPVs and the LMC DPV OGLE05155332-6925581 are documented by Mennickent, Otero, & Kołaczkowski (2016) and recently stellar and orbital parameters were provided for V 495 Cen by Rosales Guzmán et al (2018). Our study of OGLE-LMC-DPV-065 presented in this paper is the second spectroscopic study of an LMC DPV.…”

Section: Discussionmentioning

confidence: 96%

On the long-cycle variability of the Algol OGLE-LMC-DPV-065 and its stellar, orbital, and disc parameters

Mennickent

Cabezas

Djurašević

et al. 2019

Monthly Notices of the Royal Astronomical Society

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OGLE-LMC-DPV-065 is an interacting binary whose double-hump long photometric cycle remains hitherto unexplained. We analyze photometric time series available in archive datasets spanning 124 years and present the analysis of new high-resolution spectra. A refined orbital period is found of 10. d 0316267 ± 0. d 0000056 without any evidence of variability. In spite of this constancy, small but significant changes in timings of the secondary eclipse are detected. We show that the long period continuously decreases from 350 to 218 days during 13 years, then remains almost constant for about 10 years. Our study of radial velocities indicates a circular orbit for the binary and yields a mass ratio of 0.203 ± 0.001. From the analysis of the orbital light curve we find that the system contains 13.8 and 2.81 M stars of radii 8.8 and 12.6 R and absolute bolometric magnitudes -6.4 and -3.0, respectively. The orbit semimajor axis is 49.9 R and the stellar temperatures are 25460 K and 9825 K. We find evidence for an optically and geometrically thick disk around the hotter star. According to our model, the disk has a radius of 25 R , central and outer vertical thickness of 1.6 R and 3.5 R , and temperature of 9380 K at its outer edge. Two shock regions located at roughly opposite parts of the outer disk rim can explain the light curves asymmetries. The system is a member of the double periodic variables and its relatively high-mass and long photometric cycle make it similar in some aspects to β Lyrae.

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“…An optimized simplex algorithm was used to solve the inverse problem adjusting the light curve with the best stellar-orbitaldisk parameters for the system. The basic elements of the model, together with the light-curve synthesis procedure, can be found in the literature (Djurašević 1992(Djurašević , 1996, along with new and improved versions (Djurašević et al 2008), which have been applied to several close binaries in the past (e.g., Mennickent & Djurašević 2013;Rosales Guzmán et al 2018;Mennickent et al 2020b).…”

Section: The Light Curve Modelmentioning

confidence: 99%

Model for the long and orbital brightness variability of the β Lyrae type binary OGLE-BLG-ECL-157529

Mennickent

Djurašević

2021

A&A

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Context. Some close binaries of the β Lyrae type show photometric cycles longer than the orbital one, which are possibly related to changes in their accretion disks. Aims. We aim to understand the short- and long-scale morphologic changes observed in the light curve of the eclipsing system OGLE-BLG-ECL-157529. In particular, we want to shed light on the contribution of the disk variability to these changes, especially those related to the long cycle, occurring on timescales of hundreds of days. Methods. We studied I-band Optical Gravitational Lensing Experiment (OGLE) photometric times series spanning 18.5 years, constructing disk models by analyzing the orbital light curve at 52 different consecutive epochs. An optimized simplex algorithm was used to solve the inverse problem by adjusting the light curve with the best stellar-orbital-disk parameters for the system. We applied an analysis of principal components to the parameters to evaluate their dependence and variability. We constructed a description of the mass transfer rate in terms of disk parameters. Results. We find that the overall light variability can be understood in terms of a variable mass transfer rate and variable accretion disk. The system brightness at orbital phase 0.25 follows the long cycle and is correlated with the mass transfer rate and the disk thickness. The long-cycle brightness variations can be understood in terms of differential occultation of the hotter star by a disk of variable thickness. Our model fits the overall light curve during 18.5 years well, including epochs of reversal of main and secondary eclipse depths. The disk radius cyclically change around the tidal radius, decoupled from changes in the mass transfer rate or system brightness, suggesting that viscous delay might explain the non-immediate response. Although the disk is large and fills a large fraction of the hot star Roche lobe, Lindblad resonance regions are far beyond the disk, excluding viscous dissipation as a major source of photometric variability.

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Spectroscopic and photometric study of the eclipsing interacting binary V495 Centauri

Cited by 11 publications

References 38 publications

Investigating the lack of main-sequence companions to massive Be stars

Investigating the lack of main-sequence companions to massive Be stars

On the long-cycle variability of the Algol OGLE-LMC-DPV-065 and its stellar, orbital, and disc parameters

Model for the long and orbital brightness variability of the β Lyrae type binary OGLE-BLG-ECL-157529

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