The eclipsing LMC star OGLE 05155332−6925581: a clue for double periodic variables★

Mennickent, R. E.; Kołaczkowski, Z.; Michalska, G.; Pietrzyński, G.; Gallardo, R.; Cidale, L. S.; Granada, A.; Gieren, W.

doi:10.1111/j.1365-2966.2008.13696.x

Cited by 27 publications

(38 citation statements)

References 29 publications

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“…Moreover, it is not clear whether the hotspot mechanism can work with WRLOF, because of the lower mass-transfer rates. Double periodic variables (DPVs) are interacting binaries exhibiting two closely linked periodic variations, the shortest one being the orbital period (Mennickent et al 2003(Mennickent et al , 2005(Mennickent et al , 2008 and the second one of unknown nature but probably linked to the variations in the strength of the disc wind (Mennickent et al 2012). They are considered as one specific evolutionary step for the more massive Algols.…”

Section: Stellar Samplesmentioning

confidence: 99%

Non-conservative evolution in Algols: where is the matter?

Deschamps

Braun

Jorissen

et al. 2015

A&A

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Context. There is indirect evidence of non-conservative evolutions in Algols. However, the systemic mass-loss rate is poorly constrained by observations and generally set as a free parameter in binary-star evolution simulations. Moreover, systemic mass loss may lead to observational signatures that still need to be found. Aims. Within the "hotspot" ejection mechanism, some of the material that is initially transferred from the companion star via an accretion stream is expelled from the system due to the radiative energy released on the gainer's surface by the impacting material. The objective of this paper is to retrieve observable quantities from this process and to compare them with observations. Methods. We investigate the impact of the outflowing gas and the possible presence of dust grains on the spectral energy distribution (SED). We used the 1D plasma code Cloudy and compared the results with the 3D Monte-Carlo radiative transfer code Skirt for dusty simulations. The circumbinary mass-distribution and binary parameters were computed with state-of-the-art binary calculations done with the Binstar evolution code. Results. The outflowing material reduces the continuum flux level of the stellar SED in the optical and UV. Because of the timedependence of this effect, it may help to distinguish between different ejection mechanisms. If present, dust leads to observable infrared excesses, even with low dust-to-gas ratios, and traces the cold material at large distances from the star. By searching for this dust emission in the WISE catalogue, we found a small number of Algols showing infrared excesses, among which the two rather surprising objects SX Aur and CZ Vel. We find that some binary B[e] stars show the same strong Balmer continuum as we predict with our models. However, direct evidence of systemic mass loss is probably not observable in genuine Algols, since these systems no longer eject mass through the hotspot mechanism. Furthermore, owing to its high velocity, the outflowing material dissipates in a few hundred years. If hot enough, the hotspot may produce highly ionised species, such as Si iv, and observable characteristics that are typical of W Ser systems. Conclusions. If present, systemic mass loss leads to clear observational imprints. These signatures are not to be found in genuine Algols but in the closely related β Lyraes, W Serpentis stars, double periodic variables, symbiotic Algols, and binary B[e] stars. We emphasise the need for further observations of such objects where systemic mass loss is most likely to occur.

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Section: Stellar Samplesmentioning

confidence: 99%

Non-conservative evolution in Algols: where is the matter?

Deschamps

Braun

Jorissen

et al. 2015

A&A

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“…Using the data obtained after a photometric and spectroscopic campaign carried out during 2008-2011, Barría et al (2013 determined the fundamental stellar and orbital parameters of this binary. Their techniques involved the separation of the DQ Vel composite spectra, radial velocity (RV) measurements, and a multicomponent fit to the V-band ASAS light curve.…”

Section: Introductionmentioning

confidence: 99%

Exploring the long-term variability and evolutionary stage of the interacting binary DQ Velorum

Barría

Mennickent

Graczyk

et al. 2014

A&A

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Aims. In order to better understand the double periodic variable (DPV) phenomenon, we analyse a series of optical spectra of the DPV system DQ Velorum during much of its long-term cycle. In addition, we investigate the evolutionary history of DQ Vel using theoretical evolutionary models to obtain the best representation for the current observed stellar and orbital parameters of the binary. We investigate the evolution of DQ Vel through theoretical evolutionary models to estimate the age and the mass transfer rate which are then compared with those of its twin V393 Scorpii. Methods. We subtracted the donor star contribution from the composite spectra of DQ Vel using a synthetic spectrum as a donor template. Donor-subtracted spectra covering around 60% of the long-term cycle allowed us to investigate time-modulated spectral variations of the gainer star plus the disc. We used Gaussian fits to measure the equivalent widths (EWs) of Balmer and helium lines in the separated spectra during the long-term cycle and thus analyse EW variabilities. We compared the observed stellar parameters of the system with a grid of theoretical evolutionary tracks computed under a conservative and a non-conservative evolution regime. Results. We have found that the EW of Balmer and helium lines in the donor-subtracted spectra are modulated with the long-term cycle. We observe a strengthening in the EWs in all analysed spectral features at the minimum of the long-term cycle which might be related to an extra line emission during the maximum of the long-term variability. Difference spectra obtained at the secondary eclipse support this scenario. We have found that a non-conservative evolutionary model where DQ Vel has lost mass at some stage of its binary history, is a better representation of the current observed properties of the system. The best evolutionary model suggests that DQ Vel has an age of 7.40 × 10 7 yr and is currently in a low mass transfer rate (−9.8 × 10 −9 M /yr) stage, after a mass transfer burst episode. Comparing the evolutionary stages of DQ Vel and V393 Sco we observed that the former is an older system with a lower mass transfer rate. This might explain the differences observed in the physical parameters of their accretion discs.

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“…The short-term variability corresponds to the orbital motion of the binary while the long-term variability A&A 552, A63 (2013) is still not completely understood. DPVs have been interpreted as semi-detached binaries showing cycles of mass loss into the interstellar medium (Mennickent et al 2008(Mennickent et al , 2012b.…”

Section: Introductionmentioning

confidence: 99%

Fundamental stellar and accretion disc parameters of the eclipsing binary DQ Velorum

Barría

Mennickent

Schmidtobreick

et al. 2013

A&A

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Context. To add to the growing collection of well-studied double periodic variables (DPVs) we have carried out the first spectroscopic and photometric analysis of the eclipsing binary DQ Velorum to obtain its main physical stellar and orbital parameters. Aims. Combining spectroscopic and photometric observations that cover several orbital cycles allows us to estimate the stellar properties of the binary components and the orbital parameters. We also searched for circumstellar material around the more massive star. Methods. We separated DQ Velorum composite spectra and measured radial velocities with an iterative method for double spectroscopic binaries. We obtained the radial velocity curves and calculated the spectroscopic mass ratio. We compared our single-lined spectra with a grid of synthetic spectra and estimated the temperature of the stars. We modeled the V-band light curve with a fitting method based on the simplex algorithm, which includes an accretion disc. To constrain the main stellar parameters we fixed the mass ratio and donor temperature to the values obtained by our spectroscopic analysis. Results. We obtain a spectroscopic mass ratio q = 0.31 ± 0.03 together with donor and gainer masses M d = 2.2 ± 0.2 M , M g = 7.3 ± 0.3 M , the radii R d = 8.4 ± 0.2 R , R g = 3.6 ± 0.2 R and temperatures T d = 9400 ± 100 K, T g = 18 500 ± 500 K for the stellar components. We find that DQ Vel is a semi-detached system consisting of a B3V gainer and an A1III donor star plus an extended accretion disc around the gainer. The disc is filling 89% of the gainer Roche lobe with a temperature of 6580 ± 300 K at the outer radius. It has a concave shape that is thicker at its edge (d e = 0.6 ± 0.1 R ) than at its centre (d c = 0.3 ± 0.1 R ). We find a significant sub-orbital frequency of 0.19 d −1 in the residuals of the V-band light curve, which we interpret as a pulsation of an slowly pulsating B-type (SPB) of a gainer star. We also estimate the distance to the binary (d ∼ 3.1 kpc) using the absolute radii, apparent magnitudes, and effective temperatures of the components found in our study.

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The eclipsing LMC star OGLE 05155332−6925581: a clue for double periodic variables★

Cited by 27 publications

References 29 publications

Non-conservative evolution in Algols: where is the matter?

Non-conservative evolution in Algols: where is the matter?

Exploring the long-term variability and evolutionary stage of the interacting binary DQ Velorum

Fundamental stellar and accretion disc parameters of the eclipsing binary DQ Velorum

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