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

Barría, Daniela; Mennickent, R. E.; Graczyk, D.; Kołaczkowski, Z.

doi:10.1051/0004-6361/201322644

Cited by 9 publications

(10 citation statements)

References 17 publications

(39 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They conclude explaining the long photometric cycle in terms of variable strength of a bipolar disk wind. We notice that the extra line emission during the maximum of the long-cycle was also observed in DQ Vel (Barría et al 2014) and AU Mon (Barría and Mennickent 2011). All these findings bring similarities with the case of β Lyrae.…”

Section: Evidence Of Mass Loss and Hotspot Windsupporting

confidence: 58%

Long photometric cycles in hot algols

Mennickent

2017

SERBIAN ASTRON J

View full text Add to dashboard Cite

We summarize the development of the field of Double Periodic Variables (DPVs, Mennickent et al. 2003) during the last fourteen years, placing these objects in the context of intermediate-mass close interacting binaries similar to ? Persei (Algol) and ? Lyrae (Sheliak) which are generally called Algols. DPVs show enigmatic long photometric cycles lasting on average about 33 times the orbital period, and have physical properties resembling, in some aspects, ? Lyrae. About 200 of these objects have been found in the Galaxy and the Magellanic Clouds. Light curve models and orbitally resolved spectroscopy indicate that DPVs are semi-detached interacting binaries consisting of a near main-sequence B-type star accreting matter from a cooler giant and surrounded by an optically thick disc. This disc contributes a significant fraction of the system luminosity and its luminosity is larger than expected from the phenomenon of mass accretion alone. In some systems, an optically thin disc component is observed in well developed Balmer emission lines. The optically thick disc shows bright zones up to tens percent hotter than the disc, probably indicating shocks resulting from the gas and disc stream dynamics. We conjecture that a hotspot wind might be one of the channels for a mild systemic mass loss, since evidence for jets, winds or general mass loss has been found in ? Lyrae, AUMon, HD170582, OGLE05155332-6925581 and V393 Sco. Also, theoretical work by Van Rensbergen et al. (2008) and Deschamps et al. (2013) suggests that hotspot could drive mass loss from Algols. We give special consideration to the recently published hypothesis for the long-cycle, consisting of variable mass transfer driven by a magnetic dynamo (Schleicher and Mennickent 2017). The Applegate (1992) mechanism should modify cyclically the equatorial radius of the chromospherically active donor producing cycles of enhanced mass loss through the inner Lagrangian point. Chromospheric emission in V393 Sco, an optically thicker hotspot in the high-state of HD170582 and evidence for magnetic fields in many Algols are observational facts supporting this picture. One of the open questions for this scenario is why, among the Algols showing evidence for magnetic fields, the DPV long-cycle is present only under some combinations of stellar parameters, particularly those including the B-type gainers. Other open questions are what are the descendants of these interesting binaries, how much mass contain the discs around the likely rapidly rotating gainers, and the role played by the outflows through the Lagrangian L2 and L3 points reported in a couple of systems.

show abstract

Section: Evidence Of Mass Loss and Hotspot Windsupporting

confidence: 58%

Long photometric cycles in hot algols

Mennickent

2017

SERBIAN ASTRON J

View full text Add to dashboard Cite

show abstract

“…It is then possible that an increase of the energy released at the hotspot produces a stronger hotspot wind at long cycle maximum, as modeled by van Rensbergen et al (2008). This strengthened wind can be seen as the extra light emitting source reported for instance in V393 Scorpii (Mennickent et al 2012b), DQ Velorum (Barría et al 2014) and β Lyrae (Harmanec et al 1996;Hoffman et al 1998;Ak et al 2007). In this case the hotspot should be brighter at long cycle maximum, something revealed by Doppler tomography in the DPV HD 170582 (Mennickent et al 2016b).…”

Section: Discussionmentioning

confidence: 96%

A dynamo mechanism as the potential origin of the long cycle in double periodic variables

Schleicher¹,

Mennickent²

2017

A&A

View full text Add to dashboard Cite

The class of Double Period Variables (DPVs) consists of close interacting binaries, with a characteristic long period that is an order of magnitude longer than the corresponding orbital period, many of them with a characteristic ratio of about 3.5 × 10 1 . We consider here the possibility that the accretion flow is modulated as a result of a magnetic dynamo cycle. Due to the short binary separations, we expect the rotation of the donor star to be synchronized with the rotation of the binary due to tidal locking. We here present a model to estimate the dynamo number and the resulting relation between the activity cycle length and the orbital period, as well as an estimate for the modulation of the mass transfer rate. The latter is based on Applegate's scenario, implying cyclic changes in the radius of the donor star and thus in the mass transfer rate as a result of magnetic activity. Our model is applied to a sample of 17 systems with known physical parameters, 10 also with known orbital periods. In spite of the uncertainties of our simplified framework, the results show a reasonable agreement, indicating that a dynamo interpretation is potentially feasible. At the same time, we note that the orbital period variations resulting from Applegate's model are sufficiently small to be consistent with the data. We conclude that both larger samples with known physical parameters as well as potential direct probes of the magnetism of the donor star, including cold spots as well as polarization, will be valuable to further constrain the nature of these systems.

show abstract

“…When the gas flow from the secondary component hits the disc, not directly the primary star, a disc hotspot occurs and an increase of the energy released at the hotspot produces a stronger hotspot wind [23], which may also cause period change in the system. Such an enhanced wind effect has been identified in systems such as DQ Vel (T 2 = 9350 K), V393 Sco (T 2 = 7950 K), and Beta Lyr (T 2 = 13200 K) (see [24][25][26][27]). Therefore, our future plan is to study the indicators of such mass transfer and mass loss in V822 Aql in detail through a simultaneous analysis of photometric and spectroscopic data as done in [28].…”

Section: Resultsmentioning

confidence: 99%

Revealing the true nature of the multiple system V822 Aql

Bakıș¹

2018

Turk J Phys

View full text Add to dashboard Cite

Given the brightness, the V822 Aql multiple star system is photometric and spectroscopically neglected. In this study high-resolution echelle spectra of the system were obtained and were used to calculate the mass ratio of the system by determining the individual lines of the components for the first time. According to this, the close binary consists of two components revolving in a circular orbit with velocity semiamplitudes of K 1 = 45.5 ± 0.8 km/s and K 2 = 204.9 ± 0.9 km/s (q = 0.22 ± 0.01), respectively. In addition, the orbital period analysis showed a highly eccentric orbit for the close binary together with a third body moving in a 49-year orbit. The high mass function is evidence for the binary nature of the third body.

show abstract

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

Cited by 9 publications

References 17 publications

Long photometric cycles in hot algols

Long photometric cycles in hot algols

A dynamo mechanism as the potential origin of the long cycle in double periodic variables

Revealing the true nature of the multiple system V822 Aql

Contact Info

Product

Resources

About