Transient photometric disturbances in Algol-like binaries

Olson, Edward C.

doi:10.1086/160206

Cited by 31 publications

(23 citation statements)

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“…This feature may follow from bulge radiation normal to the orbital plane (not in the observer's line of sight), and cooling associated with the increased radiating area. We found similar, but smaller, bursts in the stream-impact Algol RW Tauri (P = 2.77 day) (Olson 1982), and hints of disturbances in several other short-period Algols. Among longperiod Algols (P> about 10 day), E. C. Olson & Etzel (2009, in preparation) conclude, from the behavior of Hα accretion disk emission, that small transfer bursts occur in these binaries as well.…”

Section: Discussionsupporting

confidence: 63%

Mass Transfer Variations in Ux Monocerotis: Eight Years of Automated Photometric Monitoring

Olson

Henry

Etzel

2009

The Astronomical Journal

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We analyze eight years (1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) of automated photometric observations of the active Algol binary UX Monocerotis to search for mass transfer bursts similar to those seen in U Cephei. The largest photometric anomaly is the mean gainer luminosity difference between the stream-impact hemisphere and the opposite hemisphere. We find an updated Wilson-Devinney solution for earlier six-color observations. The UX Mon donor star fills its Roche lobe and the gainer nearly fills its rotational lobe. Instead of isolated bursts of the U Cep type, we found nearly continuous brightness fluctuations likely produced by variable mass transfer. We discuss implications for mass transfer.

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Section: Discussionsupporting

confidence: 63%

Mass Transfer Variations in Ux Monocerotis: Eight Years of Automated Photometric Monitoring

Olson

Henry

Etzel

2009

The Astronomical Journal

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“…Short-period light variability of RZ Cas was reported by different authors (Olson 1982;Edwin & Gears 1992;Davis & Balonek 1996). Ohshima et al (1998Ohshima et al ( , 2001 were the first who showed that this variability is caused by oscillations of the primary with a dominant frequency of 64.2 c d −1 .…”

Section: Introductionmentioning

confidence: 62%

“…The primary minimum is a partial eclipse (Narusawa et al 1994) and the light-curve is distorted, possibly by star spots (e.g. Maxted et al 1994) and/or by non-symmetric circumstellar matter (Olson 1982; Send offprint requests to: H. Lehmann, e-mail: lehm@tls-tautenburg. de The research is based on spectroscopic observations made with the 2-m telescope at the Thüringer Landessternwarte Tautenburg, Germany.…”

Section: Introductionmentioning

confidence: 99%

The eclipsing binary star RZ Cas

Lehmann

Mkrtichian

2003

A&A

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Abstract. In a first report on the results of a multi-site campaign in 2001 of photometric and spectroscopic observations of the active semi-detached Algol-type system RZ Cas, we concentrate on the radial velocity (RV) variations. Using weak absorption lines we obtain an improved orbital solution for both components. In the orbital RV curve we observe a strong, asymmetric rotation effect. For the first time we detect rapid spectroscopic multi-mode pulsations in an Algol system. Whereas the photometrically observed oscillations were dominated by monoperiodic pulsations at frequency 64. . Both modes show amplitude variations over the orbital phase with a a minimum at orbital phases φ = 0.6-0.8 and a maximum just after the primary minimum ( f 2 ) and at φ ≈ 0.25 ( f 1 ). The different shape of amplitude modulation of the f 1 and f 2 modes points to different (l, m) mode structures. The modulation itself can be explained by assuming a variable extinction due to gas streams and an inhomogeneous accretion annulus that weakens the light from different regions of the primary depending on its orbital position. This assumption is well supported by the gas density distribution obtained in preliminary hydrodynamic simulations. We found strong variations and cycle-to-cycle variable shapes of the orbital RV-curves of Balmer lines that have maximum magnitude in the Hα line indicating a strong variability of mass-transfer rates and a non-stationary circumbinary envelope.

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“…During primary minimum, a partial eclipse is observed . Olson (1982) and Varricatt et al (1998) found evidence of circumstellar matter surrounding the primary. Single-peaked emission originating from a structure located between the two stars was detected by Richards & Albright (1999).…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic modeling of oscillating Algol-type stars

Tkachenko

Lehmann

Mkrtichian

2009

A&A

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Aims. Based on time series of high-resolution spectra, we investigate the oEA star (i.e., Algol-type eclipsing binary with an oscillating primary component) RZ Cas to derive precise system and atmospheric parameters and search for phases of rapid mass-transfer and its effects on various system parameters at different epochs of observations. Methods. We combine a variety of methods including the KOREL program to decompose the components of the spectra and determine the orbital solution, the SynthV program to analyze the disentangled spectra by computing synthetic spectra based on atmosphere models, and the newly developed program Shellspec07_inverse to compute optimized stellar parameters from composite line profiles at all orbital phases. Results. Based on spectra taken in 2006, the RZ Cas system can be modeled accurately by assuming that only two stars are present. For spectra acquired in 2001, we obtained an improved solution by adding a light attenuating accretion annulus surrounding the primary, but were unable to model remaining structures in the O-C value distribution. The primary of RZ Cas is a normal A-type star that shows no λ Boo signatures, both components have close to solar abundance. The derived mass of the primary and the separation of the components are slightly smaller than previously assumed. The effective temperature of the primary of 8900 K, is 300 K higher than derived before. The Roche-lobe-filling secondary is assumed to have a large cool spot on its surface pointing towards the primary.

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Transient photometric disturbances in Algol-like binaries

Cited by 31 publications

References 0 publications

Mass Transfer Variations in Ux Monocerotis: Eight Years of Automated Photometric Monitoring

Mass Transfer Variations in Ux Monocerotis: Eight Years of Automated Photometric Monitoring

The eclipsing binary star RZ Cas

Spectroscopic modeling of oscillating Algol-type stars

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