Evidence of magnetic activity in short-period Algol binaries

Richards, Mercedes T.; Albright, Geary E.

doi:10.1086/191821

Cited by 47 publications

(54 citation statements)

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“…The resulting "" di †erence proÐles ÏÏ represented all the emission and excess absorption in the system from circumstellar material. Analysis of the di †erence proÐles revealed evidence of an asymmetric transient accretion disk (Richards 1992) and a localized highdensity H II region (Richards 1993). These regions were not found in previous studies because the emission from the circumstellar gas is weak relative to the continuum level, and the partial eclipses of the system ensure that the light from the primary star always dominates the total light from the system.…”

Section: Rw T Aurimentioning

confidence: 81%

“…In addition to a transient accretion disk inferred from the observations, other regions have been identiÐed including a denser region near the location of the impact called a "" localized region,ÏÏ and a "" high rotational velocity region ÏÏ (e.g., Richards 1992Richards , 1993Vesper & Honeycutt 1993). The gas stream itself can be a dominant emission source (Richards, Albright, & Bowles 1995) in addition to a circumstellar bulge, in the form of a hot band around the equator of the mass gainer (Olson 1980).…”

Section: Historical Backgroundmentioning

confidence: 99%

“…The selection criteria were that they be bright systems, observable from the northern hemisphere, and with reliable previously published spectroscopic and photometric orbital elements and stellar parameters. The orbital and stellar parameters for the systems studied are presented in Tables 2 and 3. Prior to this work, there were only Ðve short-period Algol systems for which detailed spectroscopic investigations of the accretion regions had been made : RW Tau (Kaitchuck & Honeycutt 1982 ;Vesper & Honeycutt 1993), U Cep (Crawford 1981 ;Kaitchuck, Honeycutt, & Faulkner 1989), TZ Eri (Kaitchuck & Park 1988), b Per (Richards 1986(Richards , 1993Gillet, Mouchet, & North 1989), and TX UMa (Albright & Richards 1993). The Ðrst three systems (RW Tau, U Cep, and TZ Eri) are all totally eclipsing systems, while b Per and TX UMa were the Ðrst partially eclipsing systems studied in detail.…”

Section: Systems Studiedmentioning

confidence: 99%

“…Additional evidence of circumstellar material was found by Kreiner & Tremko (1980) in the form of changes in the depth of primary minimum of 0.11 mag. Richards & Albright (1993) analyzed Ha di †erence proÐles obtained from 1991 February to 1992 March. They found evidence of deep redshifted absorption during primary eclipse, weaker redshifted absorption at other phases, and strong blueshifted and redshifted emission outside of primary eclipse.…”

Section: Rw T Aurimentioning

confidence: 99%

“…Richards & Albright (1996) used Doppler tomography to show similarities between the Ha emission structures in the RS CVn binary HR 1099 and Algols like RS Vul, b Per, TX UMa, and RW Tau. A review of the magnetic activity in Algol systems is given by Richards & Albright (1993).…”

Section: Introductionmentioning

confidence: 99%

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Morphologies of Hα Accretion Regions in Algol Binaries

Richards

Albright

1999

ASTROPHYS J SUPPL S

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109

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We have investigated a group of 18 Algol-type binaries to determine the general morphologies and physical properties of the accretion regions in these systems. The systems studied were V505 Sgr, RZ Cas, AI Dra, TV Cas, TW Cas, d Lib, RW Tau, TW Dra, b Per, TX UMa, U Sge, S Equ, U CrB, RS Vul, SW Cyg, CX Dra, TT Hya, and AU Mon, in order of increasing orbital period P \ 1.18È11.11 days. In addition, the RS CVn-type binary HR 1099 (V711 Tau) was observed to illustrate the appearance of chromospheric Ha emission. Nearly 2200 time-resolved Ha spectra were collected from 1992 March to 1994 December with the McMath-Pierce Solar Telescope at NSO and mostly with the Coude Feed Telescope at KPNO. The spectra were obtained at phases around the entire orbit of each binary and were closely spaced to permit the detection of transitions in the proÐles. Moreover, the spectra were obtained typically within three orbital cycles to reduce the inÑuence of secular variations. Di †erence proÐles were calculated by subtracting a composite theoretical photospheric spectrum from the observed spectrum.The analysis of the Ha di †erence proÐles demonstrates that the accretion structures in Algol binaries have four basic morphological types : (1) double-peaked emission systems in which the accretion structure is a transient or classical accretion disk ; (2) single-peaked emission systems in which the accreted gas was found along the trajectory of the gas stream and also between the two stars in an accretion annulus ; (3) alternating single-and double-peaked emission systems, which can change between a single-peaked and a double-peaked type within an orbital cycle ; and (4) weak spectrum systems in which there was little evidence of any accretion structure since the di †erence spectra are weak at all phases. The Ðrst two types are the dominant morphologies. The Ðrst type can be interpreted physically as a disklike distribution, while the second is a gas streamÈlike distribution.The most common type in short-period Algols with 2.7 days \ P \ 4.5 days is a predominantly singlepeaked emission feature in the Ha di †erence proÐles (Type 2). This feature is redshifted during the phase interval / D 0.15È0.45 and blueshifted from / D 0.55È0.85. This single-peaked emission is often composed of two closely spaced emission peaks where one peak is at the Ha rest wavelength. The other peak is blueshifted at / D 0.65, where the line of sight is along the length of the approaching gas stream. Systems which display this morphology include RZ Cas, RW Tau, TW Dra, b Per, TX UMa, S Equ, and RS Vul. The orbital variation of the Ha observed proÐles of HR 1099 was similar to that seen in the di †erence spectra of this group and suggests that chromospheric emission may play a signiÐcant role in these binaries. A less common morphological type in the group of short-period Algols was a widely separated double-peaked disk-like distribution (Type 1) where the gas is in a transient or classical accretion disk. All of the long-period systems (P [ 6 days) were f...

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Section: Rw T Aurimentioning

confidence: 81%

Section: Historical Backgroundmentioning

confidence: 99%

Section: Systems Studiedmentioning

confidence: 99%

Section: Rw T Aurimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Morphologies of Hα Accretion Regions in Algol Binaries

Richards

Albright

1999

ASTROPHYS J SUPPL S

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109

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2015

Pulsating Stars

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Cyclic light and period variations of the UV Leonis system

Manzoori

2012

Astron Nachr

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Solutions of the new standard V -light curves for the EA type binary UV Leo are obtained using the PHOEBE code (0.31a version). Absolute parameters of the stellar components were then determined, enabling them to be positioned on the absolute magnitude-color (l.e. MV vs. B − V ) isochrones diagram, based on which the age of the system is estimated to be > 4×10 9 yr. Also times of minima data ("O − C curve") have been analyzed. Apart from an almost sinusoidal variation with a period of 29.63 yr, which modulates the orbital period, and was attributed to a third body orbiting around the system, other cyclic variation in the orbital period and also brightness, with time scales of 24.25 and 22.77 yr were found, respectively. We associate this with a magnetic activity cycle newly reported here for UV Leo.

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Evidence of magnetic activity in short-period Algol binaries

Cited by 47 publications

References 0 publications

Morphologies of Hα Accretion Regions in Algol Binaries

Morphologies of Hα Accretion Regions in Algol Binaries

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Cyclic light and period variations of the UV Leonis system

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