SZ Psc Research Articles

Features of the Wave-Like Distortion in Some Rs CVn Binaries

One of the outstanding features of RS CVn-type binaries is the changing shape of the so called “wave-like distortion” or “photometric wave” (PW) and its phase migration on the light curve (LC). Here we present a preliminary analysis of the observations of the following objects: CQ Aur, RU Cnc, VV Mon and SZ Psc. For each system we have derived the amplitude and phase of the PW maximum and its migration rate.

Light curves of SZ Piscium for 1977 and 1978

We present a relatively completeV-band light curve of SZ Psc for 1978 and a partial light curve for 1977. From the 1978 light curve we derive a new time of primary minimum, JD⊙2443823.674±0.001, and a Russell-model solution,i=75°.8±0°.1,r h =0.096±0.003,r c =0.351±0.001, andL h =0.253±0.002. The hotter component of this system is a F5-8 main-sequence star, the cooler component a K3-4 star well above the main sequence. The system is detached with the larger component filling only 82% of its Roche lobe. The distortion wave in this RS CVn-type binary seems not to migrate regularly as do those in many other such systems, but rather seems to change phase and amplitude more erratically. Between 1977 and 1978 its phase stayed practically constant while its amplitude decreased by a factor of three. We discuss the implications of this behavior for the spot model of RS CVn-type activity. We find that the traditional comparison star for SZ Psc, HD 219018, is very likely a constant star contrary to a recent suggestion that it is variable. Its brightness and colors,V=7.705, (B-V)=0.628, and (V-I) c =0.688, are those of a G2V star.

ON THE NATURE OF H ALF OUTBURSTS IN THE RS CVN BINARY SZ PSC.

ABSTRACT An H-alpha emission episode on the RS CVn binary SZ Psc was observed in 1979. These observations are compared with a recently reported 1978 outburst, and both data are discussed and interpreted in terms of the surface phenomena or star-spot model. Bopp (1981) had attributed the 1978 H-alpha outburst as due to a mass-transfer or mass-loss event caused by the cooler primary expanding on a short-time scale and overfilling its Roche lobe. This interpretation appeared to be inconsistent with the surface phenomena model. Evidence is presented which supports the bizarre behavior of the H-alpha emission line as being due to the existence of a disk fed by flare-like eruptions. Bopp's 1978 observations can also be explained in terms of such a model, only more material would be involved in that event, since its H-alpha emission is about twice as strong.

A remarkable H-alpha outburst in the RS CVn binary SZ PISCIUM - A transient mass-transfer event

The very unusual spectroscopic behavior of the RS CVn binary SZ Psc (K1IV + F8V; P = 3.97 days) is described. For much of the time the Ha line in the K star appears as a weak absorption feature, presumably partially filled by chromospheric emission. The Hα equivalent width ordinarily shows small variations that may be adequately explained by stellar surface activity. During a single month in 1978, however, the appearance and behavior of the Hα feature were bizarre. Over the course of a few nights the line profile changed from the expected weak absorption feature to a broad (∼300 km s<SUP>-1</SUP>) double-peaked emission. This emission profile persisted, weakening slowly, for several weeks. Velocity measures indicate the K star was the source of the emission. Such an Ha outburst, with its unusual profile and temporal behavior, has never been seen in other, more intensively observed RS CVn systems. An explanation in the strict context of surface phenomena does not appear feasible. Instead, we propose that the emission is circumstellar in origin, produced from a ring or shell of gas around the primary K component. We examine the possibility that this Hα outburst may have signaled a transient mass-transfer event in this barely detached system.

Radio Flare Activity of RS CVn Stars

For several years, a systematic program to observe RS CVn and similar binaries has been undertaken with the 46-m telescope of the Algonquin Radio Observatory. A number of large radio outbursts at 2.8 cm wavelength has been found from HR 1099, AR Lac, SZ Psc, UX Ari, and HR 5110. In several cases, simultaneous, or nearly simultaneous, observations of these stars were made by cooperating observers at (other) radio, optical, UV, and X-ray wavelengths. It is now clearly established that the mechanism responsible for the cm-wavelength radio emission is nonthermal gyrosynchrotron radiation in a volume whose characteristic dimension is comparable with the binary star separation. More generally, a semi-quantitative model for the radio flare activity of these stars seems to be possible using greatly scaled-up analogues of solar magnetic activity.

The Star Spot Model and the Observations of SZ Piscium

Details of photometric observations during the totalities of the primary and secondary minima of SZ Psc are analysed in the light of the “star spot model” for RS CVn type binaries. Presence of scatter during the totality of primary minimum and its absence during the totality of secondary minimum of SZ Psc provide evidence towards one of the assumptions of the model,i.e. the spot activity confines to one of the hemispheres of the cooler star.

Starspots as the cause of the intrinsic light variations in RS Canum Venaticorum type stars

A starspot model is proposed to interpret the light curves of three RS CVn type binary systems. Two of the systems are RS CVn and SZ Psc, which are detached, while the third system, RT Lac, is semidetached. Solar activity and the surface activity of the RS CVn type stars are compared. It is found that the spot model permits the detailed fitting of both the out-of-eclipse complications and the distorted shapes of the secondary eclipses in the light curves of these stars.

Survey of H-alpha emission in V711 Tau /HR 1099/ and related CA II emission binaries

view Abstract Citations (88) References (20) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Survey of Halpha emission in V711 Tau (HR 1099) and related Ca II emission binaries. Bopp, B. W. ; Talcott, J. C. Abstract We report the results of a survey of V7 11 Tau (HR 1099), UX Ari, and 26 other RS CVn and Ca II emission binaries for Ha emission. A total of six stars show Ha continuously or sporadically in emission while the remainder show pure absorption profiles at 1-A resolution. Observations of UX Ari during 19761977 indicate that the equivalent width (EW) of the emission is correlated with the orbital phase with maximum strength occurring near = O .6. At this same epoch, Hall found the phase of photometric minimum to be O .8 in late 1976 moving to 0 .7 in early 1977. Another RS CVn binary, V71 1 Tau, has been observed for three years and intensively during two major radio flares. Though Ha is enhanced by a factor of two to three during radio outbursts, the EW in HR 1099 is not correlated with orbital phase and no long-term variations are apparent. Four stars show sporadic emission: HD 86590, HK Lac, AR Lac, and SZ Psc. Publication: The Astronomical Journal Pub Date: December 1978 DOI: 10.1086/112355 Bibcode: 1978AJ.....83.1517B Keywords: Binary Stars; Calcium; Emission Spectra; H Alpha Line; K Lines; Radio Stars; Stellar Spectra; Line Spectra; Stellar Spectrophotometry; Astrophysics; Emission Lines:RS CVn Binaries; H Alpha:RS CVn Binaries full text sources ADS | data products SIMBAD (29)

The radio luminosities and spectra of RS CVn binaries

view Abstract Citations (85) References (14) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The radio luminosities and spectra of RS CVn binaries. Owen, F. N. ; Gibson, D. M. Abstract Interferometric and VLA data on 26 RS CVn systems are combined with previously published radio data in order to evaluate the radio luminosity and spectral characteristics of the RS CVn binaries. Five surveys of these systems are reviewed, along with the present status of the systems SZ Psc and HD 224085 and a probable detection of TY Pyx. The luminosity function and median spectral index are determined for six RS CVn radio binaries, and it is suggested that radio emission from these systems at centimeter wavelengths is commonly of the order of a few times 10 to the 16th power erg/s per Hz. It is concluded that Z Her is underluminous and RT Lac is overluminous with respect to the other RS CVn binaries, that a certain 'threshold' luminosity may exist for flare activity in these systems, and that the radio emission is likely to originate in a region whose size is characteristic of a binary system rather than an individual star. Publication: The Astronomical Journal Pub Date: December 1978 DOI: 10.1086/112349 Bibcode: 1978AJ.....83.1488O Keywords: Binary Stars; Radio Emission; Stellar Luminosity; Stellar Spectra; Microwave Emission; Radio Astronomy; Radio Stars; Stellar Radiation; Astronomy; Radio Radiation:RS CVn Binaries; RS CVn Binaries:Spectra full text sources ADS | data products SIMBAD (29)