New physical elements of HR 7428 and its H<i>α</i>behaviour

Marino, G.; Catalano, S.; Frasca, A.; Marilli, E.

doi:10.1051/0004-6361:20010823

Cited by 8 publications

(21 citation statements)

References 38 publications

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“…Richards & Albright 1999). Evidence for intersystem matter have been also recently reported by Marino et al (2001) for HR 7428, a long-period detached atypical RS CVn binary composed of a bright K giant and an A-type star.…”

Section: Hα Emission Profilessupporting

confidence: 58%

Hαspectroscopy and $\vec{BV}$ photometry of RT Lacertae

Frasca

Çakırlı²,

Catalano

et al. 2002

A&A

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Abstract. Contemporaneous spectroscopic and photometric BV observations of the RS CVn type eclipsing binary RT Lacertae were performed in summer 2000. The photometric observations were obtained at the Ege University Observatory, while the spectroscopic ones were carried out at Catania Astrophysical Observatory in the spectral range 5860-6700Å. We obtained a high quality radial velocity curve of the system that allowed us to give more accurate values of the orbital parameters. A steady decrease of the barycentric velocity from 1920 to 2000 has been pointed out and has been discussed in the context of a third body hypothesis. Through the subtraction of a "synthetic" spectrum, built up with spectra of inactive standard stars, we detected Hα excess emission which fills in the photospheric absorption profiles of both components. With the exception of a few spectra, taken close to the eclipses, in which some extra absorption or a faint double-peaked broad emission appears, there is no further evidence of circumstellar matter in this system, as suggested in previous works. The hotter and more massive star appears also as the more active at a chromospheric level, since it has a Hα flux about ten times greater than the companion, on average. Rotational modulation of the Hα emission has been detected in both stars. The hemisphere of the more massive star facing the observer at phase 0. p 75 appears brighter (in Hα) than that seen at phase 0. p 25, while for the less massive G9 IV star the maximum Hα emission is seen around phase 0. p 0-0. p 1. From the analysis of the contemporaneous light curve (Lanza et al. 2002), the more massive G5 IV star results to be more active than the companion at a photospheric level, in agreement with the chromospheric behaviour observed in Hα. In addition, the starspots of the G5 IV star are mainly located in the Hα brighter hemisphere, suggesting a close spatial association of spots and plages in this star. The G9 IV star displays instead the maximum Hα emission at the phase of maximum visibility of the smaller spotted area found from the light-curve analysis. The minimum Hα emission occurs when the more heavily spotted region is visible.

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Section: Hα Emission Profilessupporting

confidence: 58%

Hαspectroscopy and $\vec{BV}$ photometry of RT Lacertae

Frasca

Çakırlı²,

Catalano

et al. 2002

A&A

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“…Richards & Albright 1999). Evidence for inter-system matter, emitting and absorbing at Hα wavelengths, has been also recently reported by Marino et al (2001) for HR 7428, a long-period, detached atypical RS CVn binary composed of a bright K-type giant and an A-type star. Furthermore, extended, prominence-like structures producing extra-absorption at Hα wavelength have been detected in some eclipsing RS CVn systems by Hall & Ramsey (1992) and by Frasca et al (2000a).…”

Section: Analysis Of the Hα Linesupporting

confidence: 62%

H$\boldmath{\alpha}$ variations of the RS CVn type binary ER Vulpeculae

Çakırlı¹,

İbanoǧlu²,

Frasca³

et al. 2003

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Abstract. We present the results of spectroscopic observations of the active eclipsing binary ER Vul in the 5860-6700 Å spectral range carried out at the Catania Astrophysical Observatory. Accurate measurements of radial velocities by using the crosscorrelation technique have been made and a new orbital solution is given. All spectra display chromospheric emission which fills in the Hα absorption lines of both components. The equivalent width (EW) of the Hα emission has been measured by subtraction of a synthetic spectrum built up with spectra of inactive standard stars. The EW of total Hα emission, arisen from both components, shows a phase-dependent variation. It reaches its maximum value just before the primary eclipse. We were able to separate the contributions to the Hα emission from the individual components at phases far from the eclipses. We have found that the secondary, cooler component is the most active and its Hα residual emission shows the same trend as the total Hα emission, along orbital phase. This Hα equivalent width variation can be due to plage-like structures on the chromosphere of secondary star. In addition, a decrease of the Hα EW around the ingress phase of the primary eclipse is apparent.

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“…AR Lacertae consists of a G2 IV primary and a K0 IV secondary star, which are spin-orbit coupled with Send offprint requests to: I. Pagano, e-mail: ipa@sunct.ct.astro.it a 1.98 day period, and have a mass ratio M 1 /M 2 ∼ 0.89 (Marino et al 1998). The K star seems to be metaldeficient, but this is not the case for the G star (Naftilan & Drake 1977).…”

Section: Introductionmentioning

confidence: 99%

“…The absolute magnitudes M V are then derived by adopting the distance d = 42 pc measured by HIPPARCOS (Perryman et al 1997). The radii are computed from the product of the mean fractional radii given by Lanza et al (1998) (r G = 0.117, and r K = 0.303) and the semi-major axis given by Marino et al (1998) (d G−K = 8.9 R for orbital inclination i = 87…”

Section: Introductionmentioning

confidence: 99%

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Spectral imaging maps of AR Lacertae

Pagano

Rodonò

Linsky

et al. 2001

A&A

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Abstract. In October 1994 the RS CVn eclipsing binary AR Lacertae was monitored by IUE during two orbital cycles. We have used 59 low resolution spectra, acquired in the range 1150-1950Å, to derive light curves for emission lines formed at different temperatures between about 10 000 and 200 000 K and to study the flare signatures versus temperature of line formation. We have analyzed a sequence of 59 high resolution Mg ii k line profiles using multi-Gaussian fits (the spectral imaging technique) to derive information of the spatial structure of the chromospheres of both stars in the AR Lac system. We discuss the quiet chromospheric emission from both stars, and we show that enhanced Mg ii emission is present in extended structures corotating with the K0 IV star and close to the system center-of-mass. We also report on evidence for absorbing structures toward both the stars. This study of AR Lac used the new orbital elements of Marino et al. (1998) and spectra reduced and calibrated with NEWSIPS. A comparison between fluxes derived from the analyzed NEWSIPS spectra and from IUESIPS spectra is provided.

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New physical elements of HR 7428 and its Hαbehaviour

Cited by 8 publications

References 38 publications

Hαspectroscopy and $\vec{BV}$ photometry of RT Lacertae

Hαspectroscopy and $\vec{BV}$ photometry of RT Lacertae

H$\boldmath{\alpha}$ variations of the RS CVn type binary ER Vulpeculae

Spectral imaging maps of AR Lacertae

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