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Photometry of symbiotic stars. XI. EG And, Z And, BF Cyg, CH Cyg, CI Cyg, V1329 Cyg, TX CVn, AG Dra, RW Hya, AR Pav, AG Peg, AX Per, QW Sge, IV Vir and the LMXB V934 Her
We present new photometric observations of EG And, Z And, BF Cyg, CHCyg, CI Cyg, V1329 Cyg, TX CVn, AG Dra, RW Hya, AG Peg, AX Per, IV Virand the peculiar M giant V934 Her, which were made in the standardJohnson UBV(R) system. QW Sge was measured in the Kron-Cousin B, V,RC, IC system and for AR Pav we present its newvisual estimates. The current issue gathers observations of theseobjects to December 2003. The main results can be summarized as follows:EG And: The primary minimum in the U light curve (LC) occurred at theend of 2002. A 0.2 -- 0.3 mag brightening in U was detected in theautumn of 2003. Z And: At around August 2002 we detected for the firsttime a minimum, which is due to eclipse of the active object by the redgiant. Measurements from 2003.3 are close to those of a quiescent phase.BF Cyg: In February 2003 a short-term flare developed in the LC. Adifference in the depth of recent minima was detected. CH Cyg: This starwas in a quiescent phase at a rather bright state. A shallow minimumoccurred at JD 2 452 730, close to the position of the inferiorconjunction of the giant in the inner binary of the triple-star model ofCH Cyg. CI Cyg: Our observations cover the descending branch of a broadminimum. TX CVn: At/around the beginning of 2003 the star entered abright stage containing a minimum at JD 2 452 660. AG Dra: Newobservations revealed two eruptions, which peaked in October 2002 and2003 at 9.3 in U. AR Pav: Our new visual estimates showed atransient disappearance of a wave-like modulation in the star'sbrightness between the minima at epochs E = 66 and E = 68 and itsreappearance. AG Peg: Our measurements from the end of 2001 showedrather complex profile of the LC. RW Hya: Observations follow behaviourof the wave-like variability of quiet symbiotics. AX Per: In May 2003 a0.5 mag flare was detected following a rapid decrease of the light to aminimum. QW Sge: CCD observations in B, V, RC, ICbands cover a period from 1994.5 to 2003.5. An increase in the star'sbrightness by about 1 mag was observed in all passbands in 1997. Lesspronounced brightening was detected in 1999/2000. V934 Her: Ourobservations did not show any larger variation in the optical as areaction to its X-ray activity.
| A photometric and spectroscopic study of the eclipsing symbiotic binary AX Persei
We analysed photometric and spectroscopic optical observations of theeclipsing symbiotic binary AX Persei. For the first time, we present anddiscuss its historical, 1887-1999, photographic/B-band and visual lightcurve (LC). The red giant in AX Per losses mass via the wind at a rateof dot M = 7.4+/- 1.7 10-7 Msun yr-1.The terminal velocity of the wind is vinfty = 32 +/- 6 kms-1. We estimated an effective radius of the Hii nebuladuring the post-outburst stage (to JD 2450000) to be of Rn =192 +/- 25 Rsun and its average electron concentration ~ne = (2.9 - 3.6) +/- 0.7 109 cm-3 forthe electron temperature Te = 1-1.5 104 K. The[Oiii] nebula in AX Per is rather dense, having the electronconcentration ne([Oiii])~ 3 107 cm-3for Te = 1-1.5 104 K. Spectroscopic observationsmade in the middle of the 1992.8 and 1994.7 eclipses showed that asignificant part of flux emitted in the Hi, Heii and nebular [Oiii]lines originates in the vicinity of the hot component. Transition of AXPer to its nebular phase occurred at/around JD 2450000. A small ~ 0.6mag brightening at that time and consequently ery broad wave-likevariation in the LC developed. This event was caused by dilution of ashell around the hot star, during which about of 1.5 1050particles ( ~ 1.3 10-7 Msun) were injected intothe ionized region. Tables~2 and~3 are only available in electronic format the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) orvia http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/367/199
| Photometry of symbiotic stars. IX. TX CVn, CH Cyg, AX Per and AR Pav
We present new photometric observations of TX CVn, CH Cyg, AX Per and ARPav. The main results can be summarized as follows: TX CVn: Thehistorical 1893-2000 photographic/B-band light curve (LC) is presentedfor the first time. From 1892 to ~1920, the star was quiet, but thenentered a series of outbursts peaking in 1920, 1945, 1952 and 1962. From~1988 till the present time, TX Cvn has gradually declined. CH Cyg: Ourobservations cover an active phase, which began in May 1998. At thebeginning of June 1999 the star's brightness in the U band rapidlydecreased due to an eclipse of the active inner binary (the symbioticpair) by a cool giant in the outer orbit. AX Per: The historical1887-2000 photographic/B-band LC is summarized here for the first time.It is characterized by long-lasting periods of quiescence with thesuperposition of a few bright stages lasting about 1.5 orbital cycles.Our photoelectric U,B,V observations revealed a drastic change in the LCprofile, which occurred after JD 2 450 000 (1995.8). A small 0.6 magflare at that time and consequently very broad wave-like variation inthe LC developed. This event was caused by the dilution of a shellaround the hot star. AR Pav: Our observations show that the recentactive phase, which began in 1985.7 is over. During the activity, AR Pavdeveloped a complex wave-like variation at the level of ~1.5 mag in thevisual band. The transition to a quiet phase was rapid -- the wave-likevariation disappeared.
| Photometric study of the eclipsing binary EG CEP
New photoelectric B and V observations of EG Cep were taken and 11 newminima times were determined. They confirm the long-term increase of theorbital period. The light-curve analysis shows that the system issemi-detached. Mass transfer from the less to the more massive componentis responsible for the observed orbital period increase. Variations inthe transferred matter projected onto the surface of the components areresponsible for the colour dependent variable shift of the minima. Thiseffect, more pronounced in the secondary minima, explains also thedisagreement of the limb-darkening coefficient of the secondarycomponent with the theoretical value.
| On the nature of the outburst stage in the symbiotic binary AX Persei
We present photometric observations of the symbiotic binary AX Perduring the ourburst and post-outburst stages. This system contains a hotlow mass subdwarf which increases its radius due to thermonuclearburning and fills up its critical surface. A fraction of this material,of the order of 10-5 to 10-4 solar mass/yr istransferred onto the red giant, which is inside its Roche lobe, duringthe outburst. The observed increase of the star's brightness is causedmainly by collision of impacted matter with the red giant surface. Thisevent causes the wave-like variation of the AX Per light curve duringthe outburst with an amplitude of 2 mag in the optical UBV region bydiffering visibility of the collisional emission region in differentorbital phases of the binary. UBV light curves during the primaryminimum correspond to the total eclipse of the hot component by the coolcomponent. Detailed analysis gives the basic parameters of the binary:Rcool = 102 +/- 3 solar radius, Rhot = 36 +/- 3solar radius, orbit inclination i = 90 deg +/- 6 deg, luminositiesLhot = 340 (d/2.5 kpc)2 solar luminosity, upperlimit of the red giant luminosity Lg = 1800 (d/2.5kpc)2 solar luminosity, and the luminosity of the wave-likevariable light at the maximum Lvmax approximatelyequal to 1300 (d/2.5 kpc)2 solar luminosity. During thepost-outburst period the UBV primary minima indicated a smaller radiusand a higher temperature for the hot component. The suggested modeldisagrees with the accretion disk-powered model for AX Per.
| New Ephemeris of the Eclipsing Symbiotic Star AX Per
Not Available
| Photometry of symbiotic stars - an international campaign.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1991CoSka..21..303H&db_key=AST
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Osservazione e dati astrometrici
| Costellazione: | Cassiopea |
| Ascensione retta: | 01h37m25.07s |
| Declinazione: | +55°04'14.9" |
| Magnitudine apparente: | 7.475 |
| Distanza: | 333.333 parsec |
| Moto proprio RA: | 8.9 |
| Moto proprio Dec: | 3 |
| B-T magnitude: | 8.689 |
| V-T magnitude: | 7.576 |
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