Recent photometry of symbiotic stars

Abstract

We present new photometric observations of 15 symbiotic stars covering their last orbital cycle(s) from 2003.9 to 2007.2. We obtained our data by both classical photoelectric and CCD photometry. Main results are: EG And brightened by ∼0.3 mag in U from 2003. A ∼0.5 mag deep primary minimum developed in the U light curve (LC) at the end of 2006. ZAnd continues its recent activity that began during the 2000 autumn. A new small outburst started in summer of 2004 with a peak U magnitude of ∼ 9.2. During the spring of 2006 the star entered a massive outburst. It reached its historical maximum at U ∼ 8.0 in 2006 July. AEAra erupted in 2006 February with Δmvis ∼ 1.2 mag. BF Cyg entered a new active stage in 2006 August. A brightness maximum (U ∼ 9.4) was measured during 2006 September. CH Cyg persists in a quiescent phase. During 2006 June–December a ∼ 2 mag decline in all colours was measured. CI Cyg started a new active phase during 2006 May–June. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Recent photometry of symbiotic stars

“…The photoelectric measurements were done in the UBV filters of the Johnson's photometric system with a 10 second integration time. Observations made at the Skalnaté Pleso observatory was described by Skopal et al (2004). At the Hvar observatory, classical photoelectric UBV observations were carried out by a single-channel photometer mounted in the Cassegrain focus of a 0.65-m reflector.…”

The symbiotic system CH Cygni: An analysis of the shocked nebulae at different epochs

“…During the last months it showed a ∼ 2mag decline in the optical bands (2006 June-December, Skopal et al 2007) and a most significant, anomalous, IR fading (Taranova & Shenavrin 2007). In April 2004, high-resolution optical data by Yoo (2006) detected double-peaked emission components for the Hα and Hβ profiles, with an interesting V/R <1, where V and R stand for the intensities of the blue and red wings, respectively.…”

“…Since the beginning of the 2000, CH Cyg persists in a quiescent phase at rather bright magnitude, despite a 2 mag decline in the U B V light curves during the 2006 June-December period (Skopal et al 2007). An apparently anomalous extreme IR fading has been recently pointed out by Taranova & Shenavrin (2007).…”

“…Taranova & Yudin 1988Munari et al 1996;Skopal et al 1996Skopal et al , 1997Skopal et al , 2000Skopal et al , 2002Skopal et al , 2004Skopal et al , 2007 have allowed to follow small changes in the emitting properties of CH Cyg, without leading to a substantial breakthrough.…”

“…11 we present the modelling of the UBV and JHKLM data presented by Skopal et al (2007) and Taranova & Shenavrin (2007), respectively. The models which best fit the slopes of the data are the combination of those used in previous epochs (see caption of Fig.…”