IRAS 19135+3937: An SRd variable as interacting binary surrounded by a circumbinary disc

Semi-regular (SR) variables are not a homogeneous class and their variability is often explained due to pulsations and/or binarity. This study focuses on IRAS 19135+3937, an SRd variable with an infra-red excess indicative of a dusty disc. A time-series of high-resolution spectra, UBV photometry as well as a very accurate light curve obtained by the Kepler satellite, allowed us to study the object in unprecedented detail. We discovered it to be a binary with a period of 127 days. The primary has a low surface gravity and an atmosphere depleted in refractory elements. This combination of properties unambiguously places IRAS 19135+3937 in the subclass of post-Asymptotic Giant Branch stars with dusty discs. We show that the light variations in this object can not be due to pulsations, but are likely caused by the obscuration of the primary by the circumbinary disc during orbital motion. Furthermore, we argue that the double-peaked Fe emission lines provide evidence for the existence of a gaseous circumbinary Keplerian disc inside the dusty disc. A secondary set of absorption lines has been detected near light minimum, which we attribute to the reflected spectrum of the primary on the disc wall, which segregates due to the different Doppler shift. This corroborates the recent finding that reflection in the optical by this type of discs is very efficient. The system also shows a variable Halpha profile indicating a collimated outflow originating around the companion. IRAS 19135+3937 thus encompasses all the major emergent trends about evolved disc systems, that will eventually help to place these objects in the evolutionary context.Comment: Accepted to MNRA

Predictive value of global longitudinal strain and geometry of left ventricle in patients with noncompaction cardiomyopathy

Aim. To assess the prognostic role of a decrease in longitudinal strain and an increase in the left ventricular sphericity index as predictors of NYHA class III heart failure (HF) progression, requiring hospitalization in a cohort of patients with noncompaction cardiomyopathy (NCM) in combination with dilated cardiomyopathy (DCM).Material and methods. We examined 90 patients with a combination of NCM and DCM aged 18 to 72 years (median age, 41 years; men — 73; women — 17), who, in addition to conventional echocardiographic and magnetic resonance imaging (MRI) characteristics, were studied for two-dimensional strain and global longitudinal strain (GLS) parameters and left ventricular sphericity index (SI) using cardiac MRI. The endpoints included NYHA class III HF progression, requiring hospitalization.Results. During the follow-up period (median follow-up, 36 (6; 152) months) in 59 of 90 (65,5%) patients with NCM in combination with DCM, symptoms progressed to NYHA class III HF, requiring hospitalization. Multivariate analysis showed following independent risk factors for HF-related hospitalization: a decrease in GLS <10% (hazard ratio (HR), 5,1; 95% confidence interval (CI), 1,6-16,7, p<0,007) and an increase in SI >0,5 (HR, 9,0; 95% CI, 2,2-37,8, p<0,003) .The 3-year event-free survival rate for patients with one risk factor (GLS, %<10 and SI <0,5; GLS, %>10 and SI >0,5) was 79,2±16,9% and 64,4±24,6%, respectively, while for the group with two risk factors (GLS, %<10 and SI>0,5) — 12,3%.Conclusion. Global longitudinal strain characteristics according to 2D Strain echocardiography and SI according to cardiac MRI are associated with adverse events in NCM and DCM combination and can be used to identify patients with a high risk of HF progression to NYHA class III, requiring hospitalization

Variability of Hot Supergiant IRAS 19336-0400 in the Early Phase of its Planetary Nebula Ionization

We present photoelectric and spectral observations of a hot candidate proto-planetary nebula - early B-type supergiant with emission lines in spectrum - IRAS 19336-0400. The light and color curves display fast irregular brightness variations with maximum amplitudes Delta V=0.30 mag, Delta B=0.35 mag, Delta U=0.40 mag and color-brightness correlations. By the variability characteristics IRAS 19336-0400 appears similar to other hot proto-planetary nebulae. Based on low-resolution spectra in the range lambda 4000-7500 A we have derived absolute intensities of the emission lines H_alpha, H_beta, H_gamma, [SII], [NII], physical conditions in gaseous nebula: n_e=10^4 cm^{-3}, T_e=7000 \pm 1000 K. The emission line H_alpha, H_beta equivalent widths are found to be considerably variable and related to light changes. By UBV-photometry and spectroscopy the color excess has been estimated: E_{B-V}=0.50-0.54. Joint photometric and spectral data analysis allows us to assume that the star variability is caused by stellar wind variations.Comment: 11 pages, 6 figures, 2 tables, accepted for publication in Pis'ma Astron. Zh. (Astronomy Letters

Pulsations and Long-Term Light Variability of Three Candidates to Protoplanetary Nebulae

We present new photometric data and analysis of the long-duration UBV photoelectric observations for three candidates to protoplanetary objects - F-supergiants with IR-excesses located at large galactic latitudes, IRAS 18095+2704, IRAS 19386+0155, and IRAS 19500-1709. All three stars have revealed quasiperiodic low-amplitude variabilities caused by pulsations observed against the long-term trends of brightnesses. For IRAS 18095+2704=V887 Her we have found a pulsation period of 109 days and a linear trend of brightness under the constant colours if being averaged over the year timescale. The light curve of IRAS 19386+0155=V1648 Aql over 2000-2008 can be approximated by a wave with a main period of 102 days which is modulated by close frequency, with a period of 98 days, that results in brightness oscillations with a variable amplitude. V1648 Aql has also shown synchronous reddening together with a persistent rise of brightness in the V-band. IRAS 19500-1709=V5112 Sgr experiences irregular pulsations with the periods of 39 and 47 days. The long-term component of the variability of V5112 Sgr may be related to the binary character of this star.Comment: 11 pages, 6 figures, accepted for publication in Pis'ma Astron. Z