Related papers: The evolution of the Mira variable R Hydrae
Context. Stars on the asymptotic giant branch (AGB) are long-period variables that present strong flux variations at almost all wavelengths, including the SiO maser lines. The periods of these variations are of 300-500 days in Mira-type…
The group of Mira-type and semi-regular variables with similar periodicity (multiperiodicty) is analyzed. They have periods of 230-260 days and 140-150 days and show intervals of periodical (Mira-type) variability with relatively high…
Evolution of stars with initial masses $M_\mathrm{ZAMS}=1.1M_\odot$, $1.3M_\odot$, $1.5M_\odot$ and relative mass abundances of metals $Z=0.006$ and 0.02 was computed from the main sequence up to the final AGB stage. Selected models of…
Low- and intermediate-mass stars go through a period of intense mass-loss at the end of their lives in a phase known as the asymptotic giant branch (AGB). During the AGB a significant fraction of their initial mass is expelled in a stellar…
We present a complete census of RR Lyrae stars in a halo field of the Andromeda galaxy. These deep observations, taken as part of a program to measure the star formation history in the halo, spanned a period of 41 days with sampling on a…
We derive the basic physical parameters of the field double-mode RR Lyrae star BS Com from its observed periods and the requirement of consistency between the pulsational and evolutionary constraints. By using the current solar-scaled…
For the ordinary classical nova QZ Aurigae (which erupted in 1964), we report 1317 magnitudes from 1912--2016, including four eclipses detected on archival photographic plates from long before the eruption. We have accurate and robust…
Aims. Our goal is to characterize the intermediate age, detached shell carbon star U Antliae morphologically and physically in order to study the mass-loss evolution after a possible thermal pulse. Methods. High spatial resolution ALMA…
We have carried out a new photometric V,Rc study of 12 protoplanetary nebulae, objects in the short-lived transition between the AGB and PN phases of stellar evolution. These had been the subjects of an earlier study, using data from…
Near-infrared, JHKL, photometry of 239 Galactic carbon-rich variable stars is presented and discussed. From these and published data the stars were classified as Mira or non-Mira variables and amplitudes and pulsation periods, ranging from…
For the first time connection between the pulsation and modulation properties of RR Lyrae stars has been detected. Based on the available data it is found that the possible range of the modulation frequencies, i.e, the possible maximum…
Evolutionary sequences of AGB stars with initial masses on the main sequence $M_\mathrm{ZAMS}=1.5M_\odot$, $2M_\odot$ and $3M_\odot$ were computed for the initial metallicity $Z=0.014$. Selected models of evolutionary sequences with…
MOST (Microvariability & Oscillations of STars) and ASAS (All Sky Automated Survey) observations have been used to characterize photometric variability of TW Hya on time scales from a fraction of a day to 7.5 weeks and from a few days to 8…
We report an observed accretion rate of $\dot M_1 = (3.86\pm0.60)\times 10^{-11}$ $M_{\odot}$yr$^{-1}$ for the white dwarf in the short-period, intermediate polar EX Hya. This result is based upon the accretion-induced $4\pi$-averaged…
Aims: We aim to perform the first long-term analysis of the system HS Hya. Methods: We performed an analysis of the long-term evolution of the light curves of the detached eclipsing system HS Hya. Collecting all available photometric data…
Four months of quasi-simultaneous spectroscopic and photometric observations were used to study the variations of the photometric light curve, the evolution of the chromospheric activity from the H$\alpha$ and H$\beta$ lines, and the…
In this work, a sample of luminous M-type giants in the Baade's Windows towards the inner Galactic Bulge is investigated in the near-infrared. The ISOGAL survey at 7 and 15 micron has given information concerning the mass-loss rates of…
The binary companion to the peculiar F supergiant HD 172481 is shown to be a Mira variable with a pulsation period of 312 days. Its characteristics are within the normal range found for solitary Miras of that period, although its pulsation…
Context. The post-main-sequence evolution of massive stars remains poorly understood, particularly for blue supergiants. These objects play a crucial role in the dynamical and chemical evolution of galaxies and exhibit pronounced…
As an eclipsing polar with 3.39 hrs orbital period, MN Hya was going through state change when we observed it during 2009-2016. 10 new mid-eclipse times, along with others obtained from literature, allow us to give a new ephemeris. The…