We carried out a V RCIC photometric monitoring of StHα 55, and in addition we obtained low resolution absolute spectro-photometry and high resolution Echelle spectroscopy. Our data show that StHα 55 is a carbon Mira, pulsating with a 395 day period, with =13.1 mean brightness and ∆V=2.8 mag amplitude. It suffers from a low reddening (EB−V =0.15), lies at a distance of 5 kpc from the Sun and...

With the advent of surveys generating multi-epoch photometry and the discovery of large numbers of variable stars, the classification of these stars has to be automatic. We have developed such a classification procedure for about 1700 stars from the variable star catalogue of ASAS 1-2 (All Sky Automated Survey, Pojmański 2000) by selecting the periodic ones and by applying an unsupervised Bayes...

This paper presents statistics of the line-doubling phenomenon in a sample of 81 long-period variable (LPV) stars of various periods, spectral types and brightness ranges. The set of observations consists of 315 highresolution optical spectra collected with the spectrograph ELODIE at the Haute-Provence Observatory, during 27 observing nights at one-month intervals and spanning two years. When c...

Reliable prediction of stellar diameters, particularly angular diameters, is a useful and necessary tool for the increasing number of milliarcsecond resolution studies being carried out in the astronomical community. A new and accurate technique of predicting angular sizes is presented for main sequence stars, giant and supergiant stars, and for more evolved sources such as carbon stars and Mir...

In this paper we review the various high precision methods that are now available to determine the distance to NGC 5128. These methods include: Cepheids, TRGB (tip of the red giant branch), PNLF (planetary nebula luminosity function), SBF (surface brightness fluctuations), and Long Period Variable (LPV) Mira stars. From an evaluation of these methods and their uncertainties, we derive a best-es...

We present circular polarization measurements of circumstellar H2O masers around 2 Mira variables and 4 supergaint stars. Both an LTE and non-LTE method are used to analyze the circular polarization and total intensity spectra and to obtain the magnetic field strength. The non-LTE method is found to be able to reproduce the observations best. Using this, we find fields from a few hundred milliG...

A globular cluster distance scale based on Hipparcos parallaxes of subdwarfs has been used to derive estimates of MK for cluster Miras, including one in the SMC globular cluster NGC121. These lead to a zero-point of the Mira infrared period-luminosity relation, PL(K), in good agreement with that derived from Hipparcos parallaxes of nearby field Miras. The mean of these two estimates together wi...

We present angular size measurements of 22 oxygen-richMira variable stars. These data are part of a longterm observational program using the Infrared Optical Telescope Array to characterize the observable behavior of these stars. Complementing the infrared angular size measurements, values for variable star phase, spectral type, bolometric flux, and distance were established for stars in the sa...