The Fifth Edition of the General Catalogue of Variable Stars:experiences in the constellation Centaurus

We have recently announced that the General Catalogue of Variable Stars enters the stage of its fifth, purely electronic edition （GCVS 5.1）. We have included 1408 variable stars in the constellation Centaurus in this new version, GCVS 5.1. Working on this revision, we applied current possibilities from data mining, suggested new variability types for many variable stars and found new light elements for a large number of periodic variables. This paper describes the work completed during the preparation of GCVS 5.1 for Centaurus and discusses in detail a number of the most astrophysically significant cases.

Preface: Modern studies of variable stars

In this Mini-Volume, seven papers written on the basis of talks selected from those presented at the scientific conference "Modern studies of variable stars," commemorating Prof. M. A. Svechnikov(1933–2011), are published. The conference covered a variety of variable-star topics; the papers in this Mini-Volume deal with close, mainly eclipsing, binaries, Herbig Be stars and stellar molecular masers, with an accent on stellar catalogs of different kinds. We briefly review the contents of these papers.

Preface: Stars and interstellar medium

This issue presents proceedings of the ＂Stars and Interstellar Medium＂ section of the All- Russian Astronomical Conference VAK-2017. Sixteen papers （selected from about 70 talks） cover dif- ferent problems related to stars, pulsars, interstellar gas and dust, and star formation. The preface briefly reviews these papers.

New variable stars from the photographic archive:semi-automated discoveries,attempts at automatic classification and the new field 104 Her

Using 172 plates taken with the 40-cm astrograph of the Sternberg Astronomical Institute （Lomonosov Moscow University） in 1976-1994 and digitized with a resolution of 2400dpi, we dis- covered and studied 275 new variable stars. We present the list of our new variables with all necessary information concerning their brightness variations. As in our earlier studies, the new discoveries show a rather large number of high-amplitude Delta Scuti variables, predicting that many stars of this type re- main not detected in the whole sky. We also performed automated classification of the newly discovered variable stars based on the Random Forest algorithm. The results of the automated classification were compared to traditional classification and showed that automated classification was possible even with noisy photographic data. However, further improvement of automated techniques is needed, which is especially important when considering the very large numbers of new discoveries expected from all-sky surveys.

GSC 4560–02157: a new long-period eclipsing cataclysmic variable star

We study the newly discovered variable star GSC 4560-02157. CCD photometry was performed in 2013-2014 at the Tien Shan Astronomical Observatory,and a spectrum was obtained with the 6-m telescope of the Special Astrophysical Observatory in June, 2014. GSC 4560-02157 is demonstrated to be an eclipsing variable star（P = 0.265359d）. All its flat-bottom primary minima are approximately at the same brightness level, but the star＇s out-of-eclipse brightness and brightness at secondary minima vary considerably（by up to 0.6m） from cycle to cycle. Moreover,there are short-term（time scale of 0.03-0.04 days） small-amplitude brightness variations out of eclipse. This behavior suggests a cataclysmic nature for the star, which is confirmed with a spectrum taken on 2014 June 5. The spectrum shows numerous emissions of the hydrogen Balmer series, He Ⅰ and He Ⅱ.