ISSN 2309-5539 (online)
Published by The VS-COMPAS Project © 2011-2014
Hrodna, 230005, Belarus

Variable Stars Observer Bulletin is all about variable stars science. It's made by amateurs and for amateurs. Here simplified contemporary data about different aspects of variable stars research is published. The bulletin is scheduled for six issues per year.

September-October 2013 (#2)

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Contents

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The FU Orionis phenomenon by Ivan Adamin

FU Orionis stars are pre-main-sequence eruptive variables which make up a small class of young low-mass stars appear to be a stage in the development of T Tauri stars. They gradually brighten by up to six magnitudes over several months, during which time matter is ejected, then remain almost steady or slowly decline by a magnitude or two over years. All known FU Ori stars (commonly known as fuors) are associated with reflection nebulae. The article gives a brief description of this kind of objects.
Read more >>

NSVS 5860878 = Dauban V 171: a new Mira variable in Cygnus
by Ivan Adamin, Siarhey Hadon

We present details of a new Mira variable in the constellation of Cygnus. The variability of the NSVS 5860878 source was detected in January of 2012 by Ivan Adamin, based on photometric data from the Northern Sky Variability Survey, as a part of data mining project, the VS-COMPAS. Lately, by the time the star's data was finally analyzed in 2013, the object was identified as the Dauban V171 in the VSX catalog, with no period and classification specified. Thus, a revision with actual data was submitted.
Read more >>

Twenty New W Ursae Majoris-type Eclipsing Binaries from the Catalina Sky Survey
by Stefan Hummerich, Klaus Bernhard, Gregor Srdoc

A short overview of eclipsing binary stars and their traditional classification scheme is given, which concentrates on W Ursae Majoris (WUMa)-type systems. Details for 20 new WUMa systems are presented, along with a preliminary model of the totally eclipsing system GSC 03090-00153, which was computed using Binary Maker 3. Read more >>

MISCellaneous variables revision: new periods and classification for 10 MISC records in the VSX database by Siarhey Hadon, Ivan Adamin

Updated periods and variability class for ten MISC records from the International Variable Star Index (VSX) database are presented. Initially, photometric variability of mentioned sources was determined using the fully automated algorithm (Pojmanski, 2002) and photometric data published by the All Sky Automated Survey (ASAS). Later, the results of Machine-learned ASAS Classification (Richards et al., 2012) became available. Own software is used for candidates selection, found a set of records for which periods can be improved considerably. Here the first portion of results is published along with the elements available for the selected sources from the mentioned research programs. Read more >>

Carbon in the sky: a few remarkable carbon stars by Ivan Adamin

A carbon star is a late type star similar to a red giant whose atmosphere contains more carbon than oxygen. The two elements combine in the outer layers of the star, forming carbon monoxide, which consumes all the oxygen in the atmosphere. These usually deep-red stars are good objects to look at. Here is the list of the most interesting and bright carbon stars published for northern observers.
Read more >>

Nova Delphini 2013: a naked-eye visible flare in northern skies
by Andrey Prokopovich

On August 14, 2013 a new bright star (6.3m) was detected in the constellation of Delphinus on the frames taken by Koichi Itagaki (Yamagata, Japan). Later it was assigned a status of Nova Delphini 2013 and became the brightest nova visible to a naked eye since Nova Scorpii 2007 (which reached magnitude 3.9 on February 17, 2007). Read more >>

Twelve new High-Amplitude Delta Scuti variables from the NSVS and CRTS surveys
by Ivan Adamin, Andrey Prokopovich, Alexandr Ditkovsky, Valery Tsehmeystrenko, Siarhey Hadon

As a part of VS-COMPAS data-mining program, here are twelve new pulsating High-Amplitude Delta Scuti variables presented. The research result on these objects is submitted to the VSX catalog for the first time by the VS-COMPAS team members. Photometric data from publicly available surveys (primarily, from the NSVS and CRTS) was used as a source for light curves. Read more >>

The "Heavenly Owl" observatory: seeing above the Black Sea waterfront by Valery Tsehmeystrenko

Just two decades ago one had to put quite a lot of efforts to build a quality light curve for a variable star. It was required even more to discover a new one, dealing with lots of frames taken during a night, then printed and compared. Nowadays, variable stars observers are in a privileged situation: there many ways of making a discovering process easier and more fun. Sure, you need some devices, but the variety of choice and affordability is like never before. In this article Valery Tsehmeystrenko from Odessa is going to share his experience in variable stars observation and analysis. Read more >>

Want to contribute an article? Feel free to contact us at:
http://www.vs-compas.belastro.net/bulletin-contribute

or please simply drop an email to [ivan dot adamin at gmail dot com]