14 DAY TRIAL // Astronomers in Canada announce the discovery of a new, interesting phenomenon at the heart of Wolf-Rayet stars. They say that the study which came at these conclusions was carried out using the MOST (Microvariability and Oscillations of STars) microsatellite, the country's only space telescope.
Wolf-Rayet stars are peculiar because they display broad emission bands in on otherwise continuous spectrum. This class of object was named after famed astronomers Charles Wolf and Georges Rayet.
The two discovered the first three stars in this group back in 1867, using the Paris Observatory's 40-centimeter Foucault telescope. While analyzing objects in the constellation Cygnus, they discovered the unusual stars HD191765, HD192103 and HD192641.
The new series of observations was carried out by experts at the University of Montreal, together with scientists at the Centre de Recherche en Astrophysique du Quebec (CRAQ). The Center is a collaboration between Universite Laval, the University of Montreal and the McGill University.
In the new research, MOST was aimed right at the heart of the Wolf-Rayet star CV Serpentis. Experts were surprised to discover a never-before-seen change in the stellar object's mass-loss rate.
It's also important to note here that CV Serpentis is a 30-day binary system. Astronomers also noticed variations in the depth of its atmospheric eclipses, which is something that no one was expecting to see.
WR stars are most interesting after they finish burning their hydrogen supplies, and start operating on helium. At that time, they begin to release massive amounts of carbon through its stellar winds. These objects are then called WC stars.
The formation of carbon atoms – which are released in varying amounts at any given time – requires high pressure and temperatures, experts propose. “One key case is undoubtedly the sporadic dust-producing WC star in CV Serpentis,” the team reveals.
“MOST was recently used to monitor [the object] twice (2009 and 2010), revealing remarkable changes in the depths of the atmospheric eclipse that occurs every time the hot companion’s light is absorbed as it passes through the inner dense WC wind.” the astronomers go on to say.
“The remarkable, unprecedented 70% change in the WC mass-loss rate might be connected to dust formation,” Universe Today quote the investigators as saying.
They add that future studies – conducted with larger, more complex telescopes – could shed more light into the nature of this mystery.