A binary star is a star system consisting of two (or more) stars orbiting around their common center of mass. We had cloudless skies over Longstanton for the first time this year, so I managed to have a quick look at a few binary star systems last January (despite the glare from the gibbous moon and bloody freezing cold). The first is Cor Caroli, which can be found in the crook of the Big Dipper's handle, just to its right, standing almost due east. The star is a true binary, consisting of two stars orbit each other (each orbit is estimated to take about 7,900 years). These two stars are designated Alpha-1 (the fainter of the two) and Alpha-2, and are thought to be about 650 Astronomical Units apart (that's 650 times the distance between the Earth and the Sun).
And here's a processed still image of the video:
A close-up of Cor Carioli. Cor Carioli (the heart of Charles) is named after Charles I of England, who was executed during the English Civil War in 1649. According to legend, this star brightened when his son, Charles II, return from exile on May 29, 1660. Cor Carioli is in fact a variable (it's brightness changes). The strong magnetic field of these stars are believed to produce starspots of enormous extent, which cause their brightness to vary considerably during their rotation.
We now come to Polaris below, so named due to the position of the star near the north celestial pole. Point a telescope at any other star and you will see it moving across your field of view, but point it at Polaris and it stays dead still. This made it a reliable beacon for early navigators. Polaris actually consists of one bright star - Polaris A - and two companion stars. The brighter of the two companions, Polaris B (the faint star on the left of the picture), is about 2000 Astronomical Units (AU) away from Polaris A (that's 2000 times the distance between the Earth and the Sun). Polaris A actually has another close companion star orbiting with 5 AU from the primary but it is too close to the primary star to be resolved visually.
Not everything that looks like a double is in fact a binary star system. Procyon below IS a binary star system, consisting of a white main sequence star Procyon A, and a faint white dwarf companion Procyon B. However, that faint star to the left is NOT Procyon B. The separation of Procyon A and B is 15.0 AUs - a little less than the distance between Uranus and the Sun - so Procyon B would be too faint and too close to the 'glare' of Procyon B to be observable on an 80mm scope. At a distance of 11.46 light-years away from earth, Procyon is one of our near neighbours.
And here's a processed still image of the video:
A close-up of Cor Carioli. Cor Carioli (the heart of Charles) is named after Charles I of England, who was executed during the English Civil War in 1649. According to legend, this star brightened when his son, Charles II, return from exile on May 29, 1660. Cor Carioli is in fact a variable (it's brightness changes). The strong magnetic field of these stars are believed to produce starspots of enormous extent, which cause their brightness to vary considerably during their rotation.
We now come to Polaris below, so named due to the position of the star near the north celestial pole. Point a telescope at any other star and you will see it moving across your field of view, but point it at Polaris and it stays dead still. This made it a reliable beacon for early navigators. Polaris actually consists of one bright star - Polaris A - and two companion stars. The brighter of the two companions, Polaris B (the faint star on the left of the picture), is about 2000 Astronomical Units (AU) away from Polaris A (that's 2000 times the distance between the Earth and the Sun). Polaris A actually has another close companion star orbiting with 5 AU from the primary but it is too close to the primary star to be resolved visually.
Not everything that looks like a double is in fact a binary star system. Procyon below IS a binary star system, consisting of a white main sequence star Procyon A, and a faint white dwarf companion Procyon B. However, that faint star to the left is NOT Procyon B. The separation of Procyon A and B is 15.0 AUs - a little less than the distance between Uranus and the Sun - so Procyon B would be too faint and too close to the 'glare' of Procyon B to be observable on an 80mm scope. At a distance of 11.46 light-years away from earth, Procyon is one of our near neighbours.
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