Urban Astronomy Inverness

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The formation of a young protostar following the collapse of a previously inert dust cloud

We had a great turnout for March’s Urban Astronomy session last week at the Sea Cadet’s Hall in Inverness.  The indoor presentation massively benefited from our new giant screen, expertly erected by Robbie (pictured below).  Here’s a selection of slides from my presentation on naked eye observing and the life of giant stars.

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Robbie putting the final touches to our new giant screen for indoor astronomy presentations and virtual sky guiding

Topics covered:

– Naked eye and binocular observing
– Satellites: Iridium Flares and ISS
– Colour, temperature and mass of stars
– The Hertzsprung-Russell diagram
– Protostar formation from dark nebulae
– Main sequence burning and final fate of stars
– White dwarfs, supernovae, neutron stars and black holes.

As ever there were some superb questions during and after the talk.  Stay tuned for upcoming events as myself and Caroline roll out the program.

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In the simplest terms stars behave like black body radiators with colour linked to their surface temperatures.

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The brightest stars in the night sky can be close – like Sirius – or giant stars very far away (eg. Betelgeuse, Rigel, Deneb).

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The HR diagram.  An elegant and reliable tool for describing the evolution of stars from main sequence burning into their final stages of life

Sirius Rising

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The dog star ‘Sirius’ is now high and visible in winter skies looking South. Draw a line down and left from Orion’s belt and you can’t miss the brightest star in the night sky.

Sirius means ‘scorching’ and was considered a second Sun of sorts to many ancient cultures. Its incredible brightness is due to its close proximity. At only 9 light years away it’s the 5th closest star system to our Sun and a fairly typical hydrogen fusing main sequence star likely to live a long stable life of several billion years.  This is in contrast to short lived giant stars like Rigel and Betelgeuse, which are very distant and appear bright  due to their bloated sizes and massive energy output.

Sirius
Procyon is sometimes mistaken for Sirius but it rises earlier, hence its name which means ‘before the dog’.  The Arabs told a tale linking Procyon and Sirius as two sisters, who became separated by a great river (the Milky Way) while searching for their missing brother.