MINUTES OF THE 432ND, FEBRUARY 2008, MEETING
PRESENT
Kevin Thurston (Chairman), Geoff Flood, Tony Aremia, Graham Sinagola,
Nick Odom, Peter Baugh, Norman Thurstan, Chris Suddick, Paul Clark, Geoff Walton, Elizabeth Clark, Paul Brierley, Colin Eaves, Joe Holland, Colin Bowler,
Mark Crossley, Richard Bullock, John Tipping, John Thompson.
The Chairman welcomed everyone to the 432nd meeting of the Society.
John Thompson from Macclesfield AS gave a talk on “The Life and Death of Stars”
Ninety-five percent of the Earth’s energy comes from the Sun - but don’t worry this will continue one way and another for some 5 billion years.
Spiral Galaxies, such as M51, are the region of star formation which takes place in the spiral arms where dust (carbon) Hydrogen and Hydrogen ions etc are irradiated with UV from hot young stars to form the embryonic stars. Very often these embryonic stars are surrounded by dense clouds of dust and thus cannot be seen.
We see many clouds of dust, particularly in nebulae, often being blown about by solar winds along with gaseous globules which give ongoing possibilities.
Star formation is a violent process and often leads to bi-polar jets blasting out from the proto star - more energy in space.
Planets, orbiting around stars are often discovered via a Doppler effect and some 271 extra solar planets have been discovered to date (there will be more now!)
We were told that Red, Blue and Green stars really are coloured (although the green ones really should be white)
HR diagram gives the absolute brightness of stars with the hottest stars with most energy being brightest, giving out more light.
Equally stars with bigger mass burn out more quickly i.e. higher mass quicker evolution.
The energy in stars such as the Sun is produced by nuclear fusion reactions which create heavier elements. Starting with Hydrogen – the simplest element, Helium, is first produced.
When the Hydrogen in the core runs out however, the core shrinks until its temperature and pressure increases enough to fuse Helium and create Carbon. At this point the star begins to bloat and becomes a Red Giant, with the reactions at the centre of the core quickly evolving to create heavier and heavier elements so that seen in section the core resembles an onion with different reactions at different depths. Once the core starts producing Iron the reactions quickly come to an end and in the last stages of evolution stars begin pulsating throw off their outer layers.
The final state of the star is to become a white dwarf.
Equally stars with bigger mass burn out more quickly i.e. higher mass, quicker evolution and a different ending.
Very massive stars are “doomed to boom” and go supernova.
More energy is required than can be produced by fusion to create elements more dense than Iron and they can only be created when a massive star explodes as a supernova and heavy elements are thrown out into space so that a death releases elements for a birth.
The remnants of the boom may become a Neutron Star or in the case of the biggest stars a Black Hole where the remnant is so dense that nothing gets out, not even light.
First discovered in 1783 by John Michel, Black Holes were named as such only in 1969. All galaxies are thought to have at least 1 Black Hole.
So, there is a process; Gas Cloud – Red Super Giant – Super Nova – Black Hole/Neutron Star.
And we……are just stardust.
Kevin thanked John who had spoken so eloquently, with great slides and video, to the enlightenment of the audience.
There was no formal business to be dealt with and Kevin closed the meeting with information that at the next meeting there will be a talk by Dave Ogden with an update on Messier Objects.
Kevin Thurston (Chairman), Geoff Flood, Tony Aremia, Graham Sinagola,
Nick Odom, Peter Baugh, Norman Thurstan, Chris Suddick, Paul Clark, Geoff Walton, Elizabeth Clark, Paul Brierley, Colin Eaves, Joe Holland, Colin Bowler,
Mark Crossley, Richard Bullock, John Tipping, John Thompson.
The Chairman welcomed everyone to the 432nd meeting of the Society.
John Thompson from Macclesfield AS gave a talk on “The Life and Death of Stars”
Ninety-five percent of the Earth’s energy comes from the Sun - but don’t worry this will continue one way and another for some 5 billion years.
Spiral Galaxies, such as M51, are the region of star formation which takes place in the spiral arms where dust (carbon) Hydrogen and Hydrogen ions etc are irradiated with UV from hot young stars to form the embryonic stars. Very often these embryonic stars are surrounded by dense clouds of dust and thus cannot be seen.
We see many clouds of dust, particularly in nebulae, often being blown about by solar winds along with gaseous globules which give ongoing possibilities.
Star formation is a violent process and often leads to bi-polar jets blasting out from the proto star - more energy in space.
Planets, orbiting around stars are often discovered via a Doppler effect and some 271 extra solar planets have been discovered to date (there will be more now!)
We were told that Red, Blue and Green stars really are coloured (although the green ones really should be white)
HR diagram gives the absolute brightness of stars with the hottest stars with most energy being brightest, giving out more light.
Equally stars with bigger mass burn out more quickly i.e. higher mass quicker evolution.
The energy in stars such as the Sun is produced by nuclear fusion reactions which create heavier elements. Starting with Hydrogen – the simplest element, Helium, is first produced.
When the Hydrogen in the core runs out however, the core shrinks until its temperature and pressure increases enough to fuse Helium and create Carbon. At this point the star begins to bloat and becomes a Red Giant, with the reactions at the centre of the core quickly evolving to create heavier and heavier elements so that seen in section the core resembles an onion with different reactions at different depths. Once the core starts producing Iron the reactions quickly come to an end and in the last stages of evolution stars begin pulsating throw off their outer layers.
The final state of the star is to become a white dwarf.
Equally stars with bigger mass burn out more quickly i.e. higher mass, quicker evolution and a different ending.
Very massive stars are “doomed to boom” and go supernova.
More energy is required than can be produced by fusion to create elements more dense than Iron and they can only be created when a massive star explodes as a supernova and heavy elements are thrown out into space so that a death releases elements for a birth.
The remnants of the boom may become a Neutron Star or in the case of the biggest stars a Black Hole where the remnant is so dense that nothing gets out, not even light.
First discovered in 1783 by John Michel, Black Holes were named as such only in 1969. All galaxies are thought to have at least 1 Black Hole.
So, there is a process; Gas Cloud – Red Super Giant – Super Nova – Black Hole/Neutron Star.
And we……are just stardust.
Kevin thanked John who had spoken so eloquently, with great slides and video, to the enlightenment of the audience.
There was no formal business to be dealt with and Kevin closed the meeting with information that at the next meeting there will be a talk by Dave Ogden with an update on Messier Objects.
posted by Geoff Flood at 11:59 AM
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