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RASC St. John's Centre Monthly Meeting
November 14, 2001
Location: Chemistry/Physics Building, MUN
Time: 8:00 pm
Present: 26
1. Randy's Introduction. General introduction to the Centre and the RASC. Randy
mentioned we have a new brochure out now for new members. The date for next
month's meeting hasn't been worked out yet, we don't want it too close to
Christmas. Leonids. Introduction for Dr. Robert Garrison, Professor Emeritus of
Astronomy for the University of Toronto.
2. Some Bizarre Stars I Have Known. The Interpretation of Stellar Spectra. Dr.
Garrison began talking about the RASC, outlining how we now have 26 Centres and
over 4800 members. It is quite a task to keep track of all our members. He felt
that RASC membership is quite a bargain compared with other groups, especially
considering the publications.
Most of astronomy depends on the knowledge gained from studying spectra, in one
way or another. I will present his talk in outline format.
- The Cosmic Experiment.
- Classification philosophy.
- The romance has gone for many current students of astronomy.
- Space exploration is not for him: who cleans your visor when you sneeze?
- Survey --> discovery --> explore what makes it tick.
- Some things he has discovered: a pure helium star; brightest cataclysmic variable (People's CV at mag. 9.4); aluminium oxide in Mira variables; strong barium stars; Population II carbon stars: weak lines, strong CH, no CN.
- Indirect involvement in Supernova Shelton 1987A was fantastic (discovered at the U. of T. Southern Observatory).
- The David Dunlop Observatory is alive and well; much spectroscopic research can still be done in bright environments. Subtract background sky spectra from your data.
- In 1951 W.W. Morgan presented his results on galactic structure and mapped our location in the spiral arm. The result was the only standing ovation he has ever seen at an astronomical conference.
- Outline of stellar distance scale determination: parallax (hold up your finger), spectra, types of stars, distance scale.
- Work done on Galactic Halo metallicity gradient, solar-type G dwarf.
- NASA/NSF inventory of nearby stars: one part of the ORIGINS project. One result is that 18 Scorpii is now known to be a very close twin to the sun, more so than Alpha Centauri.
- Supernova 1987A. Originally, the theorists thought a blue supergiant shouldn't explode like that. Within a week they had alternate theories, as theorists do.
- Spectroscopy --> spectra --> red is cool, blue is hot (plumbers get it backward).
- Stellar specimens --> classification methods and philosophy --> Aristotle versus Plato.
- H-R diagram. Basic features, such as the Main Sequence.
- 10 parsec survey indicates about 5000, including things that are failed stars.
- The theoretical solar spectrum contains 17*10^6 lines, but these don't come near to all the lines observed.
- The Theoretician's Black Box and simplifying assumptions.
- Slides from Chile
- Worked with artist John Lomberg on galactic painting (galactic structure).
- Pictures: Andean Condor; desert fox; U of T Southern Observatory (now sold and moved).
3. Coffee Break.
4. What's Up Next Month. Jupiter. Saturn occultation.
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Please send any additions or corrections to:
David Bourgeois: mailto:dbourgeo@nl.rogers.com
Last updated on November 23, 2001
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