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Location: Chemistry/Physics Building, MUN
Time: 8:00 pm
Present: 21
Garry gave the usual introduction, followed by observations by members. Garry also showed the new national brochure which prominently features member Joe English on the cover.
We are still looking for ideas on a venue for International Astronomy Day. The date could also be shifted around as part of Astronomy Week, or we could have our own day.
Fred noted that some meeting announcements seem to be bouncing. Particularly if you are a member, you should have received meeting announcements. If not, let someone know on the executive.
Gary Case noted there may be another education session on April 25.
Randy Dodge noted that the new version of David Levy's book is available at Chapters.
A sign-up sheet for those interested in Butterpot observing was circulated.
Robert Babb passed around a handout on the sky over the next month or so. Robert touched on the planets, the Lyrids meteor shower on April 22 and the "Trawlerman" formation of the Moon and Venus. There are no comets right now, but a possible green comet in the southern hemisphere may develop over the next month into something visible to most amateurs. He finished on galaxies, deep sky objects, and talked about a project of photographing the moon with Venus.
Only Tim Caruk was brave enough to attempt last month's project, but no photos are available.
Garry asked members what kind of things would they want at meetings. Maybe members could talk about their interests, or activities/projects. Perhaps members know of someone else who could be a good speaker for a meeting. Our next meeting may be at the planetarium at the Marine Institute, depending upon speaker arrangements.
Fred noted there will be a seminar tomorrow in our room, open to the public, on string theory. Interested members are welcome.
Fred introduced our speaker, Dr. Steve Shorlin, who hails from Jeffries. Steve got his B.Sc. here at MUN, went on to a Masters at St. Mary's, and finished with a Ph.D. from the University of Western Ontario.
The talk will be about the magnetic field of stars on the "middle" (sort of) of the Main Sequence.
Steve explained the Main Sequence for beginners, and how stellar composition was determined with spectroscopy (emission and absorption lines).
Steve used some hands-on demos. We got to see how metals and other rare elements are distributed on the surface of these stars with a rotating basketball with popsicle sticks to mark the magnetic poles. Concentrations of elemental iron, say, could be found at particular marks on the ball, and rotate in or out of sight. Three horseshoe magnets and a rotating wire coil demonstrated how the electromagnetic and magnetic fields are related.
In this manner, electron flows in a star can give rise to magnetic fields. In "peculiar" stars, these fields don't seem to be like those seen in the solar dynamo, but are more regular and quiescent. Fossil fields from the time of stellar formation are believed in many cases to explain some of the observations. The ultimate explanation can be found in the field of Magneto-Hydrodynamics, and running lots of computer simulations to compare with reality.
Another demo involved two polarised pieces of glass, to explain how polarised light might be detected. The polarimeter is used to detect fields on the star and build up an overall picture of the magnetic field structure on the star. Steve went to Pic du Midi and used their polarimeter for 80 observations over 3 weeks to study various star's magnetic fields. His experience was not as civilised as Chris Stevenson's recent visit. At the end of his observing run he was stuck at the mountain top in a snow storm. He arrived days late at the airport expecting flight hassles, but ironically the same bad weather had cancelled his earlier flight, enabling him to reschedule. Steve showed us some pictures of his Pic du Midi experience, but there weren't too many outside shots thanks to the time of year.
The talk was followed by some questions.
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