January 2017
16 people attended this meeting on a cold night in January!
Financials: Dec 1 beginning balance 2117.94
Renewal dues 148.33.
One new student member 10.00
Ending balance 2276.27.
We are still accepting dues money!
New business—
Tulsa Central library (across from courthouse) grand opening of remodeling in March:
Jerry has been contacted by Peggy Walker, a Tulsa educator who is very involved in STEM and with the Broken Arrow Sidewalk Astronomers, and who attended the Galileo exhibit opening at the Schusterman library that we participated in, to see if we might be participating in this event which will take place March 7-9. This would be an evening (or at least, an after-school hours) event. We discussed what we might be able to do—at the Schusterman event we had an indoor exhibit of scopes and binoculars on tripods as well as some solar filter scopes set up in the courtyard. Fran Stallings also had a very successful story presentation for the children. We also brought our BAS handouts and star charts.
This upcoming event would be attended by 30-80 children (who must be accompanied by an adult) ages 5-12. We decided we would participate and Denise offered to contact Fran to see if she might be available to do something. We have to let Betty know whether or not we want to participate by Jan. 12.
Star party in January:
Jerry mentioned having a star party at Wah-Shah-She in January (as winter viewing is always good!). We decided to keep an eye on the weather and targeted first choice (weather permitting) Sat, Jan 21 and 2nd choice Sat, Jan 28. Jerry will have Steve call Wah-Shah-She to set this up on both dates (then we can cancel one later).
OK Mozart presentation:
Denise suggested looking into an indoor showcase event (possibly a reprise of the 20X20 presentations we did last April since they are already prepared), ideally on the Saturday of OKM (June 10). This might work out better than trying to do a star party out at Wah-Shah-She as we set up last year but then had to cancel the OKM part of it (and just do a party for us, which was very successful) because few OKM people signed up because they had to pay for bus transportation and they weren’t sure about the weather. Another possibility might be to have a star party in the grassy area in front of the Community Center on one of the nights there is an OKM performance inside the BCC. Similar to what we did last July and attracted some Pokemon players.
Preparation for the August total solar eclipse:
We discussed various kinds of solar glasses and possibly making solar filters. We might buy a bunch of solar glasses in bulk. Craig had seen a wrap-around kind on Amazon. Binocular filters would also be needed.
Daryl’s latest astronomy images:
Comet 45P taken Jan. 2. 20-second exposure; comet was low in the west.
This month’s main presentation—Globular Star Clusters by Daryl Doughty:
What are they?
Where are they?
When did they form?
How do they behave?
Globular clusters are large clusters of stars that have a well defined globular (spherical) shape as opposed to open star clusters which do not. (A good example of an open star cluster is the Pleiades.)
The stars in a globular cluster (and also an open cluster) form at about the same time.
A globular cluster can have several hundred thousand stars. The Omega Centauri globular cluster has millions of stars. A typical cluster might be 100 light years in diameter and 20000-30000 light years away from us. The distance between individual stars in a cluster might be a 10th of a light year.
Globular clusters that are part of the Milky Way galaxy are distributed around the middle of the galaxy; our Sun is to the left of center if you look at our galaxy along a horizontal axis from left to right.
The universe started forming 13.8 billion years ago.
The Omega Centauri globular cluster formed 11.3 billion years ago.
The Milky Way started forming about 8.8 billion years ago.
Our Sun formed 4.5 billion years ago.
The stars in globular clusters were in the first generation of stars that formed. An indicator of this is that globular clusters have low-metallic stars in them; at the time they formed, the only atoms were hydrogen and helium. The stars in globular clusters do not have heavy elements. This also meant that no planetary systems could form in them.
Some globular clusters may have black holes.
The stars in a globular cluster move together. For example, globular cluster Mayall II orbits the Andromeda galaxy (M31); it is perhaps a remnant of an elliptical galaxy passing through M31.
Daryl discussed overall star formation including red supergiants and blue stragglers—which are seen in globular clusters--with the aid of the Hertzsprung-Russell star formation chart. Blue stragglers may form through stellar cannibalism (one star envelops a smaller one) or stellar collision (two stars merge).
Daryl showed a large number of excellent globular cluster images, most of which he took himself; most of the others were taken by the Hubble.
Examples he showed included--
Omega Centauri. This is the most prominent globular cluster but not visible in Bartlesville—you would have to go to Galveston to see it; it’s a southern hemisphere cluster.
M38 in Auriga
NGC1987 in Auriga
M22 in Sagittarius (including the core taken by the Hubble)
M13 in Hercules
M192 in Hercules
47 Tucanea
NGC6362 in Ara
Good information source: www.eso.org (European Southern Observatory)
Free globular cluster download: www.globularclusters.org