December 2013

No guests; 20 people in attendance

Treasurer’s report:

Beginning balance Nov. 1 $124.07

6 renewals at $110.00 total

Ending balance $1351.07

Also had 10 more renewals during the meeting

Wesleyan Christian School Astronomy night

Jan 9

Bring portable telescope @ 6 pm

Hope to have 6-8 telescopes

Bartlesville Symphony Orchestra fundraiser:

March 8

Want to have as many telescopes and members as can come. If you go (at least if you bring a telescope) you get a chili supper for free!

Next meeting Jan 6—Virgil Reese will discuss the latest in telescopes

February meeting—Mike Malone will present on radio astronomy

Program director—we need one!!

Carroll Ritchie handed over club publicity to Denise Gregg.

Current astronomy—report from Daryl:

• Sunspots in November; we are projected to be heading into a Monder Minimum period , a 50-70 yr period with less sunspot activity. The Earth will cool off.

• December—best part of sky with the “winter stars”; more prominent constellations. Dec 15—Jupiter in Gemini

• Comet Ison—broke up passing around the sun

Updates from Virgil—

• Astronomers are creating a catalog of 44 million stars and galaxies. This will cover 35% of the sky and use data going back to 1949. Will be publicly viewable on the internet.

• 0.6% of stars change brightness by quite a large amount over the course of a human lifetime.

• Gamma Ray GRB130427A will be very bright April 27. 3.6 billion light years away

• He showed picture from Hubble telescope of stellar jet in Carina Nebula

• Meteorite that hit Russia in January—he showed a picture of the hole in the ice it made. The meteorite exploded 28 miles high and people got severe burns from the brightness alone

• China is launching a moon rover and India is sending their first probe to Mars. So far the UK, US and Russia have gone to Mars.

Main presentation—Comets by Karen Cruce

Comet = “Wearing long hair”; from the Latin word comita

Comets have been observed for millennia; until the 16th century they were considered to be bad omens.

Comets are made of gas, dust, ice and rocks.

The nucleus is made of rock dust with water ice, frozen gases like carbon dioxide, carbon monoxide, methane, ammonia, formaldehyde , cyanide, ethanol and ethane—organic compounds. They may also have more complex molecules like amino acids.

The coma is a very thin atmosphere, 90% water and the rest dust. The coma starts to appear 3-4 AU from the sun.

Once a comet passes Mars, the coma goes into a tail, pushed by solar winds. There are actually 2 tails, one of dust, and another of gas that points away from the sun. Tails can extend 1 AU or more from the nucleus. (One AU, or astronomical unit, is the distance from the earth to the sun.)

Tails of comets create meteor showers, such as the Perseids and Leonids.

There are several types of comets:

Short-period or periodic—these originate in the Kuiper Belt, not the Oort cloud. The Kuiper Belt is 4.6 billion miles from the sun. Such comets are elliptical in orbit with a period of less than 200 years. They orbit in the same direction as other planets.

Main-belt—these originate in the asteroid belt and have a fairly circular orbit.

Long-period—these originate in the Oort cloud, which is a bubble around the solar system, located 4.6 trillion miles from the sun. These comets’ orbital periods range from 200 years to millions of years. They are slung inward by the pull of stars.

Single-apparition comets—not bound by the sun; leave our solar system after 1 pass. They will come within 850,000 miles of the sun; most crash or melt. Comet Ison is one of these.

Exo-comets—Outside our solar system; they orbit their stars.

Comets can be ejected from the solar system; their volatiles can be exhausted; they can break up or collide with other objects, such as one that hit Jupiter in 1994. Prior to the 16th century, comets were named by year. Starting with Halley’s comet, and until the early 20th century, they were named after the person who calculated their orbit unless they were single-apparition comets, in which case they were named by the year they are discovered. Beginning early in the 20th century they are named by the discoverer.

In 2014 the European Space Agency will launch a probe to land on comet Churyumor-Gerasimento.

Comet Ison was discovered by a Russian astronomer and named after the International Scientific Optical Network. When first discovered, it was traveling at 40,00 mph. Two weeks ago it was traveling at 150000 mph and at the time of slingshot around the sun, 820000 mph. Eight NASA satellite cameras were watching it.

Comet Lovejoy may be visible before dawn in the northeast in early/mid December.

In closing, "comets are like cats; they both have tails and they do what they like”.