Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps. 195E & 196E: Carbon Comets & Hot Lunation

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s two stroy:

  • Eric Christensen found Comet C/2006 W3 Christensen almost 10 years ago.
  • During the November 2015  “hot lunation” our team discovered 89 new close approachers.

Bio: Dr. Al Grauer is currently an observing member of the Catalina Sky Survey Team at the University of Arizona.  This group has discovered nearly half of the Earth approaching objects known to exist. He received a PhD in Physics in 1971 and has been an observational Astronomer for 43 years. He retired as a University Professor after 39 years of interacting with students. He has conducted research projects using telescopes in Arizona, Chile, Australia, Hawaii, Louisiana, and Georgia with funding from NSF and NASA.

He is noted as Co-discoverer of comet P/2010 TO20 Linear-Grauer, Discoverer of comet C/2009 U5 Grauer and has asteroid 18871 Grauer named for him.

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195E: Carbon Comets

When my Catalina Sky Survey team captain Eric Christensen found Comet C/2006 W3 Christensen almost 10 years ago it was approaching the orbit of Saturn on its way towards the inner solar system. Three years later it reached it’s closest point to our Sun.  Currently it is moving away from the Sun and is almost to the orbit of the planet Uranus.  It will not come back to near Earth again for another 2.5 million years. 

In an article in the Astrophysical Journal submitted in 2015, the analysis of the NASA  NEOWISE satellite observations of Comet C/2006 W3 Christensen reveal that it is outgassing vast quantities of carbon dioxide and carbon monoxide.  When these observations of Comet C/2006 W3 Christensen were obtained it had a dust cloud 2/3 of the diameter of the Sun.

 Dr. James Bauer lead author of the scientific paper tells us  “As they get closer to the sun, these comets seem to produce a prodigious amount of carbon dioxide”,  Bauer goes further saying  “Your average comet sampled by NEOWISE would expel enough carbon dioxide to provide the bubble power for thousands of cans of soda pop per second.”Currently there are more than 5,000 comets which have been discovered by humans out of the 50,000 or more which may exist. They represent samples of what may have been present when our solar system formed. It is interesting to speculate that the carbon in our bodies may have been brought to Earth long ago by comets like C/2006 W3 Christensen.

196E: Hot Lunation

My team the Catalina Sky Survey operates two telescopes in the Catalina Mountains near Tucson, Arizona 24 nights per month between full moons.  We call this period of time a lunation.   During the November 2015  “hot lunation” our team discovered 89 new close approachers.

This newly discovered group of Earth approaching objects is very diverse.  They range in size from 8 to 4700 feet in diameter. Half of them are less than 150 feet in diameter.  Nine of them can come closer than the Moon to planet Earth. One of them is about 25 feet in diameter and can come to within about an Earth’s circumference from us. 

The members of this group of 89 approach the Earth from various directions as they orbit the Sun.  Seven of them are called Atens since they cross the Earth’s orbit with periods of less than a year. 54 are called Apollo’s since they cross the Earth’s orbit and have an orbital period of greater than a year.  The remaining are called Amor’s since their orbit crosses that of Mars and comes close to ours but does not cross it.

The most dangerous one is 2015 WA2. It is about 650 feet in diameter and can come to within 11 Earth diameters of us.  There is no chance that it will impact Earth in the foreseeable future. One 2015 WA2’s size enters  Earth’s atmosphere every 36,000 years or so making a crater several miles in diameter.  We will need to keep track of 2015 WA2 in case its path is changed as it encounters other objects in space.

End of podcast:

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