Organization: Travelers in The Night
Description: Today’s 2 topics:
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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403 – Double Comet
In November of 2006, University of Arizona’s Spacewatch astronomers on Kitt Peak discovered a faint moving point of light in the night sky which appeared to be a garden variety main belt asteroid orbiting the Sun between Mars and Jupiter. The Minor Planet Center calculated it’s orbit and gave it the name 2006 VW139. Five years later when it again moved closest to the Sun the Pan-STARRS group in Hawaii discovered that 2006 VW139 is surrounded by a gas cloud like a comet and it was given a comet designation, 288P. My Catalina Sky Survey teammate Steve Larson is a member of the team of astronomers who use the Hubble Space Telescope to observe asteroids which have comet like burps. Observations by the Hubble Space Telescope between August 2016 and January 2017 clearly show 288P to be two similar, mile diameter, asteroids orbiting each other about 60 miles apart, surrounded by a gas cloud, as they move about the Sun. The Hubble team estimates that about 5,000 years ago this strange object was formed when a rapidly rotating comet nucleus came apart into two large pieces. It’s gas cloud is likely to come from volatile ices like carbon dioxide and water vapor which were liberated by solar heating. Objects like this one are very interesting since they may have had a role in bringing water to a bone dry Earth in the early days of our solar system.
404 – Jess’s Find
Recently my Catalina Sky Survey teammate Jess Johnson discovered a large new member of the group of sneaky asteroids called Atens. The geometry of an Aten’s orbit can allow it to approach the Earth with it’s dark side pointing in our direction making it difficult to discover.
Jess’s new object was then observed at more than 10 observatories around the world. Scientists at the Minor Planet Center used these data to calculate the details of it’s 353 day orbital path about Sun, estimate it’s size to be about 0.4 of a mile in diameter, and give it the name 2017 SN14. An asteroid the size of Jess’s object strikes the Earth once every several hundred thousand years or so creating a crater 6 miles in diameter and producing devastation over thousands of square miles of the Earth’s surface. Fortunately 2017 SN14 ‘s path never brings it closer than 20.5 times the Moon’s distance from us. The most famous and most potentially dangerous Aten cousin of 2017 SN14 is Apophis. For a brief period in 2004 it appeared that Apophis might impact the Earth in 2029 releasing 13 times the energy of the largest hydrogen bomb ever exploded. Subsequent data confirms that the luckiest Friday the 13th in human history will occur in 2029 when Apophis misses Earth by less than the distance to our communication satellites.
For Travelers in the Night this is Dr. Al Grauer.
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365 Days of Astronomy
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