Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: Dead Comet & Jupiter’s Comet
Organization: Travelers in The Night
Link : Travelers in the Night
Description: Today’s 2 topics:
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A potentially hazardous dead comet makes a close approach to Earth.
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The giant planet Jupiter has its own family of comets orbiting our Sun.
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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Transcript:
211-Dead Comet
A potentially hazardous asteroid made a close approach to our Moon and then to the Earth late in 2015. 2015 TB145 as it is now called, had come near humans six times between 1920 and 2015 but had gone unnoticed as it zipped through the night skies. On the 2015 close approach to us, the Pan-STARRS group in Hawaii found it heading towards the Sun at a speed of 23 miles/second.
On its 2015 close approach, 2015 TB145 was imaged by the RADAR at Goldstone, the Green Bank Telescope,and the Arecibo Observatory. These data show that this interesting object is about 2,000 feet in diameter and rotates about once every 5 hours. Dr. Vishnu Reddy a research scientist at the Planetary Science Institute in Tucson, Arizona said “We found that the object reflects about six percent of the light it receives from the sun”. Dr. Reddy continued “That is similar to fresh asphalt, and while here on Earth we think that is pretty dark, it is brighter than a typical comet which reflects only 3 to 5 percent of the light. Since 2015 TB145 reflects about half the light one would expect to obtain from a typical asteroid but we don’t observe the gas cloud of an active comet we are led to the conclusion that 2015 TB145 is a dead comet.
214-Jupiter’s Comet
End of podcast:
365 Days of Astronomy
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