Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: NEA: They are Close and Still Out There
Organization: Travelers in The Night
Link : 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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Transcript:
217-How CLose
My team the Catalina Sky Survey takes four images of the same place in the sky spaced out over 45 minutes or so. A typical image contains tens of thousands of stars, scores of main belt asteroids, and perhaps a couple of Earth approaching asteroids. Our software picks out the moving objects, identifies those of the half a million or so that we know, and presents the unknown ones to the human at the telescope for further action. Most of the potential Earth approaching asteroid candidates that the computer identifies are noise glitches, cosmic rays, or other types of electronic ghosts. A few have a shape and motion which makes them appear to be real. After follow up observations later that night the observer at the telescope posts the observations on a public web page at the Minor Planet Center. Telescopes around the world track the new object until its path in the sky is determined.
Recently I used this process to discover an object now named 2015 YV1. When I first spotted it, this 250 foot diameter space rock was 11.6 million miles from us and was moving away at almost 13 miles per second. An object of this size enters the Earth’s atmosphere every few thousand years producing an air burst equivalent to 16 million tons of TNT. Not to worry, 2015 YV1’s 2.5 year orbital path around our Sun will never bring it closer than about 1/4 the distance to the moon from the surface of planet Earth.
218-Still Out-There
My Catalina Sky Survey team mate Carson Fuls has discovered an object which bears watching. At the beginning of a long winter’s night of observing with a Schmidt telescope on Mt. Bigelow, Arizona, Carson came across a fast moving point of light in the night sky. He checked to make sure that it is a real object by observing it again a few hours later. After posting his observations on a public website at the IAU Minor Planet Center this new Earth approaching asteroid candidate was tracked by telescopes in Arizona, Japan, Italy, France, Texas, Hungary, and the Czech Republic. These data enabled the scientists at the Minor Planet Center to identify it as a potentially hazardous asteroid, calculate its orbit around the Sun, estimate its size, and give it the name 2015 YY9.
Carson’s new space rock, 2015 YY9 is about 480 feet in diameter, orbits the Sun once every two and a half years, and can make close approaches to Venus, Earth, our Moon, and Mars.
Fortunately 2015 YY9’s current orbit never allows it to come closer than about 3/4 the Moon’s distance from us. An asteroid of this size strikes the Earth every 16,000 years or so producing an air burst three times greater than the largest hydrogen bomb ever exploded and a crater a mile and a half in diameter.
Carson’s discovery alerts asteroid hunters to the fact that large dangerous unknown asteroids are still out there.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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Title: Travelers in the Night Digest: NEA: They are Close and Still Out There