Podcaster: Dr. Al Grauer


Title: Travelers in the Night Eps. 147E & 148E: Good News & ALMA Spots Juno

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s 2 topics:

  • Carson Fuls discovered 55 foot diameter 2015 LF.
  • “…the new ALMA images show the actual millimeter-wavelength light emitted by the asteroid,” said Todd Hunter of NRAO.

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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145E: Good News

Recently my NASA funded Catalina Sky Survey teammate Carson Fuls discovered an approaching asteroid about the same size as the one whose high altitude disintegration injured nearly 1500 people in Chelyabinsk Russia in February of 2013.  Fortunately this new one missed planet Earth.  There is more good news.  

Carson spotted this small space rock about 40 hours before its closest approach to planet Earth.  This means that if it had been on a collision path with our home planet we would have had time to warn people to seek shelter before it created a potentially destructive sonic boom in our atmosphere.

When Fuls discovered it this 55 foot diameter asteroid was about 150,000 miles from him and was traveling towards us a 10 miles/second.  Telescopes in Arizona, Australia, Romania, Italy, and France tracked it through the night sky.  The minor planet center used these observations to find its path and give it the name 2015 LF.  It orbits the Sun once every 3.5 years on a path that takes it from between Earth and Venus out to 80% of the way to the planet Jupiter. 

Unlike the Chelyabinsk Meteor which came at us from close to the direction of the Sun,  2015 LF approached planet Earth from a direction away from the Sun with most of its little full moon face pointing in our direction.  This is the most favorable situation for asteroid hunters to be able to detect an Earth approaching object.

146E: ALMA Spots Juno

Juno was found by German astronomer Karl L. Harding in 1804 who noticed that to the human eye it appeared to be a star like moving point of light in the night sky.  The light that Juno reflects suggests that it could be the source of stony meteorites called chondrites that we find on Earth. 

Scientists have long known that every object whose temperature is above absolute zero radiates a small glow.  On Earth we use this fact to construct night vision goggles and to do non invasive medical imaging of the human body. 

Up until October of 2014 our knowledge of Juno was based on the light this asteroid reflects from the Sun. That all changed when astronomers pointed the Atacama Large Millimeter/submillimeter Array at it. This powerful group of radio dishes which is nicknamed ALMA is located about 9,500 feet above sea level in the high dry desert of northern Chile.

“In contrast to optical telescopes, which capture the reflected light from the Sun, the new ALMA images show the actual millimeter-wavelength light emitted by the asteroid,” said Todd Hunter, an astronomer with the National Radio Astronomy Observatory.  Hunter continued stating “By using ALMA to image the thermal glow from asteroids like Juno and other bodies in our solar system, astronomers will be able to study their shape, composition, and surface properties.”

Juno will make a much closer approach to us in 2018.   At this range ALMA will be able to make images with the double the resolution of the previous ones.   Stay tuned.

For Travelers in the Night this is Dr. Al Grauer.

End of podcast:

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