Dec 1st: RADAR Telescopes Pair Up to Image Near-Earth Asteroid & A Whopper Or A Comet

By on December 1, 2019 in
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Podcaster: Dr. Al Grauer

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Title: Travelers in the Night Eps.  55 & 56: RADAR Telescopes Pair Up to Image Near-Earth Asteroid & A Whopper Or A Comet

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Organization: Travelers in The Night

Link : Travelers in the Night ; @Nmcanopus

Description: Today’s 2 topics:

  • NASA’s RADAR telescopes at Goldstone, California and the Arecibo Observatory in Puerto Rico were used to obtain images of 2014 HQ124.
  • If 2014 LJ21 is an asteroid, its brightness suggests that it is about 1 and a quarter miles in diameter. On the other hand if 2014 LJ21 is a comet, we still know its path accurately, but don’t have a good way to estimate its size.

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:

41E55 – RADAR Telescopes Pair Up to Image Near-Earth Asteroid

Recently NASA’s NEOWISE space telescope discovered an asteroid which subsequently passed about 3 times the Moon’s distance from Earth. More than 100 followup observations were obtained by ground based telescopes all over the world and it was named 2014 HQ124.  These data prove that it will not be a threat to Earth till past the year 2200.  Using the NEOWISE infrared observations, NASA Astronomer, Dr. Amy Mainzer obtained a preliminary diameter of 1200 feet for this asteroid.

During 2014 HQ124’s recent approach to Earth, NASA RADAR telescopes at Goldstone, California and the Arecibo Observatory in Puerto Rico were used to obtain images over about a 4 1/2 hour period of time. 

The spectacular RADAR images show surface details on this asteroid  down to about 12 feet in diameter.  It is peanut shaped and may actually be two asteroids in contact with each other. This object has many interesting features including a very steep sided hill which can be clearly seen in the RADAR images.

2014 HQ124 is a Potentially Hazardous Asteroid which orbits the Sun every 9 and 1/2 months on a path which takes it near both Venus and Earth.

RADAR observations of asteroids and comets are an important way to measure an objects size, shape, and rate of spin.  The precise distance measurements they provide make it possible to predict an object’s path far into the future and thus determine if it is a risk to planet Earth. 

42E56- A Whopper Or A Comet

Ray Sanders  was observing with the NASA funded Catalina Sky Survey telescope on Mt. Bigelow, Arizona when he discovered a curious moving point of light in the night sky.  Over the next 72 hours this object was observed by more than a dozen observatories all around the world and given the name 2014 LJ21.  These data were used to find its path as it orbits the Sun every 5 years from near Mercury to out past Mars.

If 2014 LJ21 is an asteroid, its brightness suggests that it is about 1 and a quarter miles in diameter.  This estimate is based on the assumption that it reflects about 15% of the Sun light which strikes it. The impact of an asteroid this size would likely cause global climate change. 

On the other hand if 2014 LJ21 is a comet, we still know its path accurately, but don’t have a good way to estimate its size.

Either way, an impact with our home planet would not be a good thing. Fortunately, this object never comes closer than about 10 times the Earth-Moon distance from us.  We will need to keep track of it to make sure that it does not become on an impact trajectory with the Earth.

How can we tell the difference between an asteroid and a comet?  A large telescope could be used to divide the light up into its component colors to see which are present and which are missing.  These data would reveal its composition and identity.  Alternatively, a long exposure photograph might reveal some  “fuzz” around it and letting us know it is a comet.

In the meantime we will just have to wonder if it is a whopper or a comet.

For Travelers in the Night this is Dr. Al Grauer

End of podcast:

365 Days of Astronomy
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