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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353 – Backwards
Using the University of Arizona’s Large Binocular Telescope atop Mt. Graham in southern Arizona, Dr. Paul Wiegert of Western University in Canada, led a team of astronomers who have determined that a 2 mile diameter object bucks the solar system traffic by traveling in a direction backwards to all of the planets. In their March 30, 2017 article in the journal Nature, these astronomers confirm that 2015 BZ509, travels about Jupiter on a path in a direction opposite to nearly every other member of our solar system. Amazingly it has avoided a collision with Jupiter by using the giant planet’s gravity to maintain a path that has been stable for a million years or so. This astounding trick is performed as 2015 BZ509 passes once inside and once outside of Jupiter’s orbit as they both travel about the Sun. The resulting effect of Jupiter’s timely gravitational pulls on this small asteroid are exactly right to keep it from having a collision or from being ejected from the solar system.
How 2015 BZ509 got on such a strange path remains a mystery. Perhaps it is the icy core of a retrograde comet which was captured by Jupiter with possibility a little help from Saturn. So far 2015 BZ509 does not show any cometary activity. This may be because it is too far from the Sun’s warmth to have generated a coma and a tail although more distant comets have produced them. A spectrum, the pattern of colors it reflects from the Sun, could provide clues about its chemical composition and physical state.
354 – Returnee
On May 5, 2014 when I discovered 2014 JO25 with the Catalina Sky Survey’s 60 inch telescope on Mt. Lemmon, Arizona it was the brightest, fastest asteroid I had ever seen. In April of 2017, 2014 JO25 returned to come within 1.1 million miles of us at 21 mi/s. This rare, very close approach by an asteroid, of 2014 JO25’s size allowed scientists at NASA’s Goldstone Solar System Radar in California and the National Science Foundation’s Arecibo Observatory in Puerto Rico to obtain radar images of it. Amazingly these images showed that what we had observed as a solitary moving point of light and had assumed to be a single asteroid is actually two asteroids in contact with each other. This tight pair rotates about a common center of gravity about every 5 hours which in turn orbits the Sun in about three years. 41 days before its encounter with Earth, this tight pair was closer to the Sun than the planet Mercury.
It is possible that 2014 JO25 is the burned out nucleus of a comet which has lost its ice and gases during multiple close approaches to our Sun. The RADAR images of 2014 JO25 look very much like the nucleus of Comet 67P which was imaged close up by the Rosetta orbiter and visited by the Philae lander. 2014 JO25 is not likely to come so close again for hundreds of years and so its chemical composition is likely to remain a mystery.
For Travelers in the Night this is Dr. Al Grauer.
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365 Days of Astronomy
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