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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329 – Near Neighbor
My Catalina Sky Survey teammate Carson Fuls was using the new hundred million pixel camera on our team’s Schmidt telescope located on Mt. Bigelow, Arizona, when he discovered 2017 AG13. It passes near the Earth’s orbit twice a year on its own 345 day path around the Sun. When Carson spotted it, 9 lunar distances from him it was heading in our direction at about nine and a half miles per second. Three days later it came to less than two times the distance the Moon’s distance from us. Carson’s new space rock, 2017 AG13’s orbit, can bring it to less than 2,000 miles from the surface of our planet. It will not come near the Earth again until 2091 and will not strike the Earth in the foreseeable future. 2017 AG13 is slightly larger than the small asteroid which exploded over Chelyabinsk Russia, creating a sonic boom that injured nearly 1,500 people in February of 2013. If it had been on an impact trajectory, Carson’s early discovery, would have given humans the time to calculate where it would hit and thus be able to put out a warning for people in the affected area to stay away from doors and windows. Less than three weeks later Carson was using the same equipment when he discovered another small space rock, 2017 BH30, which came to a bit more than an Earth’s circumference from our home planet.
Carson’s recent discoveries illustrate the fact that asteroid hunters now have the capability to detect small space rocks before they make a close approach to Earth.
330 – Comet Johnson
Humans have recorded the passage of Halley’s comet since at least 240BC, as it has appeared in our sky every 75 to 76 years. Halley’s comet returns regularly because its orbit around the Sun is a closed elliptical path.
Comet C2/2015 V2 Johnson was discovered by my Catalina Sky Survey teammate Jess Johnson on November 3, 2015. It travels on a hyperbolic path around the Sun which is highly inclined to the plane where the planets and most of the asteroids travel. Jess’s comet’s path takes it from deep space into the inner solar system slightly further from the Sun than the planet Mars. Although it will not get closer to the Earth than about 75 million miles it may out gas enough material to make it visible to the naked eye. Observers in the northern hemisphere will have their best chance to view Comet Johnson in April and May of 2017 while those south of the equator will be able to observe it until early 2018.
Jess’s Comet will come closest to the Sun in June of 2017 and then be slung into deep space by the Sun’s Gravity. In February of 2037 Jess’s comet will be further than Pluto’s average distance to the Sun and be invisible to human telescopes as it moves in the direction a star 417 light years away in the constellation of Eridanus. It will take more than 12 million years to get to the vicinity of that distant star.
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365 Days of Astronomy
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