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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319 – Lost & Found
When asteroid hunters follow an object in the night sky for a few hours or a couple of days they are only able to observe a snippet or tracklet of the object’s hundreds to thousands of days long path around the Sun. If we only have a short sample of an orbit we loose precision to locate the object as the length of time since the last observation increases. It is thus possible to lose the knowledge of where to find a particular asteroid.
Recently my Catalina Sky Survey teammate Richard Kowalski came across a moving point of light in the night sky which initially the Minor Planet Center classified as an unknown object . For the next 70 hours telescopes in New Mexico, Arizona, Italy, England, France, South Africa, Chile, New Zealand, Germany, and Pennsylvania measured the object’s position in the sky and sent their observations to the Minor Planet Center. These data enabled scientists there to link to an object which had been discovered 15 years earlier, 2001 WF49.
In this way asteroid hunters were able to recover the ability to accurately predict the position of 2001 WF49, a 426 foot diameter object which orbits the Sun every 238 days on a path that has brought it near Earth nearly 50 times since 1900. 2001 WF49 comes much closer to Mercury than it does to Earth and must be made of rocky or metallic stuff to survive it’s relatively close approaches to the Sun. This might make 2001 WF9 a candidate for mining in the future as space colonists look for resources to build their homes and factories.
320 – WOW What a Ride
Riding the surface of the asteroid that my Catalina Sky Survey teammate Richard Kowalski recently discovered would be an incredible experience.
When Richard first spotted this 508 foot diameter potentially hazardous space rock it was 50 million miles from him traveling away from the Earth at 15 miles per second towards the orbit of Jupiter. After he reported his discovery observations to the Minor Planet Center it was observed by telescopes in Arizona, New Mexico, England, and Germany and was given the name 2016 XG1. For the 8 months after Richard discovered it this asteroid will continue to move away from the Sun till on July 11, 2017 it will be more than half way to the planet Jupiter. After that it will begin to pick up speed on it’s breath taking plunge towards the Sun. After crossing the orbits Venus and Mercury, on July 31, 2018 it will round the Sun at an amazing 46 miles per second. At 2016 XG1’s closest approach to our star it will be receiving nearly twice the amount of solar flux which heats the surface of the planet Mercury to 800F. 2016 XG1 must be made out of very durable rocky material since it has made this incredible voyage many times in the past. Fortunately it never comes closer than about 16 times the Moon’s distance from us. This is a very good thing since a stony asteroid like 2016 XG1 strikes our planet every 150,000 years or so and inflicts major damage over a hurricane sized foot print on the Earth’s surface.
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365 Days of Astronomy
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