Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: Eps.463 & 464: Exiled Asteroid & Big Attira
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s 2 topics:
- Astronomers used the Very Large Telescope in Chile to study the 117 mile diameter asteroid 2004 EW95 which orbits in the Kupier Belt.
- Richard Kowalski spotted 2018 JB3, a rare Atira type Earth approaching asteroid whose orbit lies completely inside that of the Earth.
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:
463-Exiled Asteroid
According to a paper published in the Journal Nature, eons ago the giant planet Jupiter formed about three and a half times as far from the Sun as our Earth is today. In what lead author Dr. Kevin Walsh of the Southwest Research Institute in Boulder, Colorado calls the “Grand Tack” gas surrounding our young Sun caused Jupiter to spiral inward to bring it near to the present position that Mars occupies today. From there, in a sailing ship like tack maneuver, under the influence of Saturn’s gravitational pull, Jupiter sailed away from the Sun to eventually land where it is today 5.5 times our distance from the Sun. During that process enough material was left in Jupiter’s wake to form Venus, Earth, Mars, and the asteroid belt as we know them today. In addition bit’s and pieces were flung out into the Kuiper Belt some 30 to 50 times further from the Sun then we are. Recently astronomers used the European Southern Observatories Very Large Telescope in Chile to measure the pattern of colors reflected and thus the chemical composition of the 117 mile diameter asteroid 2004 EW95 which orbits the Sun on a path in the Kupier Belt out past the planet Uranus. Their data show that 2004 EW95’s carbonaceous composition indicates that it was formed in the inner solar system and was likely exiled to it’s lonely position at the outer limits of the solar system during Jupiter’s rampaging tack maneuver long ago.
464-Big Attira
Using our Schmidt telescope on Mt. Bigelow, Arizona, my Catalina Sky Survey teammate Richard Kowalski was searching for Earth approaching objects, as close to the rising Sun as possible, when he discovered an unusual object streaking through the constellation of Andromeda. Additional observations by telescopes in California, Germany, Japan, and the Canary Islands allowed scientists at the Minor Planet Center to determine that what Richard spotted is a rare Atira type Earth approaching asteroid whose orbit lies completely inside that of the Earth. They also estimated it’s size to be 3,500 feet in diameter and gave it the name 2018 JB3. From the Earth and it’s orbital positions, an Atira asteroid like 2018 JB3 appears to humans only as a thin crescent and never shows it’s entire full moon face to us. This geometry makes an Atria particularly dangerous since it is always close to the Sun in our sky and it is dim for it’s size to boot. Since the impact of a 1 kilometer diameter asteroid like 2018 JB3 could cause global climate change it is fortunate that 2018 JB3’s present orbit never brings it closer than about 53 times the Moon’s distance from us, however, Richard’s discovery of it reminds asteroid hunters to continue to search near the Sun so that a large dangerous object does not sneak up undetected on the residents of planet Earth.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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