Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: Eps.289 & 290 : Strange Comet & Screaming Aten
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s 2 topics:
- C2016 Q4 Kowalski has an orbit similar to 2060 Chiron, which has rings. 10199 Chariklo has rings as well. Kowalski has both comet-like and asteroid-like aspects.
- 2016 RT, discovered by our podcaster, Dr. Grower, is a fast-moving Aten asteroid. These asteroids spend most of their time inside Earth’s orbit but many cross our orbit and are potentially hazardous objects.
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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:
289-Strange Comet
C/2016 Q4 (Kowalski) is my Catalina Sky Survey teammate Richard Kowalski’s 14th comet discovery. It orbits the Sun once every 68 years on a cold path between Saturn and Neptune.
Kowalski’s new comet has an orbit and likely other characteristics similar to the minor planet/comet Chiron. At perhaps 150 miles in diameter Chiron is a strange object. It is the 6th object in the solar system which has rings. Besides the gas giants Jupiter, Saturn, Uranus, and Neptune only the remote asteroid Chariklo and Chiron have rings. When it was first discovered in 1977 Chiron was classified as a minor planet. In 1988 Astronomers were surprised to observe Chiron brightening by more than 75% since asteroids don’t usually behave like this. A year later Chiron was observed to have a gas cloud or coma surrounding it. The surprises continued when Chiron’s ring system was discovered in 1993. When it’s ring system is face on it reflects more light than when they are edge on which accounts for Chiron’s brightness variations.
As a Chiron type object Kowalski’s discovery has the characteristics of both an asteroid and a comet. We don’t know if it has rings or moons.
As asteroid hunters, every night, we are treated to a tour of the Universe as we view the images of millions of stars and other objects in search of Earth approaching asteroids. What will we come up with next?
290-Screaming Aten
I knew from the short regularly space streaks on the four images I had just obtained with the Catalina Sky Survey’s 60 inch on Mount Lemmon, Arizona, I was looking at the path of an Earth approaching object. Closer scrutiny revealed this previously unknown object to be traveling across the sky at an amazing rate of 17 full moon diameters per day. For the next 38 hours this space rock was observed by telescopes in Arizona, Czech Republic, Hungary, Italy, and Illinois. However, it wasn’t until my Catalina Sky Survey teammate Rose Matheny tracked it two nights later that the Minor Planet Center was able to give it the name 2016 RT and calculate it’s orbit around the Sun.
Then the puzzlement began.
The NASA/JPL Near Earth Object website classified 2016 RT as an Aten. An Aten Earth approaching asteroid is one that spends most of its time inside the Earth’s orbit. Usually, when an Aten passes us or we pass it the situation is like one vehicle passing the other when both are going the same direction on a freeway. This configuration makes for a slow relative speed between a typical Aten and the Earth. Turns out, 2016 RT is an unusual Aten in that its orbit is inclined 38 degrees to the path of the Earth around the Sun. It’s high relative speed is caused by the fact that our paths intersect at a large angle making it similar to two vehicles coming together on intersecting highways.
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365 Days of Astronomy
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