On the Hunt for rare rock after meteorite falls in December
University of Calgary geoscience professor asking for the public’s help.
A month after a spectacular fireball December 20, 2014, over the Rocky Mountains, University of Calgary researcher Alan Hildebrand is on a quest for rare meteorites.
In the early morning hours of December 20 a small piece of an asteroid entered Earth’s atmosphere high above Canal Flats, British Columbia, headed northeastwards towards Calgary, Alberta. Although western B.C. and eastern Alberta were overcast, the fireball was seen and imaged over the region between the clouds in both provinces. One spectacular still image was luckily taken by Brett Abernethy who was out with a friend imaging the night sky over Mt. Rundle near Banff when the fireball blazed an 80 km-long trail across the sky (See attached figure 1). Brett says, “We were looking north when everything lit up and we turned to see the fireball. It broke into at least three pieces and turned bright orange before fading away. After the initial shock I remembered that I was exposing a shot during the fireball and was overjoyed to discover that the shot was not overexposed.” Brett alerted the Calgary Herald to the event, who published his image which stimulated on-line discussion from other eyewitnesses.
Fireball over Mt Rundle near Banff
In his search for more information about the fireball Hildebrand contacted Rick Nowell at the College of the Rockies in Cranbrook, B.C., who recorded it with his Sandia all-sky video camera through patchy clouds, and was able to correctly mark the fireball’s start time to precisely 00:25:00. With this accurate time, another all-sky still image was obtained from the University of Calgary’s Rothney Astrophysical Observatory (RAO). With these additional images in hand, he and his team were able to triangulate its location in the sky.
“It was very interesting to see how precisely a fireball path could be located just from two pictures taken more than 100 km away. We probably know where it was, start to finish within 100 metres,” says Lincoln Hanton, a recent University of Calgary graduate working with Hildebrand. The video recorded in Cranbrook and the fireball’s trajectory also show that it was a relatively slow entry velocity which favours the fall of meteorites.
Hildebrand says the fireball shows extraordinary properties. “In the photo taken by Brett, the fireball becomes visible at approximately 100 km altitude, starts fragmenting at approximately 60 km, and has its last and biggest explosion at 43 km. Those altitudes are much higher than normal. That means the rock was likely a weak type of asteroid.”
Rare carbonaceous chondrite rock
Hildebrand says the apparent weakness displayed indicates that this rock was unusual, probably a carbonaceous chondrite, which is a specific type of stony meteorite that originates from the Outer Asteroid Belt. At that distance from the Sun water and carbon-bearing compounds condensed and mixed into asteroidal bodies. Carbonaceous chondrites represent only approximately three per cent of meteorites that fall on Earth.
“Eyewitness accounts indicate that meteorites fell after surviving the trip through the atmosphere; the estimated rock mass entering the atmosphere was about 100 kg, but the largest pieces on the ground are probably only 2 kg,” says Hildebrand. “The meteorites fell in a forested area of the upper White River valley. It’s a tough area to search.” (See Figure 2)
Satellite Map of Impact Area
Hildebrand says with the possibility of such a rare find his team will do some searching in the spring and encourage any others who can travel safely in this relatively remote area to search as well. How you can help
Hildebrand and his team are eager to talk with anyone who saw the fireball from Canal Flats, Fairmont Hot Springs, or Elkford, B.C. He encourages property owners in that region to check security camera systems for any shadows cast by the fireball. Anyone who had a wildlife camera in the region is also asked to check that date and time for moving shadows. Contact the University of Calgary at 403-220-8969 or via email at email@example.com.
Brett Abernethy 403-620-6929
Lincoln Hanton 403-220-8969
Alan Hildebrand 403-220-2291
Rick Nowell 250-489-2751 ext 3585
Figure 1: Brett Abernethy’s image of the Dec 20 fireball looking south over Mt. Rundle from near Johnson Lake. The fireball crossed the constellation of Orion and then began fragmenting where the trail brightens and broadens. Note the slight reddening at the fireball’s end as the surviving rock fragments slowed and cooled before falling to the ground. Image is a 40 second exposure taken with a Canon 5D Mark III with a wide angle Zeiss 21 mm lens which slightly compresses the vertical aspect of the image. (All rights reserved)
Figure 2: Satellite image of eastern British Columbia showing location of the fireball trajectory projected onto the ground and estimated meteorite fall area as a yellow ellipse. The end of the fireball was about 40 km east of Fairmont Hot Springs. An eyewitness in Canal Flats would have seen the fireball travel almost straight downwards in the sky. (Figure constructed on Google Earth base)
April 4 and the 22nd had some excellent Aurora Borealis, and Saturday the 22nd was also the Lyrid meteor shower. The skies were clear for a brief time, so I saw a few Lyrid meteors.
Jerry Mason’s photo above shows green auroral glow and blue streaks. Taken from College Way above Vernon at 10:30pm. I suspect the curved streak at right is a lens reflection from the streetlight at lower left.
Something new, have you heard about auroral proton arcs actually being a new high velocity 300km high, high temperature gas stream called “STEVE” acronym: Strong Thermal Emission Velocity Enhancement?
STEVE was assumed by aurora photographers to be a “proton arc”. (Protons can hit the upper atmospheric gases also and while the electrons they bump loose can cause a glowing light, it’s a broad, diffuse and dim glow unlike the structure of STEVE that is a narrow streamer with rotation and other motion.
Photo Credit: Karina & Amir, Vanexus Photography, Vancouver BC. Taken at Porteau Cove provincial Park in August 2016. “While it started as a thin white line, it transformed into vibrant greens and purples before fading away.”
Basics about STEVE, from NASA’s Aurorasaurus blog: source: http://blog.aurorasaurus.org/?p=449
1.STEVE appears ~10-20° (in latitude) closer to the equator (south in the Northern hemisphere) than where the normal green aurora is overhead. This means it could be overhead at latitudes similar to Calgary, Canada.
2.STEVE is a very narrow arc aligned East-West and extending for hundreds or thousands of miles.
3.STEVE emits light in mostly purplish colors. It is quite faint but is usually photographed with 5-10 second exposures.
4.Sometimes, it is accompanied by a rapidly evolving green short-lived picket fence structure.
5.STEVE can last 20 minutes or even longer.
6.STEVE appears to have a season. For instance, it has not been observed by citizen scientists from October 2016 to February 2017.
7.This phenomena has been reported from the UK, Canada, Alaska, northern US states, and even New Zealand.
“Ordinary auroras we see from the ground and space are caused by electrons precipitating down into the atmosphere,” Dennis Gallagher of the Nasa Marshall Space Flight Centre said last year. “Protons can cause auroras, too, but they are different. For one thing, proton auroras are brightest in the UV part of the spectrum, invisible to the human eye.”
There is some visible light from proton auroras, but these are broad and spread out, not tight and filamentary like the streaks seen in the photographs.
Eric Donovan, a professor of Physics and Astronomy from the University of Calgary:
With data gathered by Alberta’s network of aurora watchers, Eric Donovan found it coincided with a flyby from one of the three satellites from the European Space Agency’s Swarm magnetic field mission.
“As the satellite flew straight through Steve, data from the electric field instrument showed very clear changes. The temperature 300 km above Earth’s surface jumped by 3000°C and the data revealed a 25 km-wide ribbon of gas flowing westwards at about 6 km/s compared to a speed of about 10 m/s either side of the ribbon,” explained U of C astronomer Eric Donovan in an ESA blog post.
“It turns out that STEVE is actually remarkably common, but we hadn’t noticed it before. It’s thanks to ground-based observations, satellites, today’s explosion of access to data and an army of citizen scientists joining forces to document it.
“Swarm allows us to measure it and I’m sure will continue to help resolve some unanswered questions.”
Roger Haagmans, Swarm’s mission scientist added that there is still a lot we need to learn about Steve. For example, it is not created by the interaction of solar particles with the Earth’s magnetic field, meaning it is not classified as an Aurora and requires further investigation.
So, instead of an aurora caused by solar particles slamming into air molecules, this turned out to be a super-heated ribbon of gases, where the air molecules were emitting light simply due to the heat, like the filament of an incandescent light bulb.
According to NASA’s Aurorasaurus blog, there were more than 50 observed sightings of Steve (which has since been hammered into the acronym Strong Thermal Emission Velocity Enhancement) last year and they’re hoping to gather more data in 2017.
This is the College All-sky meteor cam showing the eleven brightest Dec 15 meteors stacked on one frame, from 7pm until 2am when it clouded over. North at top of photo and East to the left. Two bright fireballs on the horizon! That trail of dots there is Jupiter rising. Some clumps of dots are just aircraft strobes.
And here’s the 11 meteor stack for Dec 14 from 9pm until 1:15am, when it clouded over. About the same each evening.
And just for fun, here’s all the photos stacked from the camera watching Ursa Minor over a 43 minute period, taken with 30 second exposures, 28mm f/2.5 lens, 1000 ISO.
Geminids from Invermere
This photo was taken facing South, showing Orion before the Moon rose, from Invermere by Robert Ede. He says: I saw some beauties. A few with smoke trails.
(Email from Cattle Point Dark Sky Urban Star Park volunteer William Smith)
Dear Gerhard Drolshagen : On the Orbit of WT1190F (aka Snoopy)
Does object get captured weeks before and go into earth’s orbit, slowly losing speed and descending? OR does it come shooting directly into the earth’s atmosphere – almost perpendicular to a tangent ie pointing at the earth’s centre? This is important because if it orbits the earth one or two times as it slows down, then we might see it in the dark of the late evening where we are on West Coast of North America..
If you look at the ISS paths then focus in on the one which crosses southern India, this might indicate that SNOOPY (coming also NW-> SE) would pass over Panana, Bahamas, Northern Spain , Mediterranean and then IRAN . No luck for west coast of USA/Canada where I am.
Gerhard Drolshagen forwarded your message to me. Here is some of the info we have on WT1190F.
The object has been in Earth’s orbit at least since 2009. It has been moving in an elongated orbit with apogee at about twice the distance of the Moon, and perigee getting closer and closer to the Earth, until the upcoming re-entry. Since 2009, it has completed dozens of orbits around the Earth, and each orbit is about a month long.
The impact trajectory is not very vertical, but still much steeper than the typical re-entry of a low-orbiting satellite. It will come in with an angle of about 20° from the horizontal (=70° from vertical).
Given the fact that the orbit is so long, the geometry is totally different from a pass of the ISS. The latter orbits the Earth in about 90 minutes, while WT1190F takes weeks. So the current pass is actually the last part of the last orbit for this object.
Anyway, from a geometry point of view, it will definitely be observable from north America in the morning hours of November 12. However, it will be very faint, magnitude 19 or so, invisible by eye even with a large telescope. A CCD camera and at least a moderate-size telescope will be needed to get an image of it at that time.
Even for Europe and Northern Africa, which are the countries best-placed to observe it just hours before impact, it will only reach magnitude 15 or so, too faint for anything but images with a good telescope.
If you want to get an ephemeris for a specific site, I suggest you use this page from the Minor Planet Center: http://www.minorplanetcenter.net/iau/artsats/artsats.html. Just select WT1190F, enter the required information, and you will get your specific ephemeris based on the latest data.
Let us know if you need any additional info, and thanks for contacting us.
For the past few weeks you may have noticed meteors shooting across the sky. There is the Geminid meteor shower and three other smaller meteor showers in progress. Although with the bright moon, the dimmer meteors aren’t as easily seen.
The Geminids started Dec 4 and end Dec 17. On Sat Dec 14, at their peak they can give 120 meteors per hour. Fairly slow for meteors, they are travelling at a speed of 35 km/s. (That’s still pretty fast. For comparison, the International space station orbits at 8km/s, and goes around the Earth in 90 minutes.)
There are three smaller showers in progress: The sigma-Hydrids from Dec 03-Dec 15, peaked on Thurs Dec 12 with 3 meteors/hour, at speeds of 58km/s. The Comae Berenicids from Dec 12-Jan 23 peaked on Monday Dec 16 with 3 meteors/hour, at speeds of 65km/s And the December Leo Minorids from Dec 05-Feb 04 peak on Thurs Dec 19 with 5 meteors/hour at 64km/s
Don’t forget Comet Lovejoy in the early morning around 7am, before sunrise, a small fuzzy blob visible between Hercules and Corona Borealis above the eastern horizon. The bright moon drowns it out currently, so you’ll need binoculars or a telescope to see it and its slight tail.
2015-11-13 : 10:21 PST. Splashdown was last night at 22:19 PST in SRI LANKA off coast of Matara. Was late evening on USA Westcoast Thursday. Please enjoy my Blog. This is a conversation between young post-grad scientist Subath Amaradasa of the “Near Earth Objects” Team at the University of Ruhuna, who is on ground with French scientists from European Space Agency and William Smith who is the Hoyle-Shield coordinator at Cattle Point DARK SKY Urban Star Park, Victoria, Canada.
PS There will be a post script to the Snoopy event. Snoopy is almost certainly the Apollo 10 lunar lander – aka Snoopy. Its orbit which reaches way past the moon, makes this almost certain. No wonder it burned out. Very high speed entering the upper atmosphere. Ten times the speed of the fastest bullet on earth. Being small and with no shielding, no wonder it quickly burned out. Thanks to Rick Nowell for inspiring Subath Amaradasa and his “Near Earth Object” team at the University of Ruhuna in Matara, Sri Lanka.