On 6/2/2018 1:27 PM, Bill Gray pluto@... [mpml] wrote:> Hi Alan,> I've just updated the impact plot to show UT times of impact :> This also reflects some new info on the astrometric uncertainties.> It assumes sigmas of 0.7 arcsec for the first four discovery observations> (which didn't track the object's motion). The next four observations> from (I52) _did_ track the object and have 0.3" assumed uncertainty;> the last four, from (G96) but tracking the motion, are at 0.5". And> a half-second timing error is assumed for all of them.> Following is the astrometry with COM keywords used to specify the> uncertainties. Use these in Find_Orb, on-line or in the Windows or> Linux flavors, and it'll "see" the COM sigma lines and set uncertainties> accordingly.> The revised sigmas expand the impact area a good bit. Impacts as far> west as Madagascar or as far east as over the International Date Line are> now entirely possible. Or even just flat-out missing us; I'm now getting> an 85% impact probability. (And Scout is still getting only a 30%> probability... I still suspect that means we have somewhat different> assumptions. Maybe in our over-observing parameters?)> If it hit at about 15:00, it would have been in New Guinea and at> H=31.7. If it hit off Madagascar at about 16:30, we'd be looking at> an H=30.7 object.> -- Bill> COD G96> COM Posn sigma 0.7> COM Time sigma 0.5> ZLAF9B2 C2018 06 02.34330 16 11 10.34 -11 19 34.7 G96> ZLAF9B2 C2018 06 02.34851 16 10 59.30 -11 20 21.6 18.2 G G96> ZLAF9B2 C2018 06 02.35373 16 10 48.15 -11 21 08.9 18.3 G G96> ZLAF9B2 C2018 06 02.35895 16 10 36.57 -11 21 57.6 18.0 G G96> COD I52> COM Posn sigma 0.3> COM Time sigma 0.5> ZLAF9B2 C2018 06 02.39785 16 09 02.60 -11 28 26.0 17.5 GUNEOCPI52> ZLAF9B2 C2018 06 02.39804 16 09 02.13 -11 28 28.1 17.2 GUNEOCPI52> ZLAF9B2 C2018 06 02.39822 16 09 01.62 -11 28 30.1 17.5 GUNEOCPI52> ZLAF9B2 C2018 06 02.39840 16 09 01.15 -11 28 31.8 17.7 GUNEOCPI52> COD G96> COM Posn sigma 0.5> COM Time sigma 0.5> ZLAF9B2 C2018 06 02.40223 16 08 51.04 -11 29 13.6 17.7 GUNEOCPG96> ZLAF9B2 C2018 06 02.40233 16 08 50.78 -11 29 15.1 17.9 GUNEOCPG96> ZLAF9B2 C2018 06 02.40242 16 08 50.58 -11 29 16.1 17.8 GUNEOCPG96> ZLAF9B2 C2018 06 02.40251 16 08 50.28 -11 29 16.8 17.8 GUNEOCPG96> On 2018-06-02 13:05, AlanCahill neoprog@... [mpml] wrote:> > Any idea of dates and timing for close approach?> > Cheers> >> > Alan> > Abbeydale Observatory (J94)> >> > http://mountabbeydale.com/index.htm > >> > Sent from Mail for Windows 10> >> > From: Bill Gray pluto@... [mpml]> > Sent: 02 June 2018 16:46> > To: Peter Birtwhistle; neo_followup@yahoogroups.com ; MPML> > Subject: Re: {MPML} Re: [neo_followup] Further on ZLAF9B2> >> >> > Hi Peter,> >> > It's tricky, but possible, to get non-impacting solutions.> > I'm not quite ready to say it's an impactor, and it now seems> > unlikely we'll see follow-up data (except in the form of infrasound> > or satellite detections or somebody saying, "Wow, that was a big> > fireball!")> >> > JPL's Scout system has caught the new data and produced an update,> > with a 30% chance of impact :> >> > https://cneos.jpl.nasa.gov/scout/#/object/ZLAF9B2 > >> > I'm getting a near-certain impact, either a few minutes ago> > (toward the east end of the plot) or in a couple of hours (west end> > of the plot) :> >> > https://projectpluto.com/temp/z.png > >> > Still looking into the cause of the difference, but it'll probably> > come down to differences in uncertainties assumed in the data. (Insert> > here my usual rant about the desirability of astrometric uncertainties> > so that the Scout folks and I don't have to make guesses about how> > good the data are.)> >> > -- Bill> >> > On 2018-06-02 10:26, Peter Birtwhistle peter@... [mpml] wrote:> >> Hi Bill,> >>> >> What would you give for the chance of this one surviving perigee? All of> >> the solutions I get with the revised astrometry look like it won't, but> >> you're *much* better at this stuff than I am!> >>> >> Peter> >> J95> >>> >> On 02/06/2018 13:30, Bill Gray pluto@... [neo_followup] wrote:> >>>> >>> Hello all,> >>>> >>> Alex Gibbs at CSS has re-measured the first few discovery images and> >>> was able to get a position from a previously unmeasured image. So this> >>> replaces the first three positions and adds a fourth. It causes enough> >>> of a change in the situation that I'd recommend using the following for> >>> your ephems. Cut and paste into> >>>> >>> https://www.projectpluto.com/fo.htm > >>>> >>> and do the usual setting of your observatory code, time span, etc.,> >>> and you'll get ephems. That ought to cover us, at least until NEOCP> >>> updates. (At which point, I don't know if NEOCP will include geocentric> >>> perturbations, so I'd still recommend checking with this astrometry and> >>> Find_Orb.)> >>>> >>> For some reason, the on-line Find_Orb isn't providing uncertainties.> >>> But they're already almost two degrees; if it wasn't such a bright object,> >>> we'd be in serious trouble. Still a long shot on such short notice...> >>>> >>> -- Bill> >>>> >>> ZLAF9B2 C2018 06 02.34330 16 11 10.34 -11 19 34.7 G96> >>> ZLAF9B2 C2018 06 02.34851 16 10 59.30 -11 20 21.6 18.2 G G96> >>> ZLAF9B2 C2018 06 02.35373 16 10 48.15 -11 21 08.9 18.3 G G96> >>> ZLAF9B2 C2018 06 02.35895 16 10 36.57 -11 21 57.6 18.0 G G96> >>> ZLAF9B2 C2018 06 02.39785 16 09 02.60 -11 28 26.0 17.5 GUNEOCPI52> >>> ZLAF9B2 C2018 06 02.39804 16 09 02.13 -11 28 28.1 17.2 GUNEOCPI52> >>> ZLAF9B2 C2018 06 02.39822 16 09 01.62 -11 28 30.1 17.5 GUNEOCPI52> >>> ZLAF9B2 C2018 06 02.39840 16 09 01.15 -11 28 31.8 17.7 GUNEOCPI52> >>> ZLAF9B2 C2018 06 02.40223 16 08 51.04 -11 29 13.6 17.7 GUNEOCPG96> >>> ZLAF9B2 C2018 06 02.40233 16 08 50.78 -11 29 15.1 17.9 GUNEOCPG96> >>> ZLAF9B2 C2018 06 02.40242 16 08 50.58 -11 29 16.1 17.8 GUNEOCPG96> >>> ZLAF9B2 C2018 06 02.40251 16 08 50.28 -11 29 16.8 17.8 GUNEOCPG96> >>>> >>>> >>> >>> >>> >> ------------------------------------> >> Posted by: Peter Birtwhistle < peter@... > >> ------------------------------------> >>> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~> >>> >> Posts to this list or information found within may be freely used, with the> stipulation that MPML and the originating author are cited as the source of the> information.> >> ------------------------------------> >>> >> Yahoo Groups Links> >>> >>> >>> >> >> >> >> > [Non-text portions of this message have been removed]> >> >> >> > ------------------------------------> > Posted by: AlanCahill < neoprog@... > > ------------------------------------> >> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~> >> > Posts to this list or information found within may be freely used, with the> stipulation that MPML and the originating author are cited as the source of the> information.> > ------------------------------------> >> > Yahoo Groups Links> >> >> ></s>A local farmer near Ottosdal in North West has shared CCTV footage of what appears to be a meteorite hitting the earth at 18:49 Saturday night.





According to a member of a neighbourhood watch, who shared the video with OFM News on social media, they were doing night patrol in the area of Hartbeesfontein when they received reports from Klerksdorp, approximately 30 kilometres away. People reportedly saw ‘a light’ falling from the sky and initially thought it was an aeroplane.

He told OFM News that everyone came together and started searching, but shortly thereafter received the CCTV footage from Barend Swanepoel and Wikus van Zyl from a farm near Bospoort and Gardau, an area not too far from Klerksdorp. On the video it appears to be more like a meteor that has fallen.

What could have possibly been the same meteor was lighting up the sky in China earlier Saturday evening.

According to Itv News, witnesses were stunned by a dazzling light which quickly took the form of a “flaming ball” over Yunnan Province. The Yunnan Observatory of the Chinese Academy of Sciences said it was a meteor.

Social media has also made mention of a meteorite that was discovered and given the temporary label – ZLAF9B2 – which reportedly slammed into the atmosphere over Botswana.

According to a physicist and Very-long-baseline Interferometry (VLBI) radio astronomer, Marshall Eubanks, this is a rare case of discovery before impact.

OFM News last night tracked the path of meteorite ZLAF9B2, with a projected diameter of between 0.5m and 3,5m, as plotted by Bill Grey on Twitter.

It looks like ZLAF9B2 hit the atmosphere over Botswana. There are reports of a vapor trail seen there. Plot is from Bill Grey https://t.co/ylIPUgKPhY pic.twitter.com/pqxf1oACBi

— Asteroid Initiatives (@AsteroidEnergy) June 3, 2018">

It looks like ZLAF9B2 hit the atmosphere over Botswana. There are reports of a vapor trail seen there. Plot is from Bill Grey https://t.co/ylIPUgKPhY pic.twitter.com/pqxf1oACBi — Asteroid Initiatives (@AsteroidEnergy) June 3, 2018

This a developing story.

It seems now that the asteroid *did* hit the atmosphere and exploded: the very bright fireball repored over Botswana in https://t.co/EhmmN0JxoX fits the asteroid's trajectory perfectly in space and time as https://t.co/KRS0iDRd0L (View / Expand Messages / scroll down) explains.

— Daniel Fischer (@cosmos4u) June 2, 2018">

It seems now that the asteroid *did* hit the atmosphere and exploded: the very bright fireball repored over Botswana in https://t.co/EhmmN0JxoX fits the asteroid's trajectory perfectly in space and time as https://t.co/KRS0iDRd0L (View / Expand Messages / scroll down) explains. — Daniel Fischer (@cosmos4u) June 2, 2018









CCTV FOOTAGE: Barend Swanepoel and Wikus van Zyl

OFM News</s></s>A small asteroid discovered Saturday morning, determined to head for Earth, impacted the planet's atmosphere just a few hours later, according to NASA.

The cosmic boulder, named asteroid 2018 LA (and previously listed as ZLAF9B2), was estimated to be only about 6 feet (2 meters) across. It was first spotted by the Catalina Sky Survey in Arizona.

"The discovery of asteroid 2018 LA is only the third time that an asteroid has been discovered to be on an impact trajectory," said Paul Chodas, manager of NASA's Center for Near-Earth Object Studies (CNEOS), in a statement. "It is also only the second time that the impact location was predicted well ahead of the event itself."

All three asteroids burned up in the atmosphere and caused no reported damage.

NEO watchers calculated that asteroid 2018 LA would enter the atmosphere somewhere over a corridor extending from Africa across the Indian Ocean to Papua New Guinea.

The final moments of the asteroid's existence appear to have been caught Saturday evening from a webcam in South Africa in the below clip. Although it looks like the fireball impacts the ground, it is really just disappearing over the horizon. NASA says it disintegrated several miles over the surface as it lit up the sky.

"This was a much smaller object than we are tasked to detect and warn about," said Lindley Johnson, planetary defense officer at NASA Headquarters. "However, this real-world event allows us to exercise our capabilities and gives some confidence our impact prediction models are adequate to respond to the potential impact of a larger object."

One such larger object was the asteroid that went completely undetected until it collided with the atmosphere over Russia in 2013, creating a shock wave that blew out thousands of windows in the town of Chelyabinsk, causing a number of minor injuries.

How much it's worth freaking out over these undetected or late-detected asteroids is up for debate. The smallest asteroids like 2018 LA are the hardest to spot, but also the least likely to do any damage. That said, it can never hurt to have more telescopes and eyes pointed at the sky looking for the next space rock aiming to knock on our door ... or break it down.

Solving for XX: The tech industry seeks to overcome outdated ideas about "women in tech."</s>A small asteroid discovered on Saturday morning, June 2, 2018, surprised astronomers when its trajectory suggested it would pass very, very close to Earth just hours after being detected. The object has been given the temporary designation of ZLAF9B2. There are reports of sightings of a bright meteor, as well as a video that may be related to the event, from Barend Swanepoel in South Africa. He reports the video as being:

Another witness in South Africa described the meteor as very bright, and showing a yellow color.

This space rock had an estimated size of only 10-16 feet (3 to 5 meters) in diameter. If it struck (and sometimes they do, and meteorite pieces are found), it was too small to cause serious damages. In contrast, the impressive meteor seen over Chelyabinsk, Russia, in February, 2013 was an estimated 60 feet wide (20 meters). It broke windows in six Russian cities and caused more than 1,500 people to seek medical attention, mostly due to injuries from flying glass. The June 2 asteroid wasn’t big enough to do anything like that, but it was big enough to produce a spectacular, very bright meteor.

Help EarthSky keep going! Please donate what you can to our annual crowd-funding campaign.

The 60-inch (1.5-meter) telescope at Mt. Lemmon, which is part of the Catalina Sky Survey in Arizona, was the first to detect asteroid ZLAF9B2 on Saturday morning, according to clocks in North America. Alex Gibbs – principal engineer at the Catalina Sky Survey – posted these images of the object on his Facebook page:

According to NASA/JPL’s Center for Near Earth Object Studies (CNEOS), asteroid ZLAF9B2 approached Earth at 27,738 miles per hour (44,640 km per hour).

Models began suggesting that – in case of impact – the asteroid would enter Earth’s atmosphere somewhere between Indonesia, the Indian Ocean, or South Africa.

The reported observation of the color yellow in the sighted meteor is of interest because colors in a meteor provide a hint of its composition. Yellow suggest the rock contains sodium, as was also in the 2013 Chelyabinsk meteor.

Small asteroids are difficult to detect. Some space rocks might be dark, and may only reflect a small amount of sunlight as they may already be somewhat close to our planet.

However, as bigger asteroids reflect more light, they are usually detected weeks or months before closest approach.

Confirmation of the event is continuing to trickle in:</s>A small asteroid — which had just been discovered earlier in the day — disintegrated over Africa on Saturday, NASA said.

The tiny space rock, roughly six feet long, entered Earth’s atmosphere at the high speed of 38,000 mph and broke apart several miles above the surface, creating a bright fireball that lit up the evening sky, the agency said.

The event was witnessed by a number of observers and was caught on webcam video.

The object surprised astronomers shortly after its discovery, when its trajectory suggested it would pass very, very close to Earth just hours later, according to EarthSky.org.

When it was spotted, astronomers realized there was a possibility of an Earth impact. However, the asteroid was determined to be very small and therefore harmless.

“This was a much smaller object than we are tasked to detect and warn about,” said Lindley Johnson, Planetary Defense Officer at NASA Headquarters. “However, this real-world event allows us to exercise our capabilities and gives some confidence our impact prediction models are adequate to respond to the potential impact of a larger object.”

The object was first given the temporary designation of ZLAF9B2, but has now been renamed as asteroid 2018 LA by the International Astronomical Union.

It was much smaller than the meteor that exploded over Chelyabinsk, Russia, in February 2013, which was an estimated 60 feet wide. That meteor broke windows in six Russian cities and caused more than 1,500 people to seek medical attention, mostly due to injuries from flying glass, EarthSky said.

These are the discovery observations of asteroid 2018 LA from the Catalina Sky Survey, taken June 2, 2018. About eight hours after these images were taken, the asteroid entered Earth's atmosphereand disintegrated in the upper atmosphere near Botswana, Africa.
A 2–5-metre (6 ft 7 in–16 ft 5 in) wide asteroid named 2018 LA was estimated (before impact) to have an 82% chance of having impacted Earth today, with several corroborating reports from Botswana. An OFM media report from near Klerksdorp, North West province, South Africa, describes "'a light' falling from the sky" at 18:49 (UTC+02:00) Saturday night.