Posted on 09/06/2010 4:49:27 PM PDT by TaraP
Within the space of less than an hour on September 5, the Mount Lemmon Survey discovered two objects which will both pass by the Earth on September 8 at a distance closer than the Moon! This unprecedented coincidence provides an exciting observing challenge for amateurs although those observing from the UK will not have the best views.
The intrinsically smaller object, 2010 RF12, will be the more favourable observing target in that it passes closest at about 0.21 lunar-distance, i.e. about 80,000 km.
Tonight from the UK (Sep 6/7) this object will be 17th magnitude but by tomorrow (Sep 7/8) it will be brightening rapidly from 16th to 15th magnitude and be accelerating from an apparent speed of about 30 "/min to 50 "/min.
It passes closest around 2100 UT on the 8th but by then it will be difficult from any location on the Earth.
The larger object, 2010 RX30, only approaches to within about 0.66 lunar-distances of the Earth but will be more favourably placed for UK observers and should be able to be followed to within about 6 hours of closest approach which takes place around 1000 UT on the 8th. It will be visible all night on Sep 7/8 being 16th magnitude at first but then brightening to 15th mag.
The problem however is its apparent speed in that it will be racing across the sky at between 2-5 ARCSEC/SEC.
Observers with access to telescopes located in other parts of the world especially in the southern hemisphere could witness 2010 RF12 reach 13th magnitude around 1600-1700 UT on the 8th.
As seen visually in a large telescope (30-cm aperture or more), its motion across the sky would be very apparent in real time.
Uh, the sky is falling?
Too cool indeed. I will have to go to my friends home that has a telescope.
2010 RF12
Earth Impact Risk Summary
Torino Scale (maximum) 0
Palermo Scale (maximum) -5.16
Palermo Scale (cumulative) -5.11
Impact Probability (cumulative) 6.4e-04
Number of Potential Impacts 30
Vimpact 12.26 km/s
Vinfinity 5.10 km/s
H 28.1
Diameter 0.008 km
Mass 7.2e+05 kg
Energy 1.3e-02 MT
all above are mean values
weighted by impact probability
http://neo.jpl.nasa.gov/risk/2010rf12.html
Nothing they can’t shrink with giant tube of Preparation A.
Al Gore denies that asteroids have an impact on earth’s weather.
“Bush’s Fault!”
Still, .21 lunar distances at that speed is troubling.
You bet your asteroids it’s Bush’s Fault!
“Tonight from the UK (Sep 6/7) this object will be 17th magnitude but by tomorrow (Sep 7/8) it will be brightening rapidly from 16th to 15th magnitude and be accelerating from an apparent speed of about 30 “/min to 50 “/min. “
You might have an easier time seeing Pluto with a 3-inch refractor in Times Square!
unless I missed it they left out a very key piece of information - how large are these and what would have happened if they had made a direct hit on Earth?>
That’ll show those Mayans!
These are 10m and 15m wide asteroids. The one that left the crater in Arizona is 1184m wide. Not totally uncommon for one of these to hit the atmosphere.
On the day 8 September 2 asteroids, rare event, will pass between the Earth and the Moon.
The first (2010 RX30) will pass at 0.0017 A.U.; it has a diameter of 15 meters.
The second (2010 RF12) will pass at only 0.0005 A.U., but with a smaller diameter, 10m.
They follow ephemerides and and orbital elements
2010 RX30 Earth MOID = 0.0011 AU
Epoch 2010 July 23.0 TT = JDT 2455400.5 MPC
M 190.93133 (2000.0) P Q
n 1.32341303 Peri. 321.19520 -0.61041381 -0.79186476
a 0.8216227 Node 166.39094 +0.74498508 -0.58192799
e 0.3960140 Incl. 4.52882 +0.26905802 -0.18522962
P 0.74 H 27.1 G 0.15 U 7
Date TT R. A. (2000) Decl. Delta r Elong. Phase V
2010 09 07.0 23 59.46 +22 25.9 0.00822 1.015 148.0 31.7 18.1
2010 09 07.1 23 56.02 +22 47.3 0.00767 1.014 148.1 31.6 17.9
2010 09 07.2 23 52.02 +23 11.8 0.00711 1.014 148.2 31.6 17.7
2010 09 07.3 23 47.32 +23 39.8 0.00656 1.013 148.3 31.5 17.6
2010 09 07.4 23 41.70 +24 12.4 0.00601 1.013 148.3 31.6 17.4
2010 09 07.5 23 34.89 +24 50.4 0.00546 1.012 148.2 31.7 17.2
2010 09 07.6 23 26.48 +25 35.2 0.00492 1.012 147.9 31.9 16.9
2010 09 07.7 23 15.85 +26 28.5 0.00438 1.011 147.4 32.4 16.7
2010 09 07.8 23 02.09 +27 31.9 0.00386 1.011 146.5 33.4 16.5
2010 09 07.9 22 43.70 +28 47.0 0.00335 1.010 144.9 34.9 16.2
2010 09 08.0 22 18.28 +30 12.9 0.00287 1.010 142.2 37.7 15.9
2010 09 08.1 21 42.01 +31 40.3 0.00242 1.009 137.5 42.4 15.7
2010 09 08.2 20 49.53 +32 36.0 0.00204 1.009 129.8 50.1 15.5
2010 09 08.3 19 37.11 +31 37.7 0.00177 1.008 117.8 62.2 15.6
2010 09 08.4 18 12.06 +27 03.5 0.00166 1.008 101.8 78.1 15.9
2010 09 08.5 16 54.08 +19 26.0 0.00174 1.007 85.1 94.8 16.7
2010 09 08.6 15 55.42 +11 38.7 0.00199 1.007 71.3 108.6 17.7
2010 09 08.7 15 14.60 +05 27.2 0.00235 1.006 61.4 118.5 18.7
2010 09 08.8 14 46.18 +00 56.5 0.00279 1.006 54.6 125.2 19.6
2010 09 08.9 14 25.82 -02 18.8 0.00326 1.005 49.9 129.9 20.4
2010 09 09.0 14 10.72 -04 42.5 0.00377 1.005 46.6 133.3 21.0
Time to go to the store, again?
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