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2015 TB145 – Big Rock Screams Past Earth Friday Night

I love a spectacle, or more precisely the high energy motion of a fast moving rock. Join me Friday night at TDS as we attempt to shoot asteroid TB145  as it screams past earth beginning at 10pm. The asteroid will appear just below the moon near Orion moving northeast. The asteroid will move 12 degrees in 6 hours passing under the moon brightening a full magnitude during its visible transit.

2015-TB145

Though it is being reported as a Halloween flyby, you won’t be able to see it Saturday night as it will fade to 17th magnitude and rate of motion will slow considerably compared to Friday night.

Just for giggles I ran this bad boy through a Asteroid Impact Calculator and obtained these amusing results that you may find interesting. I included the Ephmerides below for Friday/Saturday UTC.

Assuming a distance from Impact: 100.00 km ( = 62.10 miles )
Projectile diameter: 650.00 meters ( = 2130.00 feet )
Projectile Density: 3000 kg/m3
Impact Velocity: 35.00 km per second ( = 21.70 miles per second )
Impact Angle: 60 degrees
Target Density: 2500 kg/m3
Target Type: Sedimentary Rock

The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 5.5 x 105years

Atmospheric Entry:

The projectile begins to breakup at an altitude of 65600 meters = 215000 ft
The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 34.7 km/s = 21.5 miles/s
The impact energy is 2.60 x 1020 Joules = 6.20 x 104MegaTons.
The broken projectile fragments strike the ground in an ellipse of dimension 0.926 km by 0.802 km

Crater Dimensions:

Final Crater Diameter: 15.2 km ( = 9.45 miles )
Final Crater Depth: 672 meters ( = 2200 feet )

Thermal Radiation:

Time for maximum radiation: 368 milliseconds after impact
Visible fireball radius: 12 km ( = 7.43 miles )
The fireball appears 27.2 times larger than the sun
Thermal Exposure: 1.14 x 107 Joules/m2
Duration of Irradiation: 2.76 minutes

Effects of Thermal Radiation at 100km.

Clothing ignites
Much of the body suffers third degree burns
Newspaper ignites
Plywood flames
Deciduous trees ignite
Grass ignites
Seismic Effects at 100km distance:
The major seismic shaking will arrive approximately 20 seconds after impact.
Richter Scale Magnitude: 7.8

Mercalli Scale Intensity at a distance of 100 km: 

Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.

Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned.

Ejecta:

The ejecta will arrive approximately 2.4 minutes after the impact.
At your position there is a fine dusting of ejecta with occasional larger fragments
Average Ejecta Thickness: 13.4 cm ( = 5.28 inches )
Mean Fragment Diameter: 9.73 cm ( = 3.83 inches )

Air Blast:

The air blast will arrive approximately 5.05 minutes after impact.
Peak Overpressure: 98800 Pa = 0.988 bars = 14 psi
Max wind velocity: 171 m/s = 383 mph
Sound Intensity: 100 dB (May cause ear pain)

Damage Description:
Multistory wall-bearing buildings will collapse.
Wood frame buildings will almost completely collapse.
Glass windows will shatter.
Up to 90 percent of trees blown down; remainder stripped of branches and leaves.

Date             UT          R.A.           Decl.        Mag   Coord Motion     
                     h m s                                                     “/min    “/min  

2015 10 31 040000 04 54.57   +10 35.4  11.7  +44.26   +58.19

2015 10 31 050000 04 57.77   +11 38.0  11.6  +51.97   +67.28

2015 10 31 060000 05 01.54   +12 50.7  11.4  +61.55   +78.58

2015 10 31 070000 05 06.03   +14 16.1  11.3  +73.70   +92.81

2015 10 31 080000 05 11.45   +15 57.6  11.1  +89.52  +110.95

2015 10 31 090000 05 18.09   +17 59.8  10.9 +110.73  +134.36

2015 10 31 100000 05 26.40   +20 28.7  10.7 +140.21  +164.87

2015 10 31 110000 05 37.07   +23 32.7  10.6 +182.84  +204.79

2015 10 31 120000 05 51.26   +27 22.2  10.4 +247.40  +256.40

2015 10 31 130000 06 10.90   +32 09.5  10.2 +350.19  +319.86

2015 10 31 140000 06 39.46   +38 03.2  10.1 +521.73  +386.20

2015 10 31 150000 07 23.10   +44 51.6  10.1 +811.75  +419.80

2015 10 31 160000 08 30.97   +51 24.1  10.3+1240.33  +336.62

2015 10 31 170000 10 06.30   +55 00.0  10.7+1556.02   +68.29

2015 10 31 180000 11 45.91   +53 30.3  11.4+1346.68  -228.51

2015 10 31 190000 13 00.77   +48 23.9  12.2 +903.46  -353.92

2015 10 31 200000 13 49.21   +42 26.7  13.0 +575.57  -347.10

2015 10 31 210000 14 20.46   +37 03.8  13.8 +379.03  -295.92

2015 10 31 220000 14 41.50   +32 35.6  14.5 +262.01  -241.35

2015 10 31 230000 14 56.36   +28 58.2  15.1 +189.33  -195.19

2015 11 01 000000 15 07.30   +26 02.0  15.6 +141.94  -158.74

2015 11 01 010000 15 15.62   +23 38.0  16.1 +109.69  -130.51

2015 11 01 020000 15 22.14   +21 38.9  16.4  +86.95  -108.62

2015 11 01 030000 15 27.35   +19 59.2  16.8  +70.46   -91.52

2015 11 01 040000 15 31.62   +18 34.7  17.1  +58.22   -77.99

2015 11 01 050000 15 35.18   +17 22.3  17.3  +48.97   -67.16

2015 11 01 060000 15 38.20   +16 19.7  17.5  +41.89   -58.36

2015 11 01 070000 15 40.80   +15 25.0  17.8  +36.40   -51.14

2015 11 01 080000 15 43.08   +14 37.0  17.9  +32.09   -45.13

2015 11 01 090000 15 45.10   +13 54.4  18.1  +28.66   -40.08

2015 11 01 100000 15 46.92   +13 16.6  18.3  +25.90   -35.80

2015 11 01 110000 15 48.57   +12 42.7  18.4  +23.62   -32.13

2015 11 01 120000 15 50.08   +12 12.1  18.6  +21.71   -28.96

2015 11 01 130000 15 51.47   +11 44.6  18.7  +20.05   -26.22

2015 11 01 140000 15 52.75   +11 19.6  18.8  +18.58   -23.82

2015 11 01 150000 15 53.95   +10 56.9  18.9  +17.24   -21.71

2015 11 01 160000 15 55.05   +10 36.1  19.0  +15.98   -19.85

2015 11 01 170000 15 56.08   +10 17.1  19.1  +14.78   -18.22

2015 11 01 180000 15 57.03   +09 59.6  19.2  +13.63   -16.77

2015 11 01 190000 15 57.90   +09 43.5  19.3  +12.50   -15.48

2015 11 01 200000 15 58.69   +09 28.6  19.4  +11.42   -14.34