From: TerryMosel
aol.com
Date: Thu, 18 Mar 2004 14:58:09 EST
Subject: Closest Asteroid flyby!
Hi all,
CLOSEST FLYBY EVER!
Less than 5 hours from the time this message is being issued, a tiny, newly
discovered asteroid will make the closest flyby past Earth that has ever been
predicted by astronomers.
The object, dubbed 2004 FH, (also known as NEO. 2003 FH )
is probably only about 20 meters in diameter (the size of a big house). An
electronic circular issued late on March 17th by the Minor Planet Center (MPC)
in Cambridge, Massachusetts, indicates that it will definitely NOT hit the
Earth. [If it did, the impact energy would be around 20 Megatons, or over 1,000
times that of the Hiroshima bomb. TM] It will pass about 49,000 kilometers
(30,500 miles) from Earth's center,
which is one-eighth the distance of the Moon. [That's only 26,500 miles from
the Earth's surface. TM]
This object was discovered on March 16th by astronomers of MIT's Lincoln
Near-Earth Asteroid Research (LINEAR) survey in Socorro, New Mexico. Further
observations made on the 17th at Klet Observatory (Czech Republic),
Starkenburg Observatory (Germany), and Modra Observatory (Slovenia) helped
the MPC compute its exact trajectory.
The flyby scenario for 2004 FH goes like this:
* At 18 hours Universal Time on March 18th, the asteroid will be 12th
magnitude as it glides just south of the star Spica in Virgo, heading west
* By 22 hours UT on the 18th, it will have brightened to 10th magnitude when
it passes closest to Earth in the constellation Antlia.
* At 0 hours UT on March 19th -- which is around the time darkness falls on
the East Coast of North America on Thursday, March 18th -- it will have
faded
back to 12th magnitude as it shoots by Sirius near the open star cluster
Messier 41. By then it will be receding from Earth and heading back into
space.
Because 2004 FH will be passing so close, it is not practical to include a
detailed ephemeris in this message. Its path across the sky depends greatly
on an observer's vantage point on Earth (owing to the parallax effect).
Observers who wish to locate it in small telescopes should use the MPC's
Ephemeris Service to make detailed predictions for their own geographic
location:
http://cfa-www.harvard.edu/iau/MPEph/MPEph.html
According to the orbit calculated by Gareth Williams, associate director of
the MPC, 2004 FH belongs to the Aten class of asteroids. It circles the Sun
in just under 9 months in very nearly the same plane as Earth's orbit. At
perihelion it swings well inside the orbit of Venus; at aphelion (as
currently) it ranges just outside that of the Earth.
[At time of writing I have not had time to do an epehemeris for Ireland: it
may just be visible from here at, or close to, its time of closest passage,
depending just how far South it goes in Antlia (which lies South of Hydra].
But remember that this object will be moving VERY fast - in only 6 hours it
moves from near Spica to near Sirius! Unless you have very accurate 'GoTo'
your best option is to find an easily recognisable starfield along its
track, point your telescope there with a widefield eyepiece, about 5 minutes
before it is due to pass through that area, and then look for a faint star
gliding across the field. Off the top of my head (no time to do
calculations!), at its closest it will be moving at about 15 arcminutes per
minute of time! That's roughly the diameter of the Moon in 2 minutes. Or
about the diameter of the disc of Saturn per second! So 'live' motion will
be discernable to the eye.
CCD experts can have a go, but you'll need a VERY wide field of view to be
sure of getting it - maybe a telephoto lens, or attach to big binoculars?
Good Luck.
Terry
PS Dr Alan Fitzsimmons (QUB) has just provided this ephemeris for N Ireland
- thanks Alan!
Equatorial coordinates App. motion
Date Hour RA DEC Mag R Delta RA*cosDE DEC
(UTC) h m s d ' " (AU) (AU) "/min "/min
=========== ====== ============= ============ ===== ====== ======= ======== ========
18 Mar 2004 19.000 13 12 19.359 -23 43 34.34 11.2 0.9962 0.0007 -415.8927 -272.8754
18 Mar 2004 19.250 13 4 10.856 -24 55 20.25 11.1 0.9961 0.0006 -476.2974 -301.6714
18 Mar 2004 19.500 12 54 43.776 -26 14 38.87 10.9 0.9961 0.0006 -549.0001 -333.1708
18 Mar 2004 19.750 12 43 40.035 -27 42 6.37 10.8 0.9961 0.0006 -636.9032 -366.6718
18 Mar 2004 20.000 12 30 36.600 -29 18 1.95 10.6 0.9960 0.0005 -743.4452 -400.5237
18 Mar 2004 20.250 12 15 4.349 -31 2 8.77 10.5 0.9960 0.0005 -872.4087 -431.4300
18 Mar 2004 20.500 11 56 27.262 -32 53 1.97 10.4 0.9960 0.0004-1027.2955 -453.4179
18 Mar 2004 20.750 11 34 2.941 -34 47 19.09 10.3 0.9960 0.0004-1209.8388 -456.5689
18 Mar 2004 21.000 11 7 6.596 -36 38 33.09 10.3 0.9959 0.0004-1417.0624 -426.1527
18 Mar 2004 21.250 10 35 2.096 -38 16 5.68 10.2 0.9959 0.0004-1636.6405 -343.9601
18 Mar 2004 21.500 9 57 43.414 -39 24 56.01 10.3 0.9959 0.0003-1842.1953 -194.8827
18 Mar 2004 21.750 9 16 2.743 -39 47 59.29 10.4 0.9958 0.0003-1994.1495 19.9628
18 Mar 2004 22.000 8 32 5.294 -39 11 51.29 10.5 0.9958 0.0003-2053.2145 271.2660
18 Mar 2004 22.250 7 48 43.699 -37 33 38.47 10.7 0.9958 0.0003-2002.6823 507.3472
18 Mar 2004 22.500 7 8 36.809 -35 3 27.99 11.0 0.9957 0.0003-1859.3983 680.9878
18 Mar 2004 22.750 6 33 19.628 -32 0 0.57 11.3 0.9957 0.0004-1661.4703 773.1113
18 Mar 2004 23.000 6 3 17.087 -28 42 56.46 11.7 0.9957 0.0004-1447.0272 793.0371
18 Mar 2004 23.250 5 38 7.880 -25 27 35.48 12.1 0.9956 0.0004-1242.0323 763.3981
18 Mar 2004 23.500 5 17 10.947 -22 23 27.57 12.4 0.9956 0.0004-1059.3734 706.5885
18 Mar 2004 23.750 4 59 42.232 -19 35 9.26 12.8 0.9956 0.0004 -902.9072 638.9347
19 Mar 2004 0.000 4 45 2.219 -17 4 1.84 13.2 0.9955 0.0005 -771.6572 570.3370
19 Mar 2004 0.250 4 32 38.114 -14 49 36.14 13.5 0.9955 0.0005 -662.6252 505.9401
19 Mar 2004 0.500 4 22 3.655 -12 50 30.04 13.8 0.9955 0.0006 -572.3134 447.9268
19 Mar 2004 0.750 4 12 58.114 -11 5 2.29 14.1 0.9954 0.0006 -497.4196 396.8353
19 Mar 2004 1.000 4 5 5.199 - 9 31 30.53 14.4 0.9954 0.0006 -435.0901 352.3818
19 Mar 2004 1.250 3 58 12.070 - 8 8 19.70 14.6 0.9954 0.0007 -382.9632 313.9285
19 Mar 2004 1.500 3 52 8.555 - 6 54 5.37 14.9 0.9953 0.0007 -339.1271 280.7300
19 Mar 2004 1.750 3 46 46.538 - 5 47 34.25 15.1 0.9953 0.0007 -302.0496 252.0547
19 Mar 2004 2.000 3 41 59.490 - 4 47 43.57 15.3 0.9953 0.0008 -270.5074 227.2374
19 Mar 2004 2.250 3 37 42.117 - 3 53 39.93 15.5 0.9952 0.0008 -243.5235 205.6966
19 Mar 2004 2.500 3 33 50.092 - 3 4 38.02 15.7 0.9952 0.0009 -220.3156 186.9351
19 Mar 2004 2.750 3 30 19.849 - 2 19 59.37 15.9 0.9952 0.0009 -200.2541 170.5330
19 Mar 2004 3.000 3 27 8.428 - 1 39 11.33 16.1 0.9951 0.0009 -182.8302 156.1376
19 Mar 2004 3.250 3 24 13.356 - 1 1 46.06 16.2 0.9951 0.0010 -167.6302 143.4536
19 Mar 2004 3.500 3 21 32.548 - 0 27 19.80 16.4 0.9951 0.0010 -154.3156 132.2338
19 Mar 2004 3.750 3 19 4.243 + 0 4 27.81 16.5 0.9950 0.0011 -142.6080 122.2712
19 Mar 2004 4.000 3 16 46.937 + 0 33 54.29 16.7 0.9950 0.0011 -132.2769 113.3918
19 Mar 2004 4.250 3 14 39.344 + 1 1 14.76 16.8 0.9950 0.0012 -123.1304 105.4491
19 Mar 2004 4.500 3 12 40.358 + 1 26 42.31 16.9 0.9949 0.0012 -115.0079 98.3194
19 Mar 2004 4.750 3 10 49.020 + 1 50 28.35 17.0 0.9949 0.0012 -107.7740 91.8979
19 Mar 2004 5.000 3 9 4.500 + 2 12 42.79 17.1 0.9949 0.0013 -101.3140 86.0952
19 Mar 2004 5.250 3 7 26.074 + 2 33 34.35 17.3 0.9948 0.0013 -95.5306 80.8353
19 Mar 2004 5.500 3 5 53.108 + 2 53 10.65 17.4 0.9948 0.0014 -90.3403 76.0528
19 Mar 2004 5.750 3 4 25.046 + 3 11 38.43 17.5 0.9948 0.0014 -85.6714 71.6917
19 Mar 2004 6.000 3 3 1.399 + 3 29 3.65 17.6 0.9947 0.0014 -81.4620 67.7035
19 Mar 2004 6.250 3 1 41.737 + 3 45 31.56 17.7 0.9947 0.0015 -77.6583 64.0464
19 Mar 2004 6.500 3 0 25.680 + 4 1 6.87 17.8 0.9947 0.0015 -74.2137 60.6839
19 Mar 2004 6.750 2 59 12.888 + 4 15 53.74 17.8 0.9946 0.0016 -71.0872 57.5843
19 Mar 2004 7.000 2 58 3.065 + 4 29 55.90 17.9 0.9946 0.0016 -68.2428 54.7200
19 Mar 2004 7.250 2 56 55.946 + 4 43 16.71 18.0 0.9946 0.0016 -65.6489 52.0666
19 Mar 2004 7.500 2 55 51.293 + 4 55 59.16 18.1 0.9945 0.0017 -63.2775 49.6029
19 Mar 2004 7.750 2 54 48.900 + 5 8 5.96 18.2 0.9945 0.0017 -61.1038 47.3102
19 Mar 2004 8.000 2 53 48.580 + 5 19 39.53 18.2 0.9945 0.0018 -59.1058 45.1717
19 Mar 2004 8.250 2 52 50.168 + 5 30 42.10 18.3 0.9944 0.0018 -57.2636 43.1730
19 Mar 2004 8.500 2 51 53.518 + 5 41 15.64 18.4 0.9944 0.0018 -55.5597 41.3009
19 Mar 2004 8.750 2 50 58.500 + 5 51 21.97 18.5 0.9944 0.0019 -53.9784 39.5440
19 Mar 2004 9.000 2 50 5.000 + 6 1 2.75 18.5 0.9943 0.0019 -52.5055 37.8919
19 Mar 2004 9.250 2 49 12.916 + 6 10 19.47 18.6 0.9943 0.0020 -51.1282 36.3357
19 Mar 2004 9.500 2 48 22.159 + 6 19 13.51 18.7 0.9943 0.0020 -49.8351 34.8670
19 Mar 2004 9.750 2 47 32.651 + 6 27 46.12 18.7 0.9943 0.0020 -48.6159 33.4785
19 Mar 2004 10.000 2 46 44.323 + 6 35 58.47 18.8 0.9942 0.0021 -47.4614 32.1639
19 Mar 2004 10.250 2 45 57.114 + 6 43 51.62 18.9 0.9942 0.0021 -46.3631 30.9171
19 Mar 2004 10.500 2 45 10.974 + 6 51 26.53 18.9 0.9942 0.0022 -45.3137 29.7331
19 Mar 2004 10.750 2 44 25.857 + 6 58 44.12 19.0 0.9941 0.0022 -44.3062 28.6069
19 Mar 2004 11.000 2 43 41.725 + 7 5 45.23 19.1 0.9941 0.0022 -43.3346 27.5346
