* Astronomy

Asteroid (3200) Phaethon makes its closest approach to the Earth (0.873 AU) on the 2nd May, 2012.

Ephemeris

Date    TT    R. A. (2000) Decl.     Delta      r     Elong.  Phase     V
2012 05 02    02 41 07.2 +13 00 47   0.8737  0.1404     2.5   161.6    21.6
2012 05 03    02 28 40.3 +13 22 17   0.8802  0.1427     3.8   151.7    18.9
2012 05 04    02 17 54.5 +13 56 39   0.9011  0.1570     6.9   129.5    16.0
2012 05 05    02 09 50.5 +14 38 18   0.9311  0.1796     9.6   110.7    14.9
2012 05 06    02 04 18.3 +15 22 23   0.9651  0.2066    11.7    96.3    14.5
2012 05 07    02 00 43.9 +16 06 11   1.0001  0.2357    13.5    85.4    14.5
2012 05 08    01 58 35.5 +16 48 27   1.0349  0.2654    14.9    77.1    14.5
2012 05 09    01 57 28.9 +17 28 45   1.0686  0.2951    16.0    70.6    14.6
2012 05 10    01 57 07.1 +18 06 59   1.1011  0.3245    17.0    65.3    14.7
2012 05 11    01 57 18.3 +18 43 13   1.1323  0.3534    17.8    61.1    14.8
2012 05 12    01 57 54.0 +19 17 35   1.1621  0.3816    18.6    57.6    14.9
2012 05 13    01 58 48.2 +19 50 14   1.1908  0.4093    19.3    54.6    15.0
2012 05 14    01 59 56.5 +20 21 17   1.2182  0.4363    19.9    52.1    15.1
2012 05 15    02 01 15.6 +20 50 54   1.2446  0.4627    20.5    49.9    15.3
2012 05 16    02 02 43.2 +21 19 12   1.2699  0.4885    21.1    48.1    15.4
2012 05 17    02 04 17.3 +21 46 16   1.2943  0.5137    21.6    46.4    15.5
2012 05 18    02 05 56.6 +22 12 14   1.3178  0.5384    22.1    45.0    15.6
2012 05 19    02 07 39.8 +22 37 11   1.3403  0.5626    22.6    43.8    15.7
2012 05 20    02 09 26.1 +23 01 10   1.3621  0.5863    23.1    42.6    15.8
2012 05 21    02 11 14.9 +23 24 17   1.3832  0.6095    23.6    41.6    15.9
2012 05 22    02 13 05.5 +23 46 36   1.4034  0.6322    24.1    40.7    15.9
2012 05 23    02 14 57.4 +24 08 09   1.4230  0.6545    24.5    39.9    16.0

3200 Phaethon was discovered in 1983 by NASA's IRAS satellite and promptly classified as an asteroid. What else could it be? It did not have a tail; its orbit intersected the main asteroid belt; and its colours strongly resembled that of other asteroids. Indeed, 3200 Phaethon resembles main belt asteroid Pallas so much, it might be a 5-kilometer chip off that 544 km block.
Researchers have looked carefully at the orbits of Geminid meteoroids and concluded that they were ejected from 3200 Phaethon when Phaethon was close to the sun - not when it was out in the asteroid belt breaking up with Pallas. The eccentric orbit of 3200 Phaethon brings it well inside the orbit of Mercury every 1.4 years. The rocky body thus receives a regular blast of solar heating that might boil jets of dust into the Geminid stream.
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The magnitude 14.5 asteroid 3200 Phaethon will pass 0.58 from the open cluster NGC 6507 in the constellation Sagittarius, at 13:00 UT, 4th December, 2010.

An asteroid that is the source of an annual meteor shower may owe its weird crumbliness to intense cooking by the sun.
Most meteor showers are thought to come from comets, whose icy surfaces vaporise easily during close encounters with the sun. Dust that is liberated in the process burns up in Earth's atmosphere, creating "shooting stars".
However, the debris stream responsible for the annual Geminid shower in December follows the orbit of a 5-kilometre-wide object called 3200 Phaethon, which appears to be an asteroid.
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