Table of brightest asteroids for 2009 Close approaching asteroids
The Asteroids, also known as Minor Planets, are small "planets" orbiting the Sun, mostly between Mars and Jupiter. The largest, Ceres, has a diameter of about 933 km, most are much smaller. Over hundred thousand have had their orbits described, but only a few of the larger ones are bright enough to be picked up in binoculars. Mostly this will be only for a month or two either side of opposition, that is when the asteroid is on the opposite side of the Earth to the Sun. It is then at its closest to the Earth and is also fully lit by the Sun as seen from the Earth.
Details are given of the asteroids which reach an opposition magnitude 9.0 or brighter during 2008. At this magnitude an object should be visible in 50 mm aperture binoculars from a dark site, with clear skies and without too much Moon light.
For each asteroid a chart is included showing its path. The charts show stars to magnitude 9.5 and each has a circle on it representing a 5° field. This is a typical field for 8x50 or 10x50 binoculars. In addition there is a table showing the position (right ascension and declination) of the asteroid at 10 day intervals while it is at magnitude 9.5 or brighter.
Charts are for the southern hemisphere with south at the top and east to the right. Anyone using a chart in the northern hemisphere would need to turn it upside down. The charts would give a "true" view when the asteroid is due north. When to the east or west, the sky would appear to be rotated, clockwise if to the east and anticlockwise when to the west, as seen from the southern hemisphere.
The table below lists all asteroids which meet the criterion of magnitude at their opposition in 2008. The magnitude given is that at opposition, which is usually when the asteroid is at its brightest.
For further details of asteroids visit the JPL small-body database browser.
| Asteroid | Opposition date | Magnitude | Range of dates brighter than 9.5 |
|---|---|---|---|
| (27) Euterpe | 2009 February 4 | 8.8 | 2009 January 8 to February 25 |
| (1) Ceres | 2009 Feb 25 | 6.9 | At all times |
| (14) Irene | 2009April 21 | 8.9 | 2009 March 15 to May 23 |
| (7) Iris | 2009 July 4 | 8.7 | 2009 June 4 to August 13 |
| (3) Juno | 2009 September 22 | 7.6 | 2009 July 9 to 2010 February 9 |
| (18) Melpomene | 2009 October 9 | 7.9 | 2009 July 25 to December 23 |
| (4) Vesta | No opposition in 2009 | At all times | |
| (2) Pallas | No opposition in 2009 | Throughout 2009 | |
The closest approach was on Mar 9, when an asteroid designated 2008 EF32 passed at a distance of 0.0005279 AU, that is just under 80 000 km, 20% of the Moon's distance. The next closest was on February 5, at a distance of .0009AU, a little over 100 000km.
The closest approach of an asteroid predicted for future years is on 13 April 2029 (14 April in NZ),when (99942) Apophis will pass at about 35000km, one-tenth of the distance of the Moon. This may well be bright enough to be briefly visible by eye. Unfortunately for NZ its time of closest approach is estimated to be about 10 am.
A 33 year list of predicted close approaches can be found at a Harvard IAU site.