Periodic comet 73P/Schwassmann-Wachmann 3 has broken into more than 30 different pieces as it approaches the sun. This comet was discovered on 1930 May 2 by Arnold Schwassmann and Arno Wachmann at the Hamburg (Germany) observatory. It was the third periodic comet discovered by this pair and the 73rd comet to be recognized as periodic.
Because of poor observing conditions, the comet was not recovered during its next return to perihelion in 1935-36. As a result, the comet’s preliminary orbit was rough and the comet’s close passes by Jupiter in 1953 October (0.9 AU) and 1965 November (0.25 AU) further degraded the orbital predictions. One Astronomical Unit (AU) is about 93 million miles. The comet was re-discovered on Aug. 13, 1979, missed during the next return to perihelion in 1985-86 – again because of poor observing conditions - and then observed during its returns in 1990, 1995-96, 2000-2001, and the current 2005-2006 return. In late 1995, the comet began to breakup into various fragments. The main comet (fragment C) was seen to give rise to two new fragments, A and B.
In 2001, the main comet (fragment C) was observed along with the old fragment B and a new fragment E.
During the 2006 return to perihelion, which for the main fragment C takes place on 2006 June 6 (just inside the Earth’s orbit), the comet began to fragment into more than 30 additional pieces. All of the observed fragments in 2006 will pass relatively close to the Earth during the interval May 12 through May 28 but none will pass closer than 5.5 million miles. These passages of the fragments past the Earth offer astronomers an excellent opportunity to examine the cometary breakup process and hopefully these observations will shed some light on just why some comets disrupt. Apparently some comets have very weak internal structures and perhaps rapid rotation or the pressure of vaporizing interior ices, as the comet approaches the warming sun, causes these breakup events.
In addition to ongoing ground-based visual observations, the Hubble Space Telescope and the Spitzer infrared space telescope are continuing to observe the comet and the Arecibo and Goldstone planetary radars will begin observations on April 30, 2006.
Animated gif from the Cordell-Lorenz Observatory: Brighter new component of Comet 73P about 90 arc minutes East of the rest of the components C, AF, and AP. Stacks of 40 thirty second long exposures added with a motion vector of 4.25 "/min at PA 79 degrees. Object moves in front of a group of stars near mid-frame, but can be clearly seen.
This sky map shows how the position of Comet Schwassmann-Wachmann 3 shifts over one-week intervals, as seen in eastern skies as of 1 a.m. local time from mid-northern latitudes
This false-colour view shows three distinct fragments of Comet Schwassmann-Wachmann 3 after its break-up — produced by the European Southern Observatory's New Technology Telescope in Chile on Jan. 31, 1996.
On Apr. 11 the comet had a visual magnitude of 8.8, and it will brightened steadily. On May 12 it will pass only 0.0786 A.U. from the earth , and should be a naked eye object.
In 1995, Comet 73P/Schwassmann-Wachmann 3 did something unexpected: it fell apart. For no apparent reason, the comet's nucleus split into at least three "mini-comets" flying single file through space. Astronomers watched with interest, but the view was blurry even through large telescopes. "73P" was a hundred and fifty million miles away.
We're about to get a much closer look. In May 2006 the fragments are going to fly past Earth closer than any comet has come in more than twenty years.
Fragments B and C approaching Earth on Feb. 26, 2006. Credit: Giovanni Sostero and Ernesto Guido of the Remanzacco Observatory in Italy using a remote-controlled 14-inch telescope in New Mexico.
Title: The t Herculid meteor shower and Comet 73P/Schwassmann–Wachmann 3 Author: P. A. Wiegert, P. G. Brown, J. Vaubaillon and H. Schijns
ABSTRACT The t Herculid meteor shower has not shown any appreciable activity since 1930. However, it is associated with Comet 73P/Schwassmann–Wachmann 3, a Jupiter-family comet that split in 1995. The fragments will pass near the Earth on 2006 May 13, and could produce an outburst of the t Herculid shower. However, by considering both meteoroids released during the splitting event and on previous perihelion passages back to 1801, we find no evidence for enhanced activity from this shower in 2006. This is a result partly of the dynamics of the parent comet, which suffers frequent close encounters with Jupiter, and partly of the location and timing of the splitting event, which produces a distribution of meteoroids that does not approach the Earth particularly closely. In fact, we show that the 1930 observations date from one of the few expected appearances of the t Herculid shower and predict that detectable activity will be produced in 2022 and 2049.
The periodic comet 73P/Schwassmann-Wachmann 3 with an orbital period of 5.43 to 5.46 will pass 0.0786 AU from the earth on May 12th, 2006. The comet was discovery in 1930. It is expected to be visible to the naked eye. Currently it is at magnitude 11.9 with a condensed nucleus. During the last observed return on August 19, 1995 at magnitude 12.9 the comets brightness increased by 6 magnitudes in the beginning of October, due to the nucleus breaking apart into three main nuclei.
It will be visible in the Northern Hemisphere in May. The comet is connected to the Tau Herculids meteor shower which was also observed in 1930. The meteor shower may show increased activity this year during May 19 to June 19. The maximum occurs on June 9, from an average radiant of RA = 236 deg, Dec = +41 deg. The source of the June Bootids is the periodic comet 7P/Pons-Winnecke.