Naked Eye Comet Next Summer?

www.aerith.net/comet/catalog/0073P/2006.html

Hi all

Things might get very interesting next year. Comet 73P Schwassmann - Wachmann 3 at the present time as split into 3 seperate fragmnets. The good news?..if magnitude predictions hold true then this comet may peak at magnitude 2 in the May/June summer period of 2006. That will be the brightest comet since Hale -Bopps apparition in 1997. In the same period fragment B will reach magnitude 6 -7 and fragment C at magnitude 8-9.

All of this is still preliminary but by next year we will have a great chance to image/observe and sketch a bright comet in our skies....get prepared!

Fingers crossed.

Hi Martin.

While personally I don't think it'll get that bright, given the notorious uncertainties of predicting how bright comets will become (the late comet observer Harold Ridley used to compare predictions of comet brightnesses to picking a winner in horse racing!) and the fact the split occured about 10 years ago (with one intervening perihelion passage since), the very close encounter we'll see will probably make it a naked-eye object, and will no doubt be spectacular telescopically. I've pasted the notes on 73P from Jon Shanklin's BAA Comet Section guide for 2006 as a guide to what we we should expect - it's quite possible we'll see a meteor shower outburst as well.

Brian

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Professor Arnold Schwassmann and Artur A Wachmann of Hamburg Observatory discovered their third periodic comet on minor planet patrol plates taken on 1930 May 2. Initially of magnitude 9.5 it brightened to nearly 6m, thanks to a very close approach to Earth (0.062 AU) on June 1. The initial orbit was a little uncertain and the comet wasn’t found at the next or succeeding apparitions until 1979. The comet passed within 0.9 AU of Jupiter in 1953, and 0.25 AU in 1965. In August 1979, Michael Candy reported the discovery of a comet on a plate taken by J Johnston and M Buhagiar while searching for minor planets; this had the motion expected for 73P/Schwassmann-Wachmann, but with perihelion 34 days later than in a prediction by Brian Marsden. Missed again at the next return, it has been seen at the last three returns. At the 1995 return the comet underwent a major outburst near perihelion, reaching 5m when it was only expected to be 12m. Subsequently four components were observed, though calculations by Sekanina suggested that the fragmentation occurred after the outburst. Three fragments were recovered in 2001, but only a few visual observations were reported as the comet was poorly placed and the absolute magnitude had clearly faded a little from the previous return. The components have now separated in the date of perihelion by roughly a day.



The comet's 1930 approach to Earth is currently ninth on the list of well-determined cometary approaches to our planet. In May the fragments will make another close approach, when the brightest one could again reach 7m or brighter, possibly even becoming visible to the naked eye. The encounter circumstances are favourable for the UK. At closest approach the fragments will be racing across the sky at around 4.5° a day, though they are separated by around ten degrees from each other. Their exact paths across the sky will only be determined after recovery due to uncertainties in the non-gravitational parameters for each fragment and the extremely close approach. The main fragment (C) is currently predicted to pass at 0.073 AU on May 13.22 when it is in Vulpecula. The other fragments (B and E) will follow it, approach closer and be further north in the sky (May 14.60, 0.065 AU; May 17.32, 0.052 AU); the pass of fragment E will replace the 1930 pass as the 9th closest cometary encounter and the other two will be 12th and 14th closest. After the encounter they rapidly head south and will be difficult to observe a week later.



With the orbit approaching so closely to the Earth, an associated meteor shower might be expected, and the comet has been linked to the Tau Herculid shower, though the radiant now lies in the Bootes - Serpens region. Strong activity was reported in 1930 by a lone Japanese observer, but little has been seen since then. It is likely that any future activity would be in the form of a short-lived outburst, confined to years when the comet is at perihelion.


There are several close cometary approaches in the 2nd decade of the 21st century. Three feature comets at perihelion this year, with 41P/ approaching to 0.135 AU in 2017, in addition to the approaches of 45P/ already mentioned. There are five others, with 2000 G1 passing at only 0.032 AU in 2016 (4th closest) and 2004 CB passing at 0.051 AU in 2014 (9th closest). The brightest pass is that of 46P/Wirtanen, which may be a circumpolar object of 3rd magnitude over Christmas 2018, when it passes 0.076 AU at mid month.

hi Martin/Brian,

should be great view of 73P if the fragments do brighten significantly when close to Earth. It'll be nice to see their (relatively) rapid motion across sky anyway.

re: the Tau Herculids, a recent paper considered that because the comet fragmented out near Jupiter then there is only a very low chance of a meteor storm from 73P when near Earth.

here's a piece on the Tau Herculids culled from the meteor diary I've written for the upcoming IAS publication Sky-High 2006 (to be available at the WSP I believe).

(the IMO meteor shower calendar for 2006 is also available now on www.imo.net

A special note must be made though of the Tau Herculids, a minor shower which has a month long period of activity from May 19th to June 19th with maximum on June 9/10.

The Tau Herculids are associated with Comet 73/P Schwassmann Wachmann 3 (SW3) which was observed to split in 1995. The comet returns to perihelion in 2006 and it’s fragments pass close to Earth in mid-May leading to the possibility that this will yield enhanced Tau Herculid rates.

However, a recent paper in the journals considered the circumstances of the 1995 break up of SW3. The authors found that the ribbon of meteoroid material may not approach the Earth as closely as we’d hope due to the subsequent gravitational influence of Jupiter on the new stream.

If we do see anything we will really only have a one hour period of dark — if you could call it that in June’s perpetual twilight — as moonset is not until 02h on the morning of June 10th. The meteors are rather faint too and the radiant — now in the Boötes-Serpens region of the sky — is getting lower in the west approaching dawn. All reports of increased numbers of meteors around this time are extremely valuable and should be submitted to the International Meteor Organisation ( www.imo.net ).

atb,

John[/url]

Thanks for the great info John and Brian. I know that comets are very unpredicatable beasts but if fragment C arrives anywhere near its predicted magnitude then it should still be a good show. Seeing an increase in meteor activity (if we do) will be an added bonus...i guess we will have to wait and see what nature does! If you here of any more info regarding this comet please post it here.

Thanks