To put the latest images of 2011 W3 into some sort of real perspective as
to just what sort of object we are dealing with, I would point out that at
the comet's current heliocentric distance Comet Ikeya-Seki was already as
bright as 2nd magnitude and displaying a faint gas tail over ten degrees in
length photographically! Let's all keep in mind that 2011 W3 is no more than
a tiny cometary shard and apparently some 7 full magnitudes (!) fainter
than Ikeya-Seki was intrinsically.

Likewise, as I believe I briefly alluded to earlier, the post perihelion
survival figure needed for a comet's absolute magnitude, one with a
perihelion distance of only 0.005 AU, would be essentially ~7.0 . Comet 2011 W3
appears to have a value close to 13.5 , based on the latest V magnitudes.
Therefore, there should be zero possibility of the comet lasting beyond
perihelion passage as any sort of coherent body. It could potentially not even
make it to perihelion!

Back a number of posts ago a question was raised about the arrival of 2011
W3 perhaps potentially heralding the arrival of a swarm of other pygmy
sungrazers, or perhaps even a major sungrazer. The answer would seem to be
that 2011 W3's arrival is just another in the almost steady flow of pygmy
sungrazers observed for decades now. If anything, the brilliant object that was
caught by SOLWIND in 1979, only 9 years following Comet
White-Ortiz-Bolelli, might have been take to signify something. It didn't.

Dave posed the interesting question about could there be any possibility
of 2011 W3 having a revolution period as short as 170 years and therefore
being a fragment from the Great Comet of 1843? I, too, read somewhere that
one of the SOHO comets seemed to have an orbital period of ~170 years.
However, let's not forget that such an orbit was based on no more than just a 2
day arc of astrometric observations! That doesn't instill me with much
confidence.

Since virtually all the observed secondary nuclei of the major sungrazers
have moved decidedly tailward after separation their parent and the tiny
"satellite comets" seen by Barnard and others in 1882 were similarly situated
anti-solar of the major nuclei, it would appear that such bodies always
have much LONGER orbital periods than does the surviving parent object.

Shortly I'll be posting more concerning just how difficult it is to predict
what even might be seen via SOHO and other space craft as 2011 W3
approaches its perihelion. And also just how unusually brief great brilliance in
sungrazers is and how this tricked, or mislead, observers back in 1965.

J.Bortle







In a message dated 12/8/2011 7:54:01 A.M. Eastern Standard Time,
janebr@... writes:




R and V composites from our today's data by our friend Michal (I actually
have no idea what it last name is, I am sorry)

_http://img11.imageshack.us/img11/7299/krv1.jpg_
(http://img11.imageshack.us/img11/7299/krv1.jpg)

In R the tail is particularly pronounced, whereas in V the coma is bigger.

Cheers,
Jan

--- In _comets-ml@yahoogroups.com_ (mailto:comets-ml@yahoogroups.com) ,
"terryjlovejoy" <terryjlovejoy@...> wrote:
>
> This is great news! please post an image when you can.
>
> --- In _comets-ml@yahoogroups.com_ (mailto:comets-ml@yahoogroups.com) ,
"opisska" <janebr@> wrote:
> > Best regards,
> > Jan Ebr
> >
> > PS: I have just downloaded today's data, the comet seems even brighter
and the tail is more developed
> >
>






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