(meteorobs) Circular IAU C22 Pro-Amat WG: Possible meteors from comet P/2005 JQ5 (Catalina)

[Mikhail Maslov]

Hello, Peter and all,

Many thanks for your two letters and for your study with Esko
Lyytinen. I'm sorry, I'm quite busy these days, so just now I make
comments on P/2005 JQ5 Catalina. Some time later I'll try to respond
to other messages.
As I understand, the comet P/2005 JQ5 Catalina was not known before
its apparition in 2005 (or it was?, under some other designation,
for example?). And, as we know, comets and meteor particles are
subjected to non-gravitationnal forces. Some of them are quite
regular, for example radiation pressure. But comet's trajectory is
also influensed by non-regular reactive forces due to dust and vapor
jets they release when they are not very far from the Sum. A given
comet have to be observed at least at several apparitions before some
approximate characteristics of these jet forces can be defined. So
far, we can't compute comet movement during many centures on the base
of only one apparition, as in P/2005 JQ5 Catalina case. In meteor
computations accurate orbital elements of parent comet are extremely
important. Say, an error in perihelion date even of several days can
completely crash the results and lead to totally wrong conclusions. If
we don't know the influence of non-gravitational forces, such an error
can easily appear in the computation of secular comet movement.
About future evolution of P/2005 JQ5 Catalina. As follows from the
latest orbit, obtained on the broader observed arc, during the period
of 1901-2100 minimal distance between comet and Earth orbit is to be
gradually decreasing from 0.05 AU in the beginning of 20 century to
0.0244 AU in 2005 and to 0.01 AU to the end of 21 century. Perhaps in
22 century these orbits will intersect each other. In 2005 the minimal
distance corresponds to sol.long=82.207 deg. (13.06.2005 4:37 UT).
During 21 century longitude of min. dist will also decrease from 79-83
deg. in its first half to 76-81 deg. in the second.
And the last on this comet. It is very small. For example, if comet
21P Giacobiny-Zinner had such size, in 1946 instead of storm of many
thousands meteors per hour the world would see no more than several
dozens meteors per hour. I think, it decreases meteor abilities of
P/2005 JQ5 Catalina very much. Say, if in case of Draconid activity we
could see an outburst of 100 meteors per hour or lower, the same dust
trails geometry with P/2005 JQ5 Catalina as a parent comet gives
almost nothing, below visual recognizing. If it was on the place of 7P
Pons-Winnecke, we would see nothing in 2004 and nothing or almost nothing in
1998. But, maybe this a comet produces relatively high number of
very small particles and can be the source of radio-shower. Some
radioreports on meteorobs inform about increased number of signals
on 12 June. This is very interesting On the other hand, slow meteors,
as I know, are difficult to observe on radiowaves.

Best regards, Mikhail Maslov




PJ> CIRCULAR FROM THE PRO-AMAT WORKING GROUP OF IAU C-22
PJ> June 16,2005
PJ> ==============================================================

PJ> POSSIBLE METEORS FROM COMET P/2005 JQ5 (CATALINA)

PJ> It was first pointed out by Mikhail Maslov (meteorobs) 
PJ> that comet
PJ> P/2005 JQ5 does not pass far from Earth orbit and may 
PJ> cause meteor
PJ> activity. He found that the current elements put the 
PJ> radiant at
PJ> RA=242 deg, Dec=-09 deg, and any meteors from this radiant 
PJ> would
PJ> be very slow (Vg=16 km/s).

PJ> A study by Esko Lyytinen and Peter Jenniskens now shows 
PJ> that
PJ> most recent dust trails from this comet (particularly 
PJ> those of 2005
PJ> and 1948)  are well within Earth orbit and are not 
PJ> expected to cause
PJ> noticeable activity. However, dust ejected around 
PJ> 1300-1400 A.D.
PJ> may have wandered in Earth's path as a very dispersed 
PJ> stream
PJ> between June 14 and June 24. In particular, Esko evaluated 
PJ> the
PJ> trails 1302, 1350, 1403, and 1500 A.D. to find that all 
PJ> accumulate
PJ> at around the same range of solar longitude, with the 
PJ> comet orbit
PJ> not changing much over that timeframe.

PJ> For the period June 14 - June 24, a low level of activity 
PJ> may radiate
PJ> from (for June 17.0)  RA = 244.3, Decl. = -9.9 (J2000.0) 
PJ> with
PJ> Vinf = 19.05 km/s (or Vg = 15.44 km/s).

PJ> This is near the star psi-Scorpii, just above the ecliptic 
PJ> plane
PJ> and near the antihelion source direction. To discriminate 
PJ> from sporadic
PJ> meteors, orbits may need to be determined. A test 
PJ> particles from
PJ> the 1302 trail near Earth orbit at the current Epoch was 
PJ> found to
PJ> have orbital elements:

PJ> a = 2.76 AU
PJ> q = 0.8417 AU
PJ> Node = 86.067 degrees (J2000.0)
PJ> w = 233.79 degrees
PJ> i = 4.94 degrees

PJ> It is not known if this comet was active that long ago, 
PJ> nor how much
PJ> dust it may have ejected. Hence, any predictions of meteor 
PJ> activity
PJ> will be unreliable. We surmise that the activity will be 
PJ> low and dispersed
PJ> over a ten-day period.

PJ> When the comet is near Earth in 2085, the dust ejected in 
PJ> the
PJ> return of 2005 will also be close to Earth path that year 
PJ> and the
PJ> shower may be more prominent.

PJ> -Peter Jenniskens

PJ> Chair Pro-Amat Working Group IAU C-22
PJ> ---
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