[Prev][Next][Index][Thread]
(meteorobs) Excerpt from "CCNet 1/2001 - 3 January 2001"
The item below was of some interest to observers who plot meteors visually
or telescopically - and thus may on occasion be able to observe very minor,
previously unknown showers. Has anyone done the formulae to determine the
possible radiant position & drift for meteors from this outbursting comet?
Clear skies and maybe a couple of "TGKids", :)
Lew Gramer
------- Forwarded Message
From: Benny Peiser <B.J.Peiser@livjm.acdot uk>
To: cambridge-conference <cambridge-conference@livjm.acdot uk>
Subject: CCNet 3 January 2001
Date: Wed, 3 Jan 2001 10:42:57 -0000
CCNet 1/2001 - 3 January 2001
-----------------------------
[...]
(3) OUTBURST OF COMET TUTTLE-GIACOBINI-KRESAK=20
NearEarthdot net=20
============================================================
(3) OUTBURST OF COMET TUTTLE-GIACOBINI-KRESAK
>From NearEarthdot net
http://meteors.com/cometlinear/a_normally_small.html
By Dr Mark Kidger
A normally small and faint comet called 41P/Tuttle-Giacobini-Kresak is
currently suffering a huge outburst and has reached binocular =
visibility
at magnitude 8 and even threatens to become brighter than Comet
McNaught-Hartley. First seen in 1858, this comet will reach perihelion
on January 6th. The orbital period is 5.43 years, one of the shortest
known. What makes the comet interesting is the fact that it's =
perihelion
distance is only just the Earth's orbit and the orbit is only slightly
inclined, so the comet can occasionally come very close to the Earth =
but
remaining near opposition and thus extremely well placed to observe in
the sky.
On this occasion the comet's apparition is a rather poor one. The
closest approach to the Earth, around Christmas Day, is at 225 million
kilometres and the comet was now expected to get as bright even as
magnitude 11. At the end of the first week in December the light curve
was behaving as expected. The comet was around magnitude 11.5 and not
particularly interesting. A week later though it was suddenly three
magnitudes brighter. An observation by the Australian comet observer
Andrew Pearce, made on December 18th, showed the comet to be magnitude =
8
and apparently still rising in brightness. The comet seems to have
brightened still further since then; on December 20th two Czech
observers estimated it at close to magnitude 7.5, although the previous
night an Australian and a Brazilian observer had found the comet to be =
a
full magnitude fainter, albeit with moonlight interfering.
You can find a light curve of the comet from Japanese observations =
here.
At present the comet is in Virgo and a morning object only 45 degrees
from the Sun although it attains a reasonable altitude in the sky =
before
dawn. It may brighten further still. Over the next few weeks the comet
will maintain an almost constant position relative to the Earth in its
orbit and thus will stay at an almost constant distance from the Sun in
the sky and at an almost constant distance from the Earth. Any further
brightening will indicate that the outburst is still continuing.
Nobody actually knows what causes outbursts in comets. There are many
theories. Certainly, in some cases they are due to a fragmentation of
the nucleus. In others all we see is that a large dust and gas cloud is
suddenly expelled for no readily apparent reason. This may be due to
small eruptions, not unlike volcanic activity, on the surface of the
nucleus, where a small pocket of volatile ice suddenly sublimes and
breaks through the crust on the nucleus leading to a small explosion of
gas that blows dust and ice out into space. Many eruptions though take
place at great distance from the Sun where such violent sublimation is
not expected to occur.
--------------------------------------------------------------------
THE CAMBRIDGE-CONFERENCE NETWORK (CCNet)
--------------------------------------------------------------------
The CCNet is a scholarly electronic network. To subscribe/unsubscribe,
please contact the moderator Benny J Peiser <b.j.peiser@livjm.acdot uk>.
Information circulated on this network is for scholarly and educational
use only. The attached information may not be copied or reproduced for
any other purposes without prior permission of the copyright holders.
The fully indexed archive of the CCNet, from February 1997 on, can be
found at: http://abob.libs.ugadot edu/bobk/cccmenu.html
DISCLAIMER: The opinions, beliefs and viewpoints expressed in the
articles and texts and in other CCNet contributions do not necessarily
reflect the opinions, beliefs and viewpoints of the moderator of this
network.
------- End of Forwarded Message
To UNSUBSCRIBE from the 'meteorobs' email list, use the Web form at:
http://www.tiacdot net/users/lewkaren/meteorobs/subscribe.html