[AZ-Observing] Martian Cepheids/Comet Wiseman-Skiff
- From: Brian Skiff <Brian.Skiff@xxxxxxxxxx>
- To: az-observing@xxxxxxxxxxxxx
- Date: Thu, 2 Jun 2005 22:33:47 -0700 (MST)
This one seems to be spreading fast on the Web; our PR guy asked
whether I could supply a quote. This was indeed found by Jennifer Wiseman,
an MIT undergrad at the time. Each January we host a group of MIT students
working on geophysics/planetary science degrees. On this occasion (18 years
ago!), the Moon was going to be bright during their stay, so I took
a bunch of plates (this is back in the days when the observing was done
with the Pluto Camera) over the holidays that we saved for a student
to scan on our blink machine. Well, the first morning we set Jennifer
to work, showing her some known asteroids on a plate-pair so she'd
know what to look for and how to mark them. We left her alone and went
back to our offices. Within half an hour she was back saying apprehensively
that we better come have a look because she found this very fuzzy asteroid....
This immediately presented a problem since it had been three weeks
since the plates were taken, and there would be no announcement without
a second night. There was no cadre of amateurs around the world as there is
now who could do the follow-up, so it was up to us. Ted Bowell made the
best prediction he could (again, much less sophisticated than could be
done now with the same data), and Jennifer and I went out the same night
and got some more plates in hopes of the best. We came right back to
Mars Hill, developed the plates (an unanticipated lesson for Jennifer about
darkroom procedure), and put them on the blink comparator. It was "only"
a degree and a half off target, well within the 6x9-deg field of the Pluto
Camera plates.
Jennifer was a final-semester senior at the time, and had not come up
with a (required) thesis project, much less actually done anything about it;
this of course was a big load off her mind in one swell foop (she did some
additional observations back in Massachusetts in the ensuing months).
I remember sitting as we measured the plates on our PDS machine (scanning
microdensitometer), and her asking the professor Jim Elliot (who was here this
week with the latest summer students) whether she could get her degree now.
Since Bruce M is interested in this sort of thing, I'll note that
the comet was significantly perturbed by Jupiter in 1984, which upped the
eccentricity and reduced the perihelion distance to about half what it
had been previously---which made it brighter and easier to discover!
The implication thus is that the Martian Cepheid meteor shower now associated
with the comet is a recent start-up. If you visit the JPL orbit page
for the comet:
http://neo.jpl.nasa.gov/cgi-bin/db_shm?sstr=114P
...you can see that the orbit-intersection distance is no more than the
width of the lines used to show the path of Mars and the comet (something I
hadn't known before this morning). The non-trivial encounters with Jupiter
are still there, too, which I assume dominates things (the comet is in a
typical 3:2 Jupiter resonance now), but clearly further perturbations are
likely over the long term.
The old IAU Circulars seem to be publicly available, so you can
read the discovery announcement and follow-up:
http://cfa-www.harvard.edu/iauc/04200/04299.html
http://cfa-www.harvard.edu/iauc/04300/04301.html
The second of these has another night of observations by Jennifer with
S. J. 'Bobby' Bus (Bobby is the person who first showed Carolyn Shoemaker
how to use the Palomar 18-inch Schmidt, and you know what _that_ led to).
I've been in touch today, too, with Jennifer (now at NASA Headquarters),
and she's once again just amazed: "gawd, now we're crashing into Mars!"
Considering the hundreds of Comet LINEARs out there, to me the amazing thing
is the long odds of it being our comet that produced the meteor.
Among the Web resources I've seen, there's a good one at the site of
one of the institutions involved:
http://www.obspm.fr/actual/nouvelle/jun05/meteor.en.shtml
(Francophones change 'en' to 'fr')
\Brian
--
See message header for info on list archives or unsubscribing, and please
send personal replies to the author, not the list.
Other related posts:
- » [AZ-Observing] Martian Cepheids/Comet Wiseman-Skiff
