Occultation of SAO 78190 by (22) Kalliope and its satellite Linus, 2006 November 7
- New Nov. 8
These are the first well-confirmed observations of an occultation by an
asteroidal satellite
The fact that an occultation by Linus would be visible from Japan was
predicted by Jerome Berthier at IMCCE in Paris, France about a day in advance
We hope that this will encourage more observers to monitor close
appulses to try to find and confirm occultations by satellites of
other asteroids
Message sent by Dr. Mitsuru Soma, Japanese National Astronomical
Observatory, to the Central Bureau for Astronomical Telegrams (CBAT)
Date: Wed, 08 Nov 2006 20:48:37 +0900
To: "CBAT"
From: "Mitsuru SOMA"
Subject: successful occultation by Linus
CC: "Sendai-uchukan"
Dear Sirs,
The occultations by (22) Kalliope and its satellite Linus were
observed in Japan at around 19:49 UT on 2006 Nov 7. As shown at URL
http://uchukan.satsumasendai.jp/data/occult/0611Kalliope-red-E.gif
positive observations of the occultation by Kalliope were reported
so far by eight observers, and those by Linus were by six, and the
observations are consistent with each other. The angular distance
between Kalliope and Linus turned out to be 0.26 arcsec at the time
of the occultation. The occultation by Linus was predicted by Dr.
Jerome Berthier of IMCCE in France (whose prediction was brought to
us by J. Lecacheux in France 19 hours before the event) and it
turned out that the prediction was accurate within about 100 km.
This is the first successful observation of an occultation by an
asteroidal satellite known previously by other means.
Sincerely yours,
Mitsuru Soma
National Astronomical Observatory of Japan Mitaka City, Tokyo, Japan
and
Tsutomu Hayamizu
Sendai Space Hall
Satsuma-sendai City, Kagoshima Pref., Japan
______________________________________________________
It was fortuitous that the path for the occultation by Linus passed
over the outer western suburbs of Tokyo where several observers were
ready to time it. At least one observer between the two shadow
paths (for Kalliope and Linus) reported no occultation.
The star that was occulted by Kalliope and Linus was 9.1-magnitude
SAO 78190 = XZ 08732 = BD +27 deg. 1049, spectral type A5.
To put this into context, for some history of occultations by
Kalliope and especially by other asteroidal satellites, and the
knowledge of existance of these objects, click here.
______________________________________________________
Date: Wed, 08 Nov 2006 12:24:26 +0100
From: jlx@meteores.net
To: Sendai-uchukan
Subject: Re: Great success (22)Kalliope
From J.Lecacheux, France.
Dear Mr. Hayamizu,
You wrote:
.......
> Unfortunately north Japan was cloudy, but I've received 14 reports till now!
> [by Main body] Video 4 ,Visual 2 / Total 6 [now 8, see above]
> [by Satellite] Video 3 ,Visual 1 / Total 4 [now 6, see above]
> [Negative] 4 .......
Sincere congratulations !
That really looks like an historic success !
Here is the provisional plot that David Dunham mailed this morning,
on which the green circle I have added is the predicted position of
Linus according to the IMCCE team of Paris and Franck Marchis of
Berkeley University. The 115 +/-20 km '(O-C)' clearly falls within
the +/-300 km uncertainty (or +/-350 km if ground projected) that I
predicted to Mr.Soma, to Mr.Setoguchi and to Sendai-Uchukan 18 hours
before the event.
Observable occultations by Kalliope are expected in s. Japan and
n.China (also Turkey, etc.) on next Jan.02 :
http://www.asteroidoccultations.com/2007_01/0102_22_8107_Map.gif
and in n.e. China on next Jan.08 :
http://www.asteroidoccultations.com/2007_01/0108_22_9735_Map.gif.
Best regards.
______________________________________
More figures, including a map showing the locations of the observations
and a more detailed view of the sky plane showing the Linus events, is
given at the URL below.
From: Mitsuru SOMA [somamt@ybb.ne.jp]
Sent: Wednesday, November 08, 2006 10:45 AM
To: Dunham, David
Subject: Setoguchi's figures for Kalliope and Linus
Although Tsutomu Hayamizu is preparing for an enlarged figure for
Linus, you can see Takashi Setoguchi's figures (map and more
detailed views) now at
http://www7.ocn.ne.jp/~set/Unlink/Kalliope.html
[Note by D. Dunham - the very elongated outline of Linus in the
figure on the above link is surely an artefact of the observations
that probably have some timing errors, and not a good distribution
across the object; it would be better to just fit a circle that
would have a radius a little less than the major axis of the
plotted ellipse since the observations aren't sufficient to
determine the true ellipticity of Linus.]
Best regards, Mitsuru Soma
_____________________________________
David Dunham, 2006 November 8
Phones home 301-474-4722; office 240-228-5609; car 301-526-5590
emails dunham@starpower.net or office david.dunham@jhuapl.edu