[IAUC] IAUC 9184: Occn BY (136199); C/2010 V1 [25139-2011/04-R1]

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                                                  Circular No. 9184
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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 20 Oxford St.; Cambridge, MA  02138; U.S.A.
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OCCULTATION BY (136199) ERIS
     Jose L. Ortiz, N. Morales, R. Duffard, A. Thirouin, P. Santos-
Sanz, and I. de la Cueva, Instituto de Astrofisica de Andalucia,
CSIC, Granada, Spain, report that the occultation of a star of
magnitude V about 17 by the dwarf planet (136199) Eris has been
successfully recorded from their remotely-operated 0.4-m ASH2
telescope at S. Pedro de Atacama Celestial Explorations Observatory
in Chile, with the event starting on Nov. 6d02h18m39s +/- 7 seconds
and lasting for 67 +/- 15 seconds.  These observations confirm that
the shadow path of the event drifted southward of most of the
latest predictions, which were compiled by B. Sicardy at website
URL http://tinyurl.com/2fsotul, and also by S. Preston at website
URL http://tinyurl.com/2dqqol5.

     E. Jehin, J. Manfroid, M. Gillon, D. Hutsemekers, and P.
Magain report that they observed an occultation of a star of
magnitude I about 15.2 by the dwarf planet Eris (then at V about
18.7) on Nov. 6 using the new telescope TRAPPIST at the European
Southern Observatory (La Silla).  A series of 3-s exposures of a
field of size 3' x 3' (1".3/pixel) were secured in fast-readout
mode (with a deadtime of 1.5 s), starting at 01h50m UT for one hour.
Seven frames centered at 02h19m34s UT allowed them to derive the
start of the occultation as 02h19m16s.75 +/- 0s.75 and the end as
02h19m47s.6 +/- 0s.2, for a total occultation time of 30.4 +/- 1.0
seconds.  The predictions (see above) made by the Rio de Janeiro
group (Assafin et al., Nov. 5) and by J. L. Ortiz estimated the
time of the occultation around 02h18m UT for Chile, in good
agreement with the observations.  During the occultation, a point
source is detected with a magnitude corresponding to that of Eris.
A small flux increase was also seen at the middle of the
occultation, which might result from refraction in Eris' atmosphere
(Elliot and Olkin 1996, Ann. Rev. Earth Planet. Sci. 24, 89).  Eris
is by far the most-remote solar-system object observed to date via
stellar occultation, with a geocentric distance of about 96 AU.
TRAPPIST is a project driven by the University of Liege, in close
collaboration with the Observatory of Geneva, supported by the
Belgian Fund for Scientific Research and the Swiss National Science
Foundation.


COMET C/2010 V1 (IKEYA-MURAKAMI)
     Additional visual total-magnitude estimates (cf. IAUC 9176):
Nov. 5.82 UT, 8.5 (S. Yoshida, Gunma, Japan, 0.40-m reflector);
7.31, 8.5 (J. G. de S. Aguiar, Campinas, Brazil, 25x100 binoculars).

                      (C) Copyright 2010 CBAT
2010 November 8                (9184)            Daniel W. E. Green