Central Bureau for Astronomical Telegrams
IAUC 5795: 68 Oph; 1993J
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Circular No. 5795
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
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MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
68 OPHIUCHI
A. Vidal-Madjar, R. Ferlet, A. Lecavelier des Etangs, G.
Perrin, and F. Sevre, Institut d'Astrophysique de Paris; F. Colas,
Bureau des Longitudes; F. Deladerriere, Observatoire du Pic du
Midi; and A.-M. Lagrange-Henri, Observatoire de Grenoble, communicate:
"Observations with the Bernard Lyot 2-m telescope at the Pic
du Midi Observatory on 1992 Aug. 26 revealed a disk-like structure
around the nearby main-sequence star 68 Oph (HR 6723, type A2 Vn,
distance 48 pc, mv = 4.45). The observations were done in the 695-
nm band with an 'anti-blooming' CCD camera. The disk is viewed
nearly edge-on between 1".5 and 7" from the star, the limit of our
field-of-view. It thus extends out to at least 350 AU. The disk
is inclined by 13 deg to the east of north, and its magnitude ranges
from 16 to 22 arcsecE-2. The radial luminosity of the disk is
well fit by an rE-3 power law out to 3" on both sides, and is
separated then into an rE-2 power law in the northern extension and an
rE-4 power law in the southern one. 68 Oph is known as a member of
a double system whose companion is a 6.9-magnitude star with a
separation of 0".6 in p.a. 70 deg. In addition to the strong
asymmetry observed in the disk, a slight wrapping is also detected at
more than 5" from the star -- possible signatures of the companion
interaction. Following beta Pic (Smith and Terrile 1984, Science
226, 1421), this is the second disk to be directly imaged optically,
and it is the first one related to a double system. Due to the
high S/N level (30 sigma at 3" from the star) and to the remarkable
similarity to the beta Pic disk, the detection seems to be quite
convincing, although 68 Oph does not present any infrared excess in
the IRAS Point Source Catalogue. We strongly recommend other
observations to confirm this detection."
SUPERNOVA 1993J IN NGC 3031
M. Kidger, Instituto de Astrofisica de Canarias, reports the
following infrared photometry obtained by T. Mahoney, M. Selby, and
himself using the 4.2-m William Herschel Telescope at Roque de los
Muchachos Observatory (6".7 aperture, approximately east-west 10"
chop; calibration star BS 3403, previously calibrated against Vega):
Apr. 29.818 UT, K = 10.01 +/- 0.04; May 1.837, K = 10.20 +/- 0.03;
5.840, K = 10.16 +/- 0.04, H = 10.32 +/- 0.04; 6.833, K = 10.35 +/-
0.04, H = 10.53 +/- 0.04, J = 10.87 +/- 0.04. The quoted errors
are provisional, pending reanalysis.
1993 May 18 (5795) Daniel W. E. Green
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