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IAUC 6082: omicron And; (243) Ida I; 1994o

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                                                  Circular No. 6082
Central Bureau for Astronomical Telegrams
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)
TWX 710-320-6842 ASTROGRAM CAM     EASYLINK 62794505

     P. Harmanec, Astronomical Institute, Ondrejov, writes:  "A
series of reticon observations (619-672 nm) of the B6 IIIe star omicron
And (the primary of a multiple system), secured at the coude focus
of the Ondrejov 2.0-m telescope on Sept. 22/23, shows a dramatic
change of the line spectrum in comparison to the previous spectrum
of omicron And obtained with the same instrumentation on Aug. 3/4.  New
spectra show a double H-alpha emission with peaks rising some 2-3
percent above the continuum level and a shell absorption with
central intensity 0.31, while the August spectrum has H-alpha in
absorption, with a shell core at central intensity 0.37.  The total
equivalent width of H-alpha has decreased from 0.628 to 0.416 nm.
Other stellar features seen in both August and September spectra
are Si II (multiplet 2) lines at 634.7 and 637.1 nm, He I at 667.8
nm, and as-yet-unidentified broad absorption at about 640.06 nm;
the Si II and He I lines are stronger in the new spectra.
Difference spectra of the present series (created by subtraction of
the first spectrum from the remaining ones) reveal the presence of
strong rapid variations in all observed stellar lines, with the
exception of the unidentified 640-nm feature.  The radial
velocities of H and He are about -19 km/s on both occasions, while
those of the Si II lines are -20 and -10 km/s from the new spectra;
all measurements refer to line wings."

1993 (243) 1 = (243) IDA I (DACTYL)
     At the recent meetings of the IAU, the presumed satellite of
(243) Ida mentioned on IAUC 5948 was given the permanent
designation (243) Ida I and the name Dactyl.

     Several observers have reported that the primary component (A)
of this comet has become diffuse and much fainter in the past week,
while component D has brightened and become much more condensed.
Total visual magnitude estimates of component A (cf. IAUC 6075):
Sept. 17.13 UT, 7.6 (A. Diepvens, Balen, Belgium, 0.15-m refractor);
24.50, 9.0 (C. S. Morris, Pine Mountain Club, CA, 0.26-m reflector);
25.49, 9.0 (Morris; 4'.4 coma); 25.83, 9.4 (J. Kobayashi, Kumamoto,
Japan, 0.41-m reflector).  Total visual magnitude estimates of
component D (cf. IAUC 6081):  Sept. 16.09 UT, 9.7 (L. Szentasko,
Veresegyhaz, Hungary, 0.33-m reflector); 24.50, 8.8 (Morris);
25.50, 8.6 (Morris; 2'.9 coma); 25.83, 9.0 (Kobayashi).

1994 September 26              (6082)            Daniel W. E. Green

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