Central Bureau for Astronomical Telegrams
IAUC 3476: 4U 1145-61; SATURN'S F RING; NOTICE RE Tlgms
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Read IAUC 3477
Circular No. 3476
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
4U 1145-61
M. Pakull, C Motch and J. Lub, European Southern Observatory;
and B. Reipurth, Copenhagen Observatory, telex: "The Be-star Henize
715 (= 4U 1145-61) has recently undergone substantial changes in
its colors and luminosity. From 1976 Apr. to 1979 June it was
relatively stable at V = 8.94, B-V = +0.20, U-B = -0.82, with small
but significant fluctuations of ~ 0.06 mag. On 1979 Dec. 30 it was
0.15 mag fainter, and during 1980 Feb. it declined further. Recent
photometry during the second half of Apr. yields V = 9.20, B-V =
+0.11, U-B = -0.86, with a slight tendency to rise again. Infrared
colors compared with earlier measurements (Glass 1979, M.N. 187,
807), and the B-V color index, show that the red and infrared excess
of Henize 715 has almost disappeared. This would indicate
that it has lost its circumstellar envelope. We urge spectroscopic
and particularly x-ray observers to follow the object during the
forthcoming months, as this might provide the key for understanding
the Be/x-ray phenomenon."
SATURN'S F RING
The Space Telescope Wide-Field Camera Instrument Definition
Team reports: "The F ring of Saturn appears as a strong feature in
a number of images recorded at the U.S. Naval Observatory in
Flagstaff in March, when the earth was in the vicinity of the Saturn
ring plane. The Saturn disk, the A and B rings and five individual
bright satellites were all occulted at the telescope focal plane,
and the remainder of the image was relayed to the detector with a
lens containing a coronagraphic mask to remove light diffracted by
the telescope. The detector was a 500 x 500-pixel CCD system
developed by the ST-WFC Team for ground-based use. The F ring is
easily seen out to more than eight Saturn radii. It tapers off in
brightness outward but appears somewhat lumpy. It probably commences
not far outside the A ring, but edge-on data cannot define
the inner limit."
NOTICE CONCERNING TELEGRAMS
It is once again an 'open season' for making changes in the
lists of subscribers to the Central Bureau's telegram service.
Subscribers who wish to make address changes, category changes, etc.,
are requested to inform us of said changes by June 30.
1980 May 12 (3476) Brian G. Marsden
Read IAUC 3477
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