Central Bureau for Astronomical Telegrams
IAUC 5108: MWC 560; 1990g; N Sct 1989
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Circular No. 5108
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)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN or GREEN@CFA.BITNET MARSDEN or GREEN@CFAPS2.SPAN
MWC 560
A. G. Michalitsianos, R. J. Oliversen, S. P. Maran, and G.
Sonneborn, NASA/Goddard Space Flight Center, report: "Observations
with the International Ultraviolet Explorer on Sept. 26 show that
the ultraviolet spectrum of the unusual erupting star MWC 560 (cf.
IAUC 4969, 4979, 4989), sometimes classified as symbiotic, has
changed noticeably since previously observed on Apr. 29. The total
flux of MWC 560 in the range 120-320 nm dropped by roughly a factor
of 10 since Apr. 29, although the visual brightness measured by the
IUE Fine Error Sensor decreased by < 10 percent. The ultraviolet
spectrum now resembles some classical novae early in outburst,
particularly OS And on 1986 Dec. 11 and PW Vul on 1984 Sept. 1, 5 and
15 days after outburst, respectively (see Stryker et al. 1988, ESA
SP-281, 1, 149). The spectral features in the range 120-200 nm of
MWC 560 match those in OS And, but with MWC 560 being blueshifted
by 1240 km/s. This may mean that MWC 560 is a cataclysmic variable
star of a new type, which has ejected a cool, optically thick shell.
Observers should monitor MWC 560 for the possible emergence of a
nebular-phase spectrum."
COMET McNAUGHT-HUGHES (1990g)
Extended ephemeris from orbital elements on MPC 16842:
1990 ET R.A. (1950) Decl. Delta r m1
Sept.26 15 12.38 -34 46.4 3.594 3.124 16.7
Oct. 1 15 14.42 -33 47.5
6 15 16.71 -32 52.5 3.692 3.074 16.7
11 15 19.23 -32 00.9
16 15 21.93 -31 12.5 3.771 3.025 16.7
21 15 24.79 -30 26.7
26 15 27.79 -29 43.3 3.828 2.979 16.7
NOVA SCUTI 1989
Visual magnitude estimates (cf. IAUC 4996): Apr. 26.85 UT,
13.1 (A. Pearce, Scarborough, W. Australia); May 31.1, 13.4 (A.
Mizser, Budapest, Hungary); June 24.01, 13.5 (A. Pereira, Caxias,
Portugal); July 12.21, 13.9 (R. Royer, Wrightwood, CA); Aug. 19.90,
14.0 (M. Verdenet, Bourbon-Lancy, France); Sept. 18.11, 13.6 (J. E.
Bortle, Stormville, NY).
1990 October 1 (5108) Daniel W. E. Green
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