Central Bureau for Astronomical Telegrams

IAUC 5654: N LMC 1992; 1992t

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                                                  Circular No. 5654
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@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)


NOVA IN THE LARGE MAGELLANIC CLOUD 1992
     H. W. Duerbeck and E. K. Grebel, European Southern Observatory,
and D. Beele, Astronomisches Institut Munster, report:  "Spectrograms
(360-1000 nm) taken Nov. 15.26 UT with the ESO/MPI 2.2-m telescope
(+ EFOSC II) at La Silla indicate that the spectral appearance
has changed dramatically in two days' time (cf. IAUC 5653).
The nova reached maximum on Nov. 13 and now shows a rich emission
line spectrum of H, N I, O I, Na I, Ca II, and Fe II (multiplets 27,
37, 38, 42, 49, 73, 74).  It also shows diffuse enhanced features:
weak absorption components of H yield expansion velocities of -1100,
-2630, and possibly -4050 km/s.  A rapid brightness decline is
indicated in Stromgren photometry obtained with the Danish 0.5-m
telescope at ESO:  Nov. 12.20, y = 10.37; 13.24, 10.20; 15.17, 11.00;
16.16, 11.60."


PERIODIC COMET SWIFT-TUTTLE (1992t)
     B. Jones and R. K. Pina, University of California at San Diego;
and E. F. Milone, Rothney Astrophysical Observatory, University of
Calgary, report that 11.7-micron images (0".83/pixel) of P/Swift-
Tuttle were obtained on Nov. 7.1 and 8.1 UT by Pina, J. R.
Sarmecanic, and Milone (field-of-view of 30" x 17") and on Nov.
12.1 and 13.1 by R. C. Puetter and J. McLaughlin (19" x 24"), using
the UCSD 10-micron array camera at the Mt. Lemmon Infrared Observatory.
The comet showed a decrease in flux of 28 percent between
the two dates, going from 37.7 to 27.3 Jy in a 5".8 beam centered
on the nucleus.
     R. D. Gehrz, G. Lawrence, and K. Flugaur, University of Minnesota;
and C. E. Woodward, University of Wyoming, report thermal infrared
measurements of P/Swift-Tuttle on Nov. 12.0 UT using a multifilter
GaGe bolometer with a 9" diaphragm on the 0.76-m telescope
of O'Brien Observatory.  The chopper throw placed the reference
beams 45" north and south of the coma center.  The infrared broadband
magnitudes are K [6.53 (3-sigma upper limit), L = 5.9 +/- 0.3,
M = 3.0 +/- 0.3, N (7-14 microns) = -0.2 +/- 0.1, Q (18-22 microns)
[-2.0 (3-sigma upper limit).  Additional photometry through the
narrow-band IRTF silicate filter set gave magnitudes of [7.8 microns]
= 0.7 +/- 0.3, [8.7 microns] = -0.3 +/- 0.1, [9.8 microns] =
-0.7 +/- 0.15, [10.3 microns] = -0.64 +/- 0.3, [11.6 microns] =
-1.4 +/- 0.3, and [12.5 microns] = -1.1 +/- 0.1.  The data are
consistent with continuum emission from a 367-K blackbody.  There is
no evidence for a strong 10-micron silicate emission feature.


1992 November 16               (5654)            Daniel W. E. Green

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