Central Bureau for Astronomical Telegrams
IAUC 5299: N LMC 1991; 1991aa; 1989t
The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).
Read IAUC 5300
Circular No. 5299
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
NOVA IN THE LARGE MAGELLANIC CLOUD 1991
G. Sonneborn, Goddard Space Flight Center, NASA; S. N. Shore,
Goddard High Resolution Spectrometer, Computer Sciences Corporation;
R. Gonzalez-Riestra, A. Cassatella, and D. de Martino, IUE Observatory,
European Space Agency, Madrid; and S. G. Starrfield, Arizona
State University, report: "Observations with the International
Ultraviolet Explorer (IUE) satellite show that the ultraviolet spectrum
of Nova LMC 1991 changed from a cool, opaque shell to that of a
high-temperature plasma between May 2 and 22 (cf. IAUC 5253, 5257).
Recent spectra (June 22) show N V 120-nm, Si IV + O IV 140-nm, N IV]
149-nm, C IV 155-nm, He II 164-nm, O III] 167-nm, N III] 175-nm, C
III] 191-nm, C II] 232-nm, Al II 264-nm, Mg II 280-nm, and O III]
313-nm, all with FWHM = 3300 km/s. The ionization level rose between
May 22 and June 22: N V, N IV], and C IV fluxes increased 20-
40 percent; C III], N III], O III], and He II fluxes decreased 15-30
percent. On June 22 the hot continuum had faded to 20 percent of
its flux level on May 22, close to the IUE detection threshold.
Upper limits on continuum fluxes (in units of 10E-15 erg cmE-2 sE-1
AE-1) are: 145 nm, </= 2.1; 180 nm, </= 1.8. Integrated ultraviolet
fluxes (122-200 nm; in units of 10E-11 erg cmE-2 sE-1) are: May
2.71, 9.05; 22.02, 2.00; June 22.47, 1.01. The outburst lightcurve
shows that ultraviolet maximum was on Apr. 30. The nova will be
observed by IUE between July 21 and 25. Observations at other
wavelengths are needed during this period."
SUPERNOVA 1991aa IN ANONYMOUS GALAXY
R. H. McNaught, Anglo-Australian Observatory, reports that red
exposures with the Uppsala Southern Schmidt on May 15, 16, 18, and
June 1 confirm that this supernova was brightening at discovery (cf.
IAUC 5267). The brightening was gradual, reaching about 1.5 mag
brighter than discovery by June 1.
PERIODIC COMET WILD 2 (1989t)
Total visual magnitude estimates: Apr. 11.48 UT, 12.8 (A. Hale,
Las Cruces, NM, 0.41-m reflector); 17.85, 13.0 (A. Pearce, Dowerin,
W. Australia, 0.41-m reflector); May 12.83, 13.5 (Pearce, Scarborough,
W.A.); 19.45, 12.9 (Hale); June 8.33, 13.0 (C. S. Morris,
Lockwood Valley, CA, 0.51-m reflector); 15.29, 13.2 (Hale).
1991 July 5 (5299) Daniel W. E. Green
Read IAUC 5300
Our Web policy. Index to the CBAT/MPC/ICQ pages.
