Central Bureau for Astronomical Telegrams
IAUC 4288: SNe
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 4289
Circular No. 4288
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 617-495-7244/7440/7444
SUPERNOVAE
A. V. Filippenko and J. C. Shields, University of California
at Berkeley, report that mediocre spectra (range 450-960 nm,
resolution 0.8-1.6 nm) obtained on Dec. 25 and 26 with a CCD
spectrograph on the Shane 3-m reflector at Lick Observatory reveal that
SN 1986M in NGC 7499 (IAUC 4282, 4284) is indeed a supernova. The
spectra exhibit broad undulations, and hydrogen is absent, as in
type I objects, but the relative positions and profiles of the main
features appear unusual. In particular, the 615-nm absorption
trough normally seen in type Ia supernovae is absent, and there
are broad peaks at rest wavelengths of approximately 459, 491, 556,
and 648 nm. The spectra most closely resemble those of the carbon/
oxygen-rich type Ib supernovae 1983I and 1983V roughly 20 days past
maximum, obtained by J. C. Wheeler, R. P. Harkness and colleagues
(preprint). The visual magnitude is consistent with the conclusion
that it is a type Ib supernova within a month past maximum brightness,
since the redshift of NGC 7499 is 12 000 km/s. Additional
spectra, however, are necessary to verify this classification.
Spectra of the type II supernovae 1986E and 1986I roughly 9
and 7.3 months past maximum (respectively), obtained at Lick on
Dec. 27 exhibit very strong H-alpha emission superposed on a weak
continuum. Strong [O I] 630.0, 636.4 and [Ca II] 729.2, 732.4 are
also present, as are many weaker emission lines. H-beta is very faint
and may be entirely absent in SN 1986E. The FWHM of H-alpha is about 2500
km/s, and the other features have comparable widths.
Filippenko and Shields also report that high-quality spectra
(range 310-960 nm) obtained with the same telescope on Dec. 26
show SN 1986N (IAUC 4287) to be a type Ia object, 20 +/- 5 days past
maximum brightness. The absorption trough at 615 nm is prominent,
as are the broad maxima at 465 and 540 nm. The Ca II triplet (850
nm) has a P-Cygni profile.
R. H. McNaught, Siding Spring Observatory, reports the following
precise position of SN 1986N from a IIIa-F exposure taken on
Dec. 27.65 UT with the Uppsala Southern Schmidt telescope: R.A. =
4h46m09s.58, Decl. = -6 24'33".8 (equinox 1950.0). The supernova is
located 12" west and 9" south of the ill-defined nucleus of the
parent galaxy NGC 1667.
1986 December 30 (4288) Brian G. Marsden
Read IAUC 4289
Our Web policy. Index to the CBAT/MPC/ICQ pages.
