Central Bureau for Astronomical Telegrams
IAUC 4740: 1989A
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Circular No. 4740
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
SUPERNOVAE 1989A IN NGC 3687 AND 1989B IN NGC 3627
M. Kidger, Instituto de Astrofisica de Canarias, communicates:
"Infrared monitoring by J. Casares, P. Garcia-Lario, A. Mampaso, M.
Manteiga, and myself was done with the 1.5-m Carlos Sanchez
Telescope in El Observatorio del Teide, Tenerife, during Jan. 24-
Feb. 5. JHK monitoring of SN 1989A was performed on nine nights
from Jan. 24 to Feb. 5; maximum (J = 13.8 +/- 0.15, J-H > +0.3, J-K
> 0.0) occurred on Jan. 30, while maximum in K (13.6 +/- 0.3)
preceeded the J maximum by about 4 days. SN 1989B was monitored
on four nights from Feb. 1 to 5; maximum in J (11.28 +/- 0.03, J-H =
+0.07, H-K = +0.17) was observed on Feb. 3, while maximum in H and K
preceded this by at least two days. The color indices are constant
within the errors, although there is a slight tendency for the H-K
index to decrease, in line with previous type-I supernovae, as the
rate of decline in K (0.058 mag/day) is significantly faster than
in H (0.045 mag/day). Infrared monitoring of SN 1989B will be resumed
in early March. We encourage other groups to monitor this bright
supernova in the infrared during and after this hiatus. CCD
photometry of SN 1989A by D. Jones, El Observatorio del Roque de los
Muchachos, La Palma, with a coated GEC chip on the 1-m Jacobus Kapteyn
Telescope on Jan. 24 and 25 gave identical magnitudes (V = 14.11, R =
14.16, I = 14.38) on both nights. A spectrum of SN 1989B taken by
R. Ellis and J. Allington-Smith, University of Durham, at the 4.2-m
William Herschel Telescope on Feb. 1 (communicated by P. Charles,
and interpreted by P. Ruiz-Lapuente, R. Lopez and R. Canal, University
of Barcelona) confirms that this supernova was near maximum on Feb. 1.
The characteristic lines of a type-Ia SN at this phase are present:
the Si II (635.5 nm) line at 613 nm, the S II (546.8, 565.4 nm) doublet
at 527.5 and 545.0 nm, the O I (777.3 nm) line at 748.0 nm, and the
Ca II (857.9 nm) infrared line at 824.5 nm. The velocities inferred
from absorption minima corrected for the redshift of the host galaxy
indicate the presence of Si II and S II expanding at 11 000 km/s,
whereas O I and Ca II are expanding at the larger velocity of 12 000 km/s."
J. C. Wheeler, University of Texas at Austin, reports: "SN 1989B
in NGC 3627 was observed on Jan. 31 and Feb. 1 UT by K. Thompson and
R. Goodrich at McDonald Observatory with the near-infrared spectrometer.
The low-resolution spectra, covering 2.03 to 2.33 microns at 0.0107-micron
dispersions, show no features above the noise. Signal-to-noise ratios
were estimated at 23 and 19, respectively."
1989 February 16 (4740) Daniel W. E. Green
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