THE AMERICAN ASSOCIATION OF VARIABLE STAR OBSERVERS
25 Birch Street, Cambridge, MA 02138 USA
Tel. 617-354-0484 FAX 617-354-0665
AAVSO ALERT NOTICE 238 (April 8, 1997)
SUPERNOVA 1997bp IN NGC 4680
We have been informed by the Central Bureau for Astronomical Telegrams (IAU
Circular 6613) that P. Marples, Loganholme, Queensland, Australia, reports that
Robert O. Evans, Hazelbrook, New South Wales, Australia, visually discovered
a supernova in NGC 4680 on April 6.52 UT at magnitude approximately 13.8.
Visual confirmation was made by Marples on Apr 6.6 UT.
N. Grogin, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, measured
the position of SN 1997bp on CCD images he obtained Apr 7.3 UT with the Whipple
Observatory 1.2-m telescope (IAU Circular 6613), and indicates that the
supernova, magnitude V = 14.2, is located 14.6" west and 20.0" south of the
center of the galaxy, whose (2000.0) position is:
R.A. = 12h 46m 55s Dec. = -11 degrees 38.3'
Spectroscopic information showing this supernova to be a Type Ia within a week
of maximum light came from the following sources (IAU Circular 6613):
- M. Phillips, Cerro Tololo Interamerican Observatory (CTIO), Chile, who
obtained a spectrogram on Apr 7.1 UT with the CTIO 1.5-m telescope.
- D. J. Schlegel, University of Durham, England, who obtained a spectrogram
on Apr 7 with the CTIO 4-m reflector, and A. V. Filippenko and D. C. Leonard,
University of California at Berkeley, who interpreted the uncalibrated data.
- L. Wang and J. C. Wheeler, University of Texas, who interpreted a
spectrogram obtained with the McDonald Observatory 2.7-m reflector on Apr 7.2
UT. They also indicate that the spectrum is very similar to that of SN 1981B
at maximum light.
- P. Garnavich, P. Challis, and R. Kirshner, Harvard-Smithsonian Center for
Astrophysics, Cambridge, MA, who examined spectra obtained Apr 7.4 UT with the
Multiple Mirror Telescope.
Accompanying is a CCD image kindly provided by P. Garnavich which shows
NGC 4680 and SN 1997bp. Also accompanying is an AAVSO 'e' scale preliminary
chart of NGC 4680, prepared by C. Scovil and showing the location of SN 1997bp.
Please use this chart to observe the supernova, and report your observations of
1241-11 SN 4680 to AAVSO Headquarters, being certain to indicate which
comparison stars you used.
Congratulations to Bob on his latest discovery!
CHARTS AVAILABLE ON AAVSO FTP SITE
Chart links are obsolete; 11/2013 create charts using VSP at http://www.aavso.org/vsp
Electronic copies of the CCD image and AAVSO chart of SN 1997bp in NGC 4680
mentioned in this Alert Notice are available from our FTP site:
ftp.aavso.org (184.108.40.206), in /pub/alerts/alert238
The chart may also be accessed through our Web site at the following address:
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also encourage observers to send observations by fax to 617-354-0665 or by
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very much if you would report your observations in Universal Time.
Many thanks for your valuable astronomical contributions and your efforts.
Janet A. Mattei
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