Electronic Telegram No. 4390
Central Bureau for Astronomical Telegrams
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PSN J20344424+6011359 = SUPERNOVA 2017eaw IN NGC 6946
     P. Wiggins, Tooele, UT, USA, reports his discovery of a possible
supernova (mag about 12.8) on an unfiltered CCD frame taken on May 14.238 UT
using a 0.35-m f/5.5 reflector near Erda, Utah.  The new object is located at
R.A. = 20h34m44s.24, Decl. = +60d11'35".9 (equinox 2000.0), which is about
153" northwest of the center of NGC 6946.  The discovery image was posted
at website URL http://users.wirelessbeehive.com/~paw/ngc6946-1.jpg.  Wiggins
notes that nothing was visible at this position on an image taken on May 12.
The variable was designated PSN J20344424+6011359 when it was posted at the
Central Bureau's TOCP webpage; it has also received the designation SN
2017aew via the new IAU designation website (http://wis-tns.weizmann.ac.il/)
for supernovae.
     E. O. Waagen, American Association of Variable Star Observers, reports
the following visual magnitude estimates for PSN J20344424+6011359 = SN
2017eaw:  May 15.224 UT, 13.0 (C. Maloney, Helena, AR, USA); 15.371, 12.9
(L. Shotter, Uniontown, PA, USA); 15.896, 12.8 (A. Morozov, Novozybkov,
Russian Federation); 16.031, 12.9 (K. Wenzel, Grossostheim, Germany);
16.178, 12.8 (Shotter); 16.382, 12.7 (C. Chiselbrook, Canton, GA, USA).
Selected CCD magnitudes reported to the AAVSO:  May 14.503, B = 13.45 (J.
Foster, Los Angeles, CA, USA); 14.506, V = 13.10 (Foster); 14.508, I = 12.68
(Foster); 14.883, B = 13.19 (D. Blane, Henley-on-Klip, S. Africa); 14.908, R
= 12.87 (R. Nogues Naves, Cabrils, Spain); 14.910, V = 13.11 (Blane);
14.912, V = 13.09 (A. Mantero, Bernezza, Italy); 15.083, V = 13.12 (I.
Cervini, Leontica, Switzerland); 15.348, V = 13.03 (B. Harris, New Smyrna
Beach, FL, USA); 15.350, R = 12.79 (Harris); 15.965, R = 12.71 (Nogues
Naves); 15.971, V = 12.95 (Nogues Naves); 16.079, V = 13.00 (Cervini);
16.171, V = 12.89 (T. Arranz, Navas De Oro, Spain).
     D.-f. Xiang, L.-m. Rui, and X.-f. Wang, Tsinghua Univeristy; Jianning Fu
and Y.-p. Zhang (Beijing Normal University), F. Xiao, and Tianmeng Zhang,
National Astronomical Observatories of China (NAOC); and Jujia Zhang, Yunnan
Astronomical Observatories, report on an optical spectrogram of PSN
J20344424+6011359 = SN 2017eaw that was obtained on May 14.79 UT with the
2.16-m telescope (+ BFOSC) at the Xinglong Station of the NAOC.  The spectrum
is consistent with that of a young type-IIP supernova at one week before
maximum light.  Cross-correlation with a library of supernova spectra using
the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J.,
666, 1024) shows that 2017eaw matches with SN 1999gi at about 7 days before
peak brightness.  After correcting for a redshift of 0.000133 for its host
galaxy, NGC 6946, an expansion velocity of about 10600 km/s can be derived
from the absorption minimum of the H-alpha line.  This is the tenth
supernova recorded in this nearby spiral galaxy over the past century.


NOTE: These 'Central Bureau Electronic Telegrams' are sometimes
      superseded by text appearing later in the printed IAU Circulars.

                         (C) Copyright 2017 CBAT
2017 May 16                      (CBET 4390)              Daniel W. E. Green